Human Movement Potential: Its Ideokinetic Facilitation 0396069037, 9780396069034

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Human Movement Potential Its

Ideokinetic Facilitation

HUMAN MOVEMENT Its

POTENTIAL

Ideokinetic Facilitation

HUMAN MOVEMENT Its

Ideokinetic Facilitation

Sweigard, Ph. D.

Lulu

E.

Harper

& Row,

New

POTENTIAL

Publishers York Hagerstown San Francisco London

HUMAN MOVEMENT POTENTIAL: Copyright

Its

Ideokinetic Facilitation

© 1974 by Harper & Row, Publishers, Inc.

No part of this book may any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles and reviews. For information address Harper & Row, Publishers, Inc., 10 East 53rd Street, New York, N.Y. 10022.

All rights reserved. Printed in the United States of America.

be used or reproduced

in

Library of Congress Catalog Card Number: 73-15390

Standard Book Number: 06-046521-2 Designed by Jeffrey M. Barrie

Preface

How

does movement proceed, and

how can it be performed with greater answer these questions, this book focuses on the interdependence of postural aHgnment and the performance of movement. It provides an educational method which stresses the inherent capacity of the nervous system to determine the most efficient neuromuscular coordination for each movement. Through this book, I hope to offer my method of teaching body balance and efficient movement which has been developed during many years of research and teaching to a wider audience than has been possible within the efficiency? In striving to

—

—

confines of the classroom or the private studio.

Movement

is,

of course, a neuro-musculo-skeletal

method presented here emphasizes for securing

neural aspects; these hold the secret

and maintaining neuromuscular

benefits. In this respect, the

generally

its

method

efficiency, with all

differs significantly

employed in teaching posture,

phenomenon. The

fitness,

its

salutary

from the procedures

and therapeutic exercises. In

—

from the general procedure for teaching skills be they in an occupation, a sport, or one of the performing arts. Although the standard methods often produce the outward effects desired, they frequently build strain which can, in turn, lead to premature debilitation and actual loss of

fact, it differs

efficiency in

Many

movement.

outside influences have contributed greatly, both directly and

indirectly, to the evolution of

Mabel Elsworth Todd,

my

basic philosophy in teaching

movement.

Columbia University, provided the initial impetus to pursue a new approach to movement education. Her approach differed markedly from the methods then in vogue in that it used various forms of imagery as a means of achieving better postural alignment. It was the influence of her teaching which ultimately led to my research on skeletal alignment. This research confirmed the validity of her method and provided

me

at Teacher's College,

with the basic information for

my own

approach

to

movement

education.

Strong support for and endorsement of these research studies came from Dr. Jay B. Nash at New York University. In his department I did the research on skeletal deviations as well as much of my early teaching.

Later Martha Hill, head of the Dance Division at the Juilliard School, lent her support to my ideas. Through her insistence, this teaching method was

PREFACE

vi

introduced into

Juilliard's

curriculum.

freedom of teaching, so necessary

And

it

was her granting me complete which permitted the refine-

in education,

ment of my method to its present level. By observing the students of Antony Tudor and Jose Limon in

actual class

work, I learned to appreciate the particular needs of the dancer. The many years of close association with Betty Jones during my tenure at the JuiUiard School also helped me immeasurably in evolving and applying my technique

needs of the dancer. however, to organize and select the material to be incorporated in this book, I soon became inundated with the broad spectrum of scientific information pertinent to the subject. What material could be to the

When the time arrived,

my

had come to realize that teachers and students often lacked an adequate academic or functional knowledge of the human body. For this reason, the book includes information from the various sciences ranging from the simple to the complex, but all basic to the education needed for the understanding of movement. I particularly have emphasized factual anatomical knowledge and the functional integration of this knowledge with the method of movement education. In preparing the text I received the capable and continuous support of many friends, both in the form of professional help and simply in making easier the stresses and strains of the chores of everyday life, especially during a long period of illness. The primary impetus and encouragement for the book came fi-om my students, and through their persistent questioning many a thought was refined and crystalized. There were, however, two people whose help went far beyond that normally received. Without their assistance, I would have found the book included? Through

difiicult, if

years of teaching,

I

not impossible, to complete.

The most valuable

criticisms

and suggestions emerged from a long-term J. Huelster, Professor Emerita of Physical

exchange of ideas with Dr. Laura Education, University of Illinois. critical

Her high standard of professionalism

evaluation of the manuscript as

it

progressed from the

first

in the

concept to

completion reflected a degree of integrity and honest friendship that one seeks but rarely finds. Equally as much help was given by Fritz E. Popken, my husband. As a research biologist whose activities had taken him into a variety of fields, he was able to give invaluable aid in evaluating much of the more recent informa-

on muscle contraction and the functioning of the nervous system. He unstintingly gave of his talents toward the writing of the text and was a tion

continuous source of inspiration and encouragement. I also wish to thank Read Arnaud Arnow for his patience and skill in preparing the drawings, and Jean Fahrenbach for her professional help with the references and index.

Lulu

E.

Sweigard

Contents

Preface

^

Fart One: The Mechanical

and Anatomical Components of

Human Movement 1.

Basic Concepts

2.

Structural

3.

Laws and Principles of Mechanics The Lever as the Machine for Movement The Pelvis The Spinal Column The Femur and Femoral Joint The Knee and Leg The Ankle Joint and Foot The Upper Extremity The Rib-Case and Diaphragm

3

Components of Body Alignment and

Movement 4. 5. 6. 7. 8.

9.

10. 11.

8

Physical

Fart Two: The Neuromuscular Production of 12.

The Muscle Engine

13.

Muscles

14.

Principles of Muscle Function

15.

The Role of the Nervous System

at

16

22 31

42 58 72

84 96 110

Movement 121

Work

129 144 in

Movement

153

Fart Three: Patterns of Skeletal Alignment 16.

Posture: Skeletal Alignment in the Standing Position

173

17.

Skeletal Deviations Identified in Postural

Alignment

187

Part Four: Facilitators for the Improvement of Posture

and Movement 18.

The Posture Laboratory

19.

Constructive Rest

20.

Imagined Movement: An Ideokinetic Lines-of-Movement and Imagery

21.

Facilitator

205 215 222 232

viii

CONTENTS

Part Five: Techniques to Reduce Strain and Improve

Neuromuscular Coordination 22. 23.

Good Mechanics In Everyday Movement Movement

261 274

Voluntary

Principles to

Guide the Use of Voluntary Movement

Techniques Voluntary

Movement with Imagery

Respiration

Hissing

Centered Breathing Head Flexion on the Spine Shoulder Tips Moving Forward or Upward Toward the Eyes Realignment of the Forward Head Thigh Flexion Movement of the Feet and Ankles Flexion (Dorsi-flexion) of the Foot Flexion of the Little Toes Rotation of the Foot Lateral Weight Transfer Leg and Arm Movement Forceful Stretching of Muscles Tests of Skeletal Alignment and Joint Flexibility The Fold-Up Position Sitting with the Legs to One Side ,

275 276 277 278 280 281 283 287 289 295 296 298 298 299 299 302 304 304 305

HUMAN MOVEMENT Its

POTENTIAL

Ideokinetic Facilitation

Part

ONE

The Mechanical and Anatomical Components of

Human Movement

*^^^^^^^^^^>^^^^^^^^^^^^^^^^

Basic Concepts

Movement is a neuro-musculo-skeletal event. The nervous system initiates movement and controls its patterning. It stimulates the muscle, the work horse, into action to move the skeleton, the machine for movement. There can be no efficiency in movement, nor can there be realization of the potential for

movement

unless

all

three

full

components— nerves, muscles,

bones — perform with optimal facility. Man's potential for movement is defined as that optimal degree of movement inherently possible by and within the human structure, performed both effectively and efficiently, that is, with minimal expenditure of energy to achieve the desired goal.

Our

potential for

movement

is

rarely developed

except possibly by a few extraordinary persons. In general, primitive

man

moved as well as his civihzed counterpart does. The educational procedure presented in this text supplies a method of teaching and learning by which human movement can be more fully develit not only is effective but also can be maintained through most of life without incurring the debilitating effects of premature wear and tear. This procedure draws heavily on the various sciences that contribute to the understanding of the complex phenomenon of movement. It fully recognizes and stresses the importance of the design of the human structure in the mechanics of movement, the mechanical laws governing all forms of motion, the role of muscle work, and— in particular— the various aspects of the function of the nervous system in human movement. The role of the nervous system throughout all our activities is so pervasive that it is indeed difficult to delimit its sphere of influence. The nervous system gives us the ability to acquire and retain knowledge, to disseminate and transmit knowledge from a blend of past and new experiences, and to develop the wisdom to accept only that which best serves our purpose. Fortunately, there resides within the nervous system a good deal of innate wisdom which automatically chooses, if given the chance, the neuromuscular pathways best suited to reach a given goal in movement. It is particularly important that this wisdom be trusted and affirmed in the teaching of movement.

oped, so that

COMPONENTS OF HUMAN MOVEMENT

4

The

capacity of the skeleton for the internal mechanics of

resides in

ment

is

its

structure

and alignment.

good, the f^hance for

If

movement

the mechanical balance of

eff iciency — good

its

align-

movement with minimal

muscle work — is increased. The amount of work a muscle can do is a function of the quality of its contractile mechanism. This mechanism must be if it is not, it may actually inhibit movement. To and responsiveness, muscles must work; an idle mus-

responsive and elastic; retain their elasticity

soon deteriorates.

cle

The nervous system coordinates all movement. Some of the influences activity for movement are under our voluntary control while others are left to the automatic wisdom built into the system. Our voluntary influence on movement is limited to controlling starting, stopping, direction, range, speed, and force. We can and do set the goal for movement, but this is where voluntary control ends. The choice of muscles whose coordinated work will achieve the goal and the selection of the nerve pathways over on

its

which the messages

We if

travel to these muscles reside in the nervous system.

can voluntarily interfere with

the goal

is

this process

not being achieved, but

we

and redirect our movement

cannot voluntarily impose con-

on muscle coordination and hope to attain efficiency. Out capacity to learn movements functions at birth; the ability to move increases gradually from simple kicking to sitting, crawling, standing, walking, running, jumping, and all the diverse movements associated with everyday activities. Learning proceeds by an inherent desire to move, by trial and error, by imitation, and by indoctrination. Once a movement has been learned, its performance becomes automatic; it is a part of the person's habit patterns of movement, which may or may not be efficient. Obviously, learning a new movement does not guarantee that this movement will be performed with utmost efficiency or that it will reach the potential inherent trols

in the structure.

When we speak of the

learning process we frequently seek our explanafrom animal studies. In so doing, we often fail to consider that the experimental animal is "kicked out of school" after it has learned one procedure. This is not because the animal is no longer able to learn, but because it is no longer naive and is, therefore, capable of self-instruction (36). This phenomenon of self-instruction is one of the greatest handicaps to movement education, because self-instruction uses established neuromuscular coordination, which is not necessarily the most efficient. For this reason there are a number of points that any teacher of movement should always remember: (1) the student is a unique personality with formed habits and behefs; (2) learning implies change, but not necessarily

tions

for the better; (3) our ability to build

greatest assets, but

experience

is

it

poor; (4)

on past experiences is one of our prove to be the greatest handicap if past the subtle effects of the mind on movement can be a

may

also

BASIC CONCEPTS

5

source of either serious error or great value; and (5) traditional concepts and loyalties die hard. Historically,

much

of our concern with the teaching of

dealt with conformity rather than with efficiency of

movement has

movement. The worst

offender has been the military, whose training programs date back farther than any other form of physical training. The national systems of gymnas-

tics—German, Swedish, Danish — are Hkewdse rigid exercises. But the emphasis on conformity and precision demanded in supposedly "good" and "beneficial" movement does not end here. It permeates modem competitive gymnastics with its "free exercise," warm-up exercises, and dance-technique exercises. Even some of the "fitness"

By pushing, a certain norm in

tests are suspect.

and stretching the body and its parts, and movements is finally reached. It is reached, however, after an unnecessary expenditure of energy. Although such waste of energy can be tolerated in youth, the price paid for these excesses and the inefficient neuromuscular habits they build in the body will be exacted later in Hfe, possibly in the form of recurrent backaches, an early onset of osteoarthritis in the most stressed joints, or inefficiency and stiffness of movement. What happens in these programs is that the skeleton (the structure that is stabilized and moved) is arbitrarily forced into positions and movements by means of an excess of muscle work. The structure may look well-balanced, pulling, holding,

positions

but how long it will move with the inefficiency established in the neuromuscular patterns remains unanswered. Many an athlete remains in his prime for a woefully short time, and many a dancer's career is forcefully terminated long before it reaches its peak. Movement education, then, must deal not only with effectiveness but

movement if it is to be permanently beneficial. Inmovement means that an unnecessary amount of energy is continually being used to hold and move the structure — the skeleton. No machine, animate or inanimate, works efficiently when not in balance, also with efficiency of

efficiency of

because energy must be spent to overcome the effects of imbalance. Deviations from mechanical balance in the skeleton are common. With them, muscles need to contract to a greater extent to maintain the poorly aligned balance of skeletal parts.

Some

of these deviations are the product of

ill-

most of them, however, result from improper habits of movement maintained since early childhood. Skeletal alignment and movement performance are completely interdependent. Improvement in the mechanical efficiency of either one automatically leads to improvement in the other. Since these deviations from mechanically efficient skeletal alignment prevent attainment of the optimal range of movement inherent in the structure, it becomes imperative that movement education concern itself, insofar as possible, with eliminating them. One way to do so is to improve poor

ness, injury, malnutrition, or genetic defects;

6

COMPONENTS OF HUMAN MOVEMENT

movement

habits. Established habits,

however, be they poor or good, are

difficult to change, especially v^hen strenuous activity is dominant in one's life. Change is possible only through the enormous task of recoordinating

the neuromuscular pathways responsible for the habitual balance and patterns. It can be accomplished only if the method of teaching

movement

informs, stimulates, and challenges the student.

which accomplishes these aims is based on the rationale that all voluntary contribution to a movement must be reduced to a minimum to lessen interference by established neuromuscular habits. The all-important voluntary contribution from the central nervous system is the idea of the movement. Concentration on the image of the movement will let the central nervous system choose the most efficient neuromuscular coordination for its performance, namely, the innate reflexes and feedback

The method

of teaching

mechanisms. The idea of the movement alone suffices to start all movement along its most suitable path. This concept as a method of teaching was first proposed by Todd (84, 85). Her basic premise was that "concentration upon a picture involving movement results in responses in the neuromusculature as necessary to carry out specific movements with the least effort" (84, p. 49). She derived this theory empirically, through extensive experimentation. As she said, "It may sound silly, but it works" (85, p. 216). She considered three factors as being essential for eliciting the proper response from an image to create the conditions for appropriate

movement

response: exact location of the

movement, the direction of the movement, and the desire to move (85). She identified the process operant in her teaching as psychophysical or psychophysiological.

Todd's method of teaching led this author to study direction of

(1) the location and framework in response to the use of the alignment of the skeletal framework in relation to the

movement

imagery, and

(2)

in the skeletal

(Chapter 17). The results of these experiments led the author not only to agree with Todd's hypothesis but also to adopt it for teaching both physical education and the performing arts — specifically, the dance.

line of gravity in the upright position

The author's teaching method uses imagined movement, the idea of movement occurring within one's body in a specific place and direction, but not being voluntarily performed. A similar philosophy of teaching has evolved in the performing arts, notably in playing the piano (8) and the violin (35). It is not too surprising that such methods have been apphed,

because movement techniques of the arts mastered and performed with minimal physical effort before full attention can be given to the artistic rendition. Indeed, mental practice without the simultaneous physical performance of a movement can have a albeit spottily, in these fields,

must be

fully

salutary effect on the learning process of

new motor

skills (69).

BASIC CONCEPTS

Among the

identifying labels used in this

method

7

have been psychophysical and psychophysiological, introduced by Todd, and psychomotor (82) and ideomotor. After reviewing past terminology, the author has accepted the term ideokinesis as most precisely describing the basic philosophy of this teaching procedure. This term

is

of teaching

also

used by Bonpen-

siere (8).

Kinesis

is

tional

movement induced by stimuand characterized by qualitative and quantitative posi-

motion, here defined as physical

lation of muscles

changes of the skeletal parts. Ideo, the idea, the sole stimulator in the is defined as a concept developed through empirical mental pro-

process,

The idea, the concept of movement, is the voluntary act and the sole voluntary component of all movement. Any further voluntary control only interferes with the process of movement and inhibits rather than promotes efficient performance. Imagined movement is best defined as an ideokinetic cesses.

facilitator.

The

utility of

culo-skeletal

ideokinesis as a teaching philosophy for the neuro-mus-

phenomenon

of

movement depends upon

a thorough

know-

ledge of the universal laws of mechanics, the skeletal structure, and the principles of muscular

and neurological function. Without

this

knowledge,

the rationale for ideokinesis as a teaching concept as presented in this text

could not have been developed, and

its

fruitful application to

teaching

becomes impossible. Therefore, all facets of movement and all basic ingredients which make up and influence movement must be thoroughly explored and examined before ideokinesis can be applied. Ideokinesis promotes a better balanced structure and, most important, greater efficiency in movement. Ultimately, ideokinesis facilitates our optimal potential for movement and helps us to preserve that movement for the greatest

number

of years of activity.

Structural

Components

of

Body Alignment and Movement

any subject, the student must first learn the language used Here the student must become familiar with the names of various parts of the body, the skeletal structure in particular, and must be able to describe and locate these parts. He must know the kinds of movement that occur in the joints of the skeleton and the names applied to these different movements. Terms such as hips, hip joints, backbone, and stomach muscles usually are avoided in this text because they often promote inaccurate concepts or vagueness concerning their location in the body. For example, stomach muscles have nothing whatever to do with voluntary movement; the stomach is an internal organ. Hip and hip joint are anatomical terms, but most people, even some who have studied anatomy, cannot In studying

in the field.

them accurately. Movement in the human body

locate

from a rather complex interaction and cartilaginous structures, activated by the work of muscles directed by messages from the central nervous system. The facts presented here are basic to an understanding of movement. A successful teaching process must use them to stimulate the ideation which can facilitate efficiency in movement. For the identification of location and direction of movement we use of bones, joints,

simple terms

and

results

their ligamentous

like:

front, anterior, ventral

v.

back, posterior, dorsal

up, superior, cephalic

v.

down,

side, sideways, lateral

v.

center, median, mesial

proximal (closer to center)

v.

distal (farther

inferior,

caudal

from center)

The Planes of the Body Often

it

helps to locate

in the body,

known

movement

in relation to three

imaginary planes

as the cardinal or orientation planes (33. p. 2),

The

Figure

1.

The planes

of the

body

in

median

position.

COMPONENTS OF HUMAN MOVEMENT

10

following description of these imaginary planes applies to the body in the

standing position with the weight equally distributed on the feet. jt\c\'L -The coronal or ventral plane jiyi des the bo dy into front^nd back parts and, when median, into front and back parts of equal weight but not of the

same design. The sagittal or Ja teral plane divides_the body into right and left p arts and, when median, into right and left parts equal in both weight and design—but only if the skeletal structure is free from defects and if body alignment is ideal. When there is bilateral symmetry of the body the median sagittal plane passes through the center of the sacral table, where weight divides to be transferred through the pelvis to either lower limb.

The

transverse or horizontal plane divides the body into upper and

when median, mto upper and lower

lower parts and,

parts of equal weight

but not of the same design.

When

these planes are median in an ideally balanced body they cross

each other

at the center of gravity of the

marks the crossing of the coronal and

body, while the line of gravity

sagittal planes.

Structural Features

The

following features of the structure are of primary importance in

function for weight support and

its

movement.

The Framework of Bones

Of the

integral parts of the

human body

involved in movement, the

bones are the firmest. They form the skeletal framework, protect the vital organs, support weight, and act as levers— the elementary mechanisms of movement. Their shape, size, and internal arrangement of cells vary in accordance with their ability to support weight, their movement potential,

and

muscular attachments. The bones are covered with a glistening periosteum, except at their articular extremities where, if freely movable, their

they are covered with hyaline cartilage. All bones are identified by name, either singly

— as

vertebra, humerus,

femur— or

in

combination as a unit —

as rib-case or thorax, trunk, shoulder girdle, pelvic girdle, pelvis, or spinal

column. Articulation of Bones

The

junction of any

name by which

a joint

is

two bones identified

is

The names of

called a joint or articulation.

may be

a combination of the

the articulating bones, as sternoclavicular (the juncture of the sternum, or breast bone, with the clavicle, or collar bone), atlantooccipital (the atlas,

or

first

sacroiliac (the

vertebra,

with the occiput,

sacrum with the ilium of the

or

base of the

skull),

or

pelvis). Occasionally the joint

STRUCTURAL COMPONENTS OF BODY ALIGNMENT AND MOVEMENT takes

its

name from

11

only one of the articulating bones, as femoral (thigh)

or humeral (shoulder); sometimes

it is

simply a

name

in

common

use, as

the elbow, knee, or ankle.

Ligaments Ligaments (76, 77) are strong fibrous bands which conjoin articulatall sides of the joint to give it strength and limit its motion. They vary in their cellular composition. Though flexible and pliable, only a few ligaments, such as the ligamentum flavum of the spine and ing bones on

Even these elastic continuous tensile stress, can lose their elasticity

the calcaneonavicular of the foot, are truly elastic. ligaments,

when under

and thus their ability to return to their normal length. This is evident in the "round back" and in the lowered arch of the foot at the junction of the calcaneous and navicular bones. Nonelastic ligaments, when continuously stretched, can be permanently lengthened and thus lose their ability to protect the joints. Examples of nonelastic Hgaments frequently overstressed are the deltoid ligament of the foot (Figure 34) and the medial or tibial coWaieral ligament of the knee (Figure 31). Cartilage in loints Cartilage, popularly called gristle, is a nonvascular structure which can serve several functions (76). Normally it is elastic; that is, it is compressible and extensible and can fully regain its normal shape and dimensions after release from pressure. This perfect elasticity, however, lasts

only so long as the pressures or loads imposed on

When

it

are small and of rela-

persistently uneven and of long duration, its elasticity may not only become impaired but may even be reduced to such a degree that it becomes impossible for it to return to its original shape when stress is removed. Because of this elasticity, a person actually is taller in the morning after a night of rest has allowed the cartilaginous discs between the vertebrae of the spinal column tively short duration.

pressure on cartilage

is

to return to their full size.

Hyaline cartilage, on the other hand, covers the articulating surfaces of freely

movable bones; hence

it

is

often termed articular cartilage.

It

of firm consistency, opaque, flexible, pearly blue in color, and contains no fibrous tissue. Hyaline cartilage also forms the extension of the ribs to or toward the breast bone or sternum. In doing so, it contributes greatly

is

to the flexibility of the rib-case.

White fibrocartilage is a mixture of white fibrous and cartilaginous tissue. There are three types of this cartilage in joints, the type depending on its location and function. 1.

Interarticular

fibrocartilage

occurs

in

interposed between the articulating surfaces of

various

disc-like

some bones.

It is

forms,

always

COMPONENTS OF HUMAN MOVEMENT

12

toward the center than at the cirmargins to surrounding ligaments or bone. Synovial membrane of the joint capsule is prolonged over it, thus distinguishing it both in structure and function from connecting fibrocartilage free

on both

surfaces, usually thinner

cumference, and attached at

(Figures 28

and

its

39).

hiterarticular fibrocartilage

found

is

in frequently

used

joints

which

are exposed to violent concussion, such as the knee, the acromioclavicular,

the wrist, and the sternoclavicular joints.

It

fills

in the space

between

the articulating ends of bones, permits greater depth of articulating surfaces, gives ease to

gHding movements, moderates the effects of great

pressure, reduces the intensity of shock to

and, finally, increases the potential for

which the

movement

joint

is

subjected,

in the joint.

Connecting fibrocartilage also is disc-shaped, but it is not covered with synovial membrane, nor are the bony surfaces it connects covered with hyaline cartilage. Hence, this cartilage adheres closely to the articulating bony surfaces, allowing only such shght mobility of the joint as can be obtained by the changing of its form. There is no movement between 2.

found between the bodies of the vertebrae of the spine as intervertebral discs (Figure 8), and between the pubic bones at mid-front of the pelvis — the pubic symphysis the bone and the cartilage. Connecting fibrocartilage

(Figure

is

5).

Marginal or circumferential fibrocartilage surrounds the outer margin of the articular cavities of rotary joints, such as the humeral and femoral joints. In doing so, it deepens the cavities and protects their rims. 3.

The Capsule of

a Joint

Freely movable joints are covered with an articular capsule whose outer

beyond their articular and its ligaments, this a white fibrous outer layer and the inner

fibrous layer attaches to the articulating bones surfaces. Like

capsule

an envelope surrounding the

made up

is

layer of synovial

synovial cavity.

normally

is

of two layers: membrane. The

It

known

as the

secretes a fluid, similar to the white of an egg,

which

sufficient only to

latter,

to

being a closed sac,

is

moisten and lubricate the synovial surfaces.

In an injured or inflamed joint,

enough

joint

however, the secretion

may

increase

cause pain.

Synovial

membrane

connective tissue,

fat,

often occurs in folds and projections

and blood

vessels.

Thus,

it fills

in clefts

composed of and crevices

within the

joint. It also covers tendons which pass over a joint within its capsule (as in the biceps brachialis muscle at the shoulder joint); sheathes muscle tendons which pass through fibrous and bony tunnels (notably in the

and forms bursae, or saclike cavities, within connective tissue between muscles, tendons, bones, and ligaments. It is a "friction reducer"

foot);

throughout the body.

STRUCTURAL COMPONENTS OF BODY ALIGNMENT AND MOVEMENT

13

Mobility of joints

The which

movement depends upon

role that a joint plays in

in turn

is

its

own

mobility,

a function of the design of the articulating surfaces. Artic-

ular

movement tends

and

third,

to be restricted first by muscles; second, by ligaments; by the design of the joint. The mobihty of joints is classified as

follows

Immovable

among most

(synarthroses). In

immovable

joints,

such as those that exist

of the bones of the skull, the bones are separated

cartilage, or a thin fibrous

by a layer of

membrane.

movable (amphiarthroses). Most slightly movable joints require a very strong connection between the bones. Consider, for example, the bodies of the vertebrae where contiguous bony surfaces are connected by fibrocartilage — termed a symphysis. Another example of a slightly movable joint is the articulation of the inferior ends of the tibia and fibula. Here the strength of connection is given by interosseous Hgament — termed a Slightly

syndesm^osis.

Freely movable (diarthroses). This

is

the most complex of

all joints.

In freely movable joints the articulating surfaces are expanded, completely

separated, and covered with hyaline cartilage. The entire joint is covered by a capsular sheath of fibrous tissue whose inside layer, synovial mem-

brane, secretes synovial fluid, as described above, to lubricate the joint.

The

joint

bones.

movable (2)

is

reinforced by ligaments which are attached to the articulating

The range joint

is

of

movement

limited only by

of the articulating bones in the freely (1)

the length of the articulating bones,

the relative tightness of muscles around the joint,

surrounding ligaments, and

(3)

the length of

its

(4) the form Muscles tend to restrict movement when they lose suppleness, as they do when they are overdeveloped ("muscle bound ') or habitually tight.

or design of the articulating sur-

faces.

Kinds of

Movement

in joints

Regardless of the kind of

movement normally involved, a joint is when there has been no movement

considered to be in a neutral position

of either of the bones forming the joint.

Movable joints permit the following movements (33, p. 298): Gliding, the simplest movement, is the sliding of one bone on the other. It occurs as a part of other kinds of movement, for example, with flexion and extension of the knee. It is the only movement between most of the tarsal bones of the foot and the carpal bones of the wrist. Angular movement increases or decreases the angle between one bone and another or one part of the body and another part. Rotation is a turning movement of bone around an axis in the joint; around its own axis (as in the rotation of the humerus or femur), around the

COMPONENTS OF HUMAN MOVEMENT

14

bone (as in the rotation of the first vertebra on the odontoid vertebra), or around an axis which is not even parallel second process of the to the long axis of the rotating bone (as in the radius around the ulna in the axis of another

forearm).

Circumduction

is

movement

bone

of a

to circumscribe a conical' space,

the base being the distal end of the moving part, the apex being the center

movement

of the joint (the

of the outstretched

arm while drawing

a circle).

Terms Applied to Movement of movement described above are combined in the different produce the following movements

The kinds joints to

Flexion (bending) decreases the angle between bones or body parts; extension

(straightening)

the

increases

angle.

Hyperextension

either

extends a bone past a neutral relationship at the joint (as in hyperextension of the knee) or

beyond that degree

of extension normally found (as in

hyperextension of the lumbar spine which can occur to a marked degree only

when

its

Rotation

spinous processes are shorter than usually found).

may be

turning of a bone inward or outward in one plane, as

humeral or femoral joint; or in various planes, as in the pelvis. may be to the right or the left, that is, clockwise or counterclockwise, respectively, in the horizontal plane; forward or backward in

in the

Pelvic rotation

the sagittal plane to increase or decrease the anteroposterior pelvis; or clockwise or counterclockwise in the coronal

right or left side, respectively. Rotation of the pelvis,

occurs in any of the true cardinal planes. This in

tilt

of the

plane to elevate the

however, seldom

phenomenon

is

explained

Chapters 5 and 17. Circumduction, defined above,

may be inward

or outward, that

is,

clockwdse or counterclockwise. is movement of a part toward the central movement away from the central line.

Adduction abduction

is

line of the

body;

Muscles Muscle contraction applies the force

to produce, retard, or prevent

movement of the bony levers. In any movement, muscles work — some more, some less, some sooner, some later — each in the degree necessary to attain the particular goal. Thus, muscles cooperate not only to

movement, but

also to allow

tion, stabilize the

trifugal) force,

movement

more

it,

control

its

speed and force, guide

produce its

direc-

central structures against outward-pulling (cen-

and even maintain equilibrium of the body

continually changes the distribution of weight.

as a

whole

as

STRUCTURAL COMPONENTS OF BODY ALIGNMENT AND MOVEMENT

15

The muscles or groups of muscles which take part in any movement depend upon the design and number of joints involved (directly or indirectly) in the movement. Hence, muscles may be classified functionally as follows: 1.

Agonists, or prime movers, effect the required

movement

of bone.

movement of bone or bones. Since muscle acting on a bony lever is matched by muscle which moves the bone in the opposite direction, muscles may be either agonists or antagonists depending on the direction of movement. 3. Synergists prevent other muscles from performing undesired move-' ments. They are essential associates of the prime movers; they cannot be 2.

Antagonists lengthen to allow the

practically every

voluntarily eliminated from any 4. Stabilizers

movement.

maintain a bone or bones in a given position despite a con-

That force may be provided by another, contrary- acting musan outside force, or both. Muscles may perform any of these four functions at different times. For further discussion of muscles, see Chapters 12-14. flicting force.

cle,

The Nervous System

The nervous system provides extremely different parts of the body, correlating

processes.

here, for

Its

it is

all

communication among

and integrating various bodily

movement

is of great importance self-movement (see Chapter 15).

function in relation to

an integral part of

fast

Physical Laws and Principles of

Mechanically, the

Mechanics

human body

same physical laws and

is

a hving machine.

is

operates under the

principles as inanimate structures.

human locomotion is possible without nor

It

No

study of

a knowledge of the laws of mechanics,

an evaluation of the efficiency of a movement meaningful unless

it

takes into consideration the fundamental laws and principles of mechanics.

movement, close adherence to these laws results in less and stress and greater range and ease of movement. Mechanics, however, must not be applied only to the relation of bodily movement to outside objects; it is just as crucial to internal structural mechanisms: the alignment and relationship of bones which are dominant in the upright position and in the movement of each person (Chapters 16 and 17). This concept is basic to the philosophy of this text; it has also proven to be a part of the movement patterns used to promote more efficient neuromuscular coordination (Chapters 17 and 21). Consequently, a simple definition of key terms and laws is essential to our understanding of the text which follows. A machine is a device that converts energy into work to accomplish some purpose. To perform, the machine must receive energy from some outside source. It cannot create energy, nor can the amount of work it performs exceed the amount of energy it receives. If its work were equal to the energy received, it would be 100 percent efficient. In fact, however, since all machines must overcome friction, none is ever totally efficient. There are six simple machines, of which the lever, the machine for movement of the human body, is one. Other simple machines are the pulley, wheel and axle, inclined plane, wedge, and screw. These six machines may be still further reduced to two: the lever and the inclined plane. The pulley and the wheel and axle are only modified levers, while the screw and wedge In performing any strain

are modified inclined planes.

Energy

16

is

the capacity to do work;

it is

that

which may be converted

AND

PHYSICAL LAWS

PRINCIPLES OF

Energy stemming from the position of a body

into work.

or potential energy; that resulting from motion

is

MECHANICS is

17

called stored

kinetic energy.

Terms Relating to Force Force

is

the cause (a push or pull) which produces or changes accelera-

The unit of force is one dyne, the amount necessary to acgram of free mass 1 cm. per second. The effects of force can

tion of a body.

celerate 1

be seen,

felt,

and measured; but force

ness of force within his body

is

itself

cannot be seen. Man's aware-

derived, perhaps unconsciously, from the

sensory impulses within muscles as they occur with movement.

Work

is

the product of a force acting through a given distance, always

The basic unit of work is 1 erg, which is equal dyne per cm. It is, however, the body or agent that exerts the force which does the work, and in man this agent is muscle. Power is the rate at which a body or agent works; it is the number of units of work performed per unit of time. The basic unit of power is one in the direction of the force. to 1

erg per second. Gravitation

is

the force of attraction that every particle of matter in the

universe has for every other particle. of the bodies

The

force

and inversely proportional

is

proportional to the masses

to the square of the distance be-

tween them. Gravitation is a function solely of mass; it bears no relation to other qualities of a body such as temperature or molecular condition. It is

a general, not a selective force.

It

accounts for the motion of planets

in relation to the sun.

Gravity, identified by the letter g,

the earth and

all

bodies on or above

gravitation. Gravity's effect

weak 4000 its

is

is

its

the force of attraction between surface.

It is

a particular case of

strongest at the earth's surface;

it

is

very

miles beyond that surface. Indeed, at an altitude of 3 to 5 miles,

reduced effect begins

to interfere

with the

ability of

man, a

terrestrial

animal, to function effectively.

The force of gravity is capable of giving an object acceleration equal 980 cm. (32.2 feet) per second. All bodies fall with the same acceleration when the only force acting on them is gravity. On the other hand, when a man jumps or throws an object, or when a space craft rises from its launch pad, gravity has to be overcome. Thus, the rate of acceleration needed by an object to cause it to rise must be greater than gravity's pull. to

man to earth. It is the primary force to be considered alignment of the skeleton of the body in the upright position.

Gravity holds in the study of

Weight

is

the measure of the mutual attraction between the earth and its surface. It is gravitational attraction which gives us

a body near or on

weight and a sense of which way

is

down; weight

is

the measure of the

COMPONENTS OF HUMAN MOVEMENT

18

force with

which gravity

body can reach a

body toward the center of the earth. No weightlessness unless it is too far from the earth

pulls a

state of

to experience the p\ill of gravity.

The Play of Force on a Body

The center of gravity

of an object or

body

is

that imaginary point about

which all parts exactly balance each other; it is that point from which a body can be suspended in any orientation without tending to rotate. In the human body, its approximate location is in the pelvis just in front of the upper part of the sacrum at about 55 percent of the height of the individual (76). Various factors influence the location of this center of weight at any one moment. The line of gravity (or line of weight) is an imaginary vertical line which passes through the center of gravity. It may be considered as the vertical axis of a structure.

Equilibrium of a body exists

when

the

sum

of

all

forves acting on

it is

zero.

when any change

body raises back to its original position. The more nearly the line of gravity passes through the center of the base, the more stable the equilibrium. A frequently cited example of stable equilibrium is a cone resting on its base. Unstable equilibrium exists when any change in position of a body lowers its center of gravity. When disturbed, the body will fall away from its original position. A cone resting on its tip and the skeleton in an upright position are both examples of unstable equilibrium. Neutral equilibrium exists when any change in the position of a body does not affect its center of gravity. Examples of this phenomenon are a ball, a funnel, or a cone resting on its side. Mechanical balance exists when the arrangement of the weight of the structure itself is such that stable equilibrium is maintained without outside help. The mechanical balance of a structure becomes increasingly stable as the distribution of its weight meets the following criteria: (1) a broad, level base for support; (2) equal distribution of weight around, and as close Stable equilibrium exists

body

in position of a

center of gravity.

to,

the line of gravity as possible; (3) a line of gravity centered in

and

f

tipped, the

its

If slightly

weight as close

will fall

its

base;

base as possible. These four principles serve good alignment of the upright human body. Stress is the cohesive force by which the particles of a body resist an external load that tends to produce an alteration in the form of the body. The five types of mechanical stress are described below. Of these, compressive and tensile stresses are the least harmful to the form of the bones of the skeletal framework as it functions in the support of weight. (4)

to the

as guides in determining

PHYSICAL LAWS 1.

Tensile stress, or tension, to stretch a structure

is

AND

PRINCIPLES OF

MECHANICS

19

produced when external forces tend

without interfering with

its axis.

Jensile stress

produced in bones as muscles pull upon them. Compression (pressure) stress is produced when forces tend to compress a structure or push its particles closer together without interfering with its axis. All bones experience compression stress when they are supporting body weight. Shearing (sliding) stress is produced when forces tend to cause the particles in one section of a structure to slide over those of an adjacent section, thus interfering with its axis. This type of stress is experienced in any Class I (see Chapter 4) bony lever when it is not in mechanical balance as it supports weight. Torsion (twisting) stress is produced when forces act in opposite directions around the axis of a structure without interfering with its axis. Like shearing, this stress occurs in bones which consistently deviate from good alignment in the upright position. Bending (transverse) stress is produced by forces which tend to bend a structure. This stress combines tensile, compressive, and shearing stresses. It is the most harmful of all stresses because it interferes with the ability of the structure to support weight. In lateral curves of the spine, the vertebrae and discs involved experience bending stress which, if persistent, ultimately results in change in their form.

is

2.

3.

4.

5.

bone are concentrated and arranged architecturally to meet of forces imposed upon them. All stresses are present and experi-

The cells the stress

of

enced in bones as movement takes place, but such stresses are constantly changing and therefore not harmful. Steindler (76, 77) states that the architectural response of bone to mechanical stresses merely approaches, but never completely conforms with, accurate engineering calculations that can be appHed to inanimate structures. This lack of conformity is an important difference between animate and inanimate structures. Strain apphes to any change of shape, volume, or both in a body.

It is

the result of excessive and/or long-continued stress. Elasticity

tortion

is

when

that quality of a

stress

is

removed

body which enables

it

to recover

from

dis-

(70).

body which enables it to be bent, turned, or twisted without experiencing measurable deformation or being broken, and with or without returning itself to its former shape. Flexibility

is

that quality of a

Suppleness, applied to muscles, characterizes the abihty of muscles range of voluntary movement in the joint whose

to lengthen to allow a full

Lack of suppleness in muscles restricts the normal range of movement allowed by joint design and ligamentous reinforcement.

position they influence.

In "muscle-boundness,"

many muscles

lack suppleness.

COMPONENTS OF HUMAN MOVEMENT

20

The term

tension

is

often applied to a person or to a particular portion

and a tense neck. This means that many They are experiencing unnecessary strain, and the suffering person seldom knows how to reduce or eliminate that strain except by changing his body position and/or activity. This muscular tension may result from emotional strain, pressure of work, drive for accomplishment, anxiety, worry, or — finally — false ideas about posture and movement, such as the "high chest" as a mark of his body, such as tense shoulders

of his muscles are engaging in nonpurposive, incessant contraction.

of "good posture."

How Weight, either in the

Weight

is

human body

Supported

or in mechanical structures, can be

supported or held in place in one or a combination of three different ways:

by sitting or resting on something, (2) by hanging from something, and by being braced in place. In the human body, for example, in the upright position vertebral bodies sit, ribs hang, the shoulder girdle both sits and hangs, and the sacrum is braced in place in the pelvis. The way in which the weight of each of the bony levers is supported necessarily affects efficient skeletal alignment. In Chapter 16 the manner in which the weight of the various skeletal parts is supported enters into the discussion of each (1)

(3)

part.

Newton's Three Laws of Motion

The Newtonian laws function the key to in

all

in all terrestrial mechanics.

man, machinery, and mechanical

Newton's

They are

motion, establishing the conditions for motion and equilibrium

First

structures.

Law

Every body persists in its state of rest or uniform motion in a straight unless it is compelled by some force to change that state. This is often called the law of inertia. When man and his space ship are far enough from earth, inertia and gravity keep the space ship in orbit, but when the space ship is propelled by rocket in a definite direction toward the moon beyond the pull of gravity, liney

it is

inertia that enables the ship to travel in a straight line

toward the moon.

Newton's Second Law

The rate of change of the momentum of a body is proportional to the it and is in the direction of the force. Here, momentum is defined as the product of mass and velocity. This law can be seen in both the starting and stopping of running, where the force acting on the body is muscle contraction.

force acting on

PHYSICAL LAWS

AND

PRINCIPLES OF

MECHANICS

21

Newton's Third Law Action (thrust) and reaction (counterthrust) are equal and opposite. This law calls to

mind the

firing of rockets to

lift

a space ship from

its

launch pad. Likewise, when one turns on a garden hose suddenly, the reaction of water shooting outward makes the hose try to move backward in

The recoil of a gun into one's shoulder when it is fired is another example of reaction or counterthrust. Action and reaction are ever-present in man's activities — for example, in diving from a spring board; in jumping, running, or walking; and in all sports and dance. The downward thrust of the body weight in any position the body may assume is always met by counterthrust from the earth. In the standing position, at the level of any weight-supporting joint in the body, the thrust of weight above is met by counterthrust from below. The ability to keep the axis of thrust and counterthrust centered in weightsupporting joints is the secret of efficient posture and movement, attained only through efficient habits of neuromuscular coordination.

one's hand.

The Lever as the Machine for Movement

The machinery

for

movement

human body

of the

bones, joints, muscles, and the nervous system. sponsible for

may

movement

act as a lever, as

is

consists primarily of

The machine

directly re-

the lever. Every movable bone of the skeleton

may

the various units of the skeleton — the head,

— when

they move as a whole. At least 107 single and form can be identified in the skeletal structure. Most of these are used in any pattern of bodily movement— some being stabilized in position, others moving synchronously, and still others working successively to create a flow of movement. Thus, movement of the human body results from simultaneous, harmonious, and successive operation of a multitude of bony levers. It is indeed a complex affair. rib-case, pelvis, or foot

bony

levers of varying length

The Lever Defined

The lever is a relatively rigid bar, either straight or curved, which is supported at a fixed point, the fulcrum, and is capable of rotary motion around that point. It performs work when force is applied at some point on the bar

move weight or resistance human body, the fulcrum of to

at

another point on the bar.

is

the bony lever is the joint, and it here that the axis of rotation of the lever is located. Muscles attached

to

some point

In the

desired

or points on the

movement

bony lever furnish the force either

of the lever or to resist undesirable

to

produce

movement which

may produce. Motor nerve messages stimulate the muscles; in fact, the motor nerve and the muscle are functionally intergravity or other forces

dependent. Whereas the source of motion lies in the nervous system.

lies in

the muscle, the cause

Classification of Levers

There are three classes of

levers,

location of the fulcrum or axis of 22

which are defined by the

movement

(F),

relative

the weight or resistance

THE LEVER AS THE MACHINE FOR MOVEMENT

23

The lever turns or pivots on the fulcrum. In the Class aWays between and P; in Class II, is alw^ays betw^een

(W), and the force (P). I

lever,

F and

F

W

is

W

P is

always between F and W. The force arm (PA) is the perpendicular distance from the line of action of force to the fulcrum: likewise, the weight arm (WA) is the perpendicular distance from the line of action of weight to the fulcrum. In the movement of bony levers, these perpendicular distances may coincide momentarily P; in Class

III,

itself, as shown in Figure 2 As the lever moves, the angle of application of both force and weight changes; as does the relative length of the force and weight arms. In Figure 3, PA and WA do not coincide with the lever as it is positioned. The vertical dotted lines indicate the line of action of P and W. Note that if the angle of the lever were changed, the angle of the line of action of P and Win relation to the lever would also change. In Figure 3A, in Class I, the relative length of the weight and force arms can be changed by moving the fulcrum or axis of movement; in Class II, the force arm is always longer than the weight arm; in Class III, the force arm is always shorter than the weight arm. In Figure 3B the muscle attaches to the lower arm (the lever) much closer to the elbow (the fulcrum) than is shown in the illustration. With the lever in this position the weight arm coincides with the lever, but the force arm does not.

with the bony lever

Laws of Mechanics Applied to the Lever Force can produce translatory a point of the

moving body

CLASS

is

(in

W

Figure

2.

The

Hi

levers in horizontal position, in

the lever arms.

w

li

t CLASS

if

movement.

^

I

r CLASS

a straight line) or rotary motion

fixed to constitute an axis of

^

if 4'

which the force and weight arms coincide with

COMPONENTS OF HUMAN MOVEMENT

24

CLASS

CLASS

C.

CLASS

B.

I

II

III

CLASS

III

FLEXOR MUSCLE

I

Figure 3 (A,B,C). The levers in a slanted position, showing the location of

(D ) The lower part

The movement around an axis can occur is at gliding

knee

is

PA and WA.

as a Class III lever.

of levers in the

fulcrum or

human body

tends to be rotary motion

The only place

translatory motion which allow only gliding motion, or in a joint where rotary movement, as it is in flexion or extension of the

at the

joint.

joints

a part of

(see p. 81).

Moment is

arm

of the

of Force (Torque]

The moment of force, or torque, that which tends to produce rotation, defined as the product of force times the length of the force arm. When

the

moment

of force

moments

of the

the lever

is

of weight, that

is,

when

the

in balance.

An example when

moment

equal to the

is

two forces around the fulcrum are equal and opposite, of equal

the weight

it

found in the human vertebra is balanced around the The axis of weight thrust is then centered

moments

supports, plus

center of the vertebra below

it.

of force its

own

is

weight,

in the joint.

Mechanical Advantage

The mechanical advantage of a lever is the ratio of the length of the arm to the length of the weight arm. During movement, as the length the force arm increases the relation to the length of the weight arm, the

force of

mechanical advantage tage

is

is

increased; as

decreased. This applies to

The

location of weight

all

and force

it

decreases, the mechanical advan-

three classes of levers.

fulcrum in the three mechanical advantage. When

in relation to the

classes of levers determines their relative

THE LEVER AS THE MACHINE FOR MOVEMENT

25

equal in the three classes, a Class II lever always has the greatest mechanical advantage because its force arm is alw^ays longer than its w^eight arm. Likew^ise, a Class III lever has the smallest the length of levers

is

mechanical advantage because weight arm. Efficiency of a

The

force

its

arm

is

aWays

shorter than

its

Machine machine

efficiency of a

is

work done by

the ratio of mechanical

the machine to the work done on the machine; the two quantities differ by the amount of work used to overcome friction. Efficiency

is

usually expressed in a percentage (always less than 100

percent because of

friction).

Expressed as a

ratio, efficiency

use u wor

=

•f

total

Steindler stated that "walking, which

1

1

work

our highest motor accomplishment, has in normal individuals an efficiency index of 35 percent, a very high is

figure for a combustion engine" (76, p. 7).

The

The

Joint as the Fulcrum for

joint acts as the

Movement

fulcrum for movement of a bony lever and, by its which a bony lever may move. Thus,

design, determines the directions in

the kinds of

movement

(flexion, rotation, etc.) that a

depend on the design of the joint which serves The ball and socket joint allows movement the fulcrum (humerus, femur) in

all

as

its

bony lever can make fulcrum.

of the lever for

which

it is

directions. In contrast, the hinge joint

movement in one plane and so only in two directions. The and freedom of movement allowed by joints throughout the body varies between these two extremes. (elbow) allows

direction

The Bones as Levers

Bony its

levers are of

many

shapes, sizes, and designs, each of which has

counterpart in buildings and other

man-made

structures.

Among

these

designs are the arch, beam, cantilever, and snowshoe found in the pelvis;

the truss and column found in the spinal column; the suspension bridge

found in the shoulder girdle in the four-legged position; and the wheel with its hub at the pelvis and its spokes in the spine and the upper and lower extremities. These skeletal designs provide for weight support, shock absorption, range of movement, and stability, often wdth minimal muscle work.

By noting the contribution which the particular design of bony levers makes to stability and movement, the reader will understand better the possibilities for movement open to him and the various patterns of movement he may create and employ in his activity.

COMPONENTS OF HUMAN MOVEMENT

26

Muscle Contraction: The Force Which Moves Bony Levers

The

and man-

contractile fibers generate the force to shorten the muscle

thus pull (never push) the bony lever. Muscle

made machines Any bony

is

a "pull" engine; most

are "push" engines.

lever

must have

at least

two muscles attached

to

it

to pull

it

in opposite directions in one plane (a situation found only in a pure hinge

But, of course, most bony levers can

joint).

move

in a

number

of directions

However, the bony lever which moves in more directions does not necessarily have a correspondingly greater number of muscles attached to it, because the increase in directions of movement is accomplished by the synergistic (cooperative) action of a smaller number of muscles (see p. 149). This is an example of how nature economizes. The angle of attachment of muscles to bony levers varies throughout the body, but no muscle in its entirety is ever in perpendicular relationship to a bony lever. The pectoralis major muscle attaches to the humerus on in various planes.

almost a perpendicular angle, but this relationship of

movement, the angle

is

unique. In the progress

bone changes, either to increase the force arm of the bony lever. This accounts

of the muscle to

or decrease the length of

for difference in the ease of

movement

at various stages of its progress.

At any stage, the more acute the angle of attachment of muscle to bone, the less rotary force the muscle can exert on the bony lever. All

bony

muscles attaching to a bony lever must have their origin on another

lever, usually

one that

is

closer to the center of the body. This

bony

lever must be more stable than the moving lever because of greater weight, muscle contraction, or both. To visualize how complicated the action of levers in a pattern of movement is, picture the different bony levers, from the most distal to the most central in the trunk, engaged in a movement pattern — and then realize that these levers must be subjected progressively to greater stabilization as they are located nearer the center of the body.

The

must coordinate muscle action toward this end movement. In doing so, it is influenced by many and continually changing ingoing messages from the procentral nervous system

in response to the individual's goals for

prioceptive senses.

Operational Effects of the Various Bony Levers

The arrangement of weight (or resistance) and force in relation to the movement in the three types of levers enables each to make a particular contribution to bodily balance and movement. Whether the body seeks stability of position, force for movement, or a large range of movement, nature has provided the right lever for the task. fulcrum or axis of

THE LEVER AS THE MACHINE FOR MOVEMENT

Class

I

The

27

Bony Levers Class

I

be stable because of the location of force on These levers depend on bony arrangement, not

levers tend to

either side of the fulcrum.

the force of muscle contraction, for their stability.

When

weight balances weight on either side of the fulcrum, muscle work is not needed to maintain balance of the lever. Instead, the weight of the bony lever, plus the weight

superimposed on

The

teeterboard. side of

it,

are centered at the joint which serves as

stability of the Class

its

I

The seesaw balances

fulcrum

is

the same.

its

fulcrum.

lever can be illustrated with a seesaw or

If

in mid-air

when

the weight on either

one end of the seesaw

is

heavier than

the other, however, force must be added to the other end to maintain the

board

in a

balanced position. In the body,

when such

ance, muscle contraction adds the force to maintain Class I Skeletal Levers. Throughout the body

a lever

is

out of bal-

its stability.

where one bone

rests

on another in the upright position, it relies on the Class I lever, using the bone below it as its fulcrum. From the head downward first-class levers are: the head on the atlas, each vertebra on the vertebra below it, the fifth lumbar vertebra on the sacral table, each half of the pelvis on its femoral head, and — in each lower limb — the femur on the tibia, and the tibia on the talus of the foot.

The problem of skeletal alignon the balance of the Class I levers

Class I Levers in the Upright Position.

ment

in the upright position focuses

from head to foot. Since the body is dynamic— never static— there invariably must be some muscle force applied to weight-supporting levers to maintain their stability. The only aid to, or substitute for, such muscle work is ligamentous support at the joints which, if it persists on the same side of the joint over a period of time,

may

finally result in

undue ligamentous

strain and, all too often, to injury during strenuous activity.

When the alignment of

the weight-supporting levers produces close con-

formity of the skeleton as a whole to principles of mechanical balance (see

muscle work on the lever arms passes back and forth between opposis threatened in various directions. When a firstclass lever deviates from balance persistently — in the same direction at the same level or levels of the body —muscle work must likewise be applied persistently on one arm of the lever to maintain its stabiHty. p. 18),

ing muscles as balance

Increased, repeated muscle

developed muscles. In Class

I

work

results, of course, in larger,

more

bony levers, an increased work load results

muscles of relatively greater development in proportion to the degree and direction of persistent deviations from mechanical balin a pattern of

ance.

The

large

work load imposed on muscles attached

to

one arm of an

COMPONENTS OF HUMAN MOVEMENT

28

unbalanced bony lever becomes still greater as the angle of attachment of these muscles to the lever arm grows more acute. When this happens, the muscle must work still harder because the mechanical advantage of the bony lever diminishes. Throughout the body, deviations from efficient alignment of weightsupporting Class I bony levers result in diminution of the mechanical advantage of these levers in movement; we shall return to this problem repeatedly in our study of bodily balance and movement. Class

II

Bony Levers

The Class II lever meets the need of force for movement. Its mechanical advantage is the greatest of the three levers because its force arm is always longer than its weight arm. Thus it can move more weight, but through a shorter distance and with less speed than a Class III lever can.

human body must be lifted by muscle force — as and jumping — a second-class lever is always there to do the work. The foot as a whole is such a lever; its fulcrum is at the ball of the foot and its muscle force is applied at the heel. Body weight rests on the lever at the talus, the uppermost bone of the foot. Kinesiologists disagree as to whether the foot can be classified as a Class II lever. Certainly, in order for it to be so classed, it must be used as such. The foot is not a second-class lever when the heel is raised from the ground by the act of leaning forward. In this situation, the movement is that of the leg as a first-class lever rotating on the ankle joint as the ful-

When the weight

of the

in walking, running,

crum. The line of gravity then

falls

through the front of the

foot,

but not

itself has been used as a lever of any class. As the heel by contraction of the calf muscles, the foot becomes effective as a second-class lever just when force is most needed in propelling the body upward and forward. When the foot is not engaged in weight support, as in any hanging position, it acts as a third-class lever with its fulcrum at the ankle joint. In walking, running, or leaping, the foot alternates from a second- to a third-class lever. When the entire foot supports the body weight in standing or, momentarily, in walking, the work of muscles to maintain the integrity of the foot against changing direction of weight thrust is very complicated. Under such circumstances, most of the 26 bones of the foot probably func-

because the foot

is

lifted

tion as third-class levers; but the foot, as a whole, in standing

is

not perform-

ing as a lever.

Class

III

The

Bony Levers

Class III lever favors speed and range of movement. The angle muscle attachment is more acute than that of first- and second-class levers. As a result, it has the least mechanical advantage of the three levers.

of

its

THE LEVER AS THE MACHINE FOR MOVEMENT

Even

so, its

predominance

in the

29

body provides the following important

advantages for man: 1.

A

greater range of

movement with

relatively little shortening of

muscles. 2.

Greater speed of movement due to the relatively long weight arm — of great advantage in the use of the

arms and

legs.

3.

Decreasing muscle work as the range of movement is being completed, since the weight arm shortens rather markedly in relation

4.

Less muscle bulk around joints, since muscles or their tendons

arm.

to the length of the force

close to the joints, giving

lie

them a greater compactness and more

graceful lines.

Muscles attached to third-class bony levers are especially suited for by the arrangement of their contractile fibers (see Chapter 12). But nature employs still other devices than muscle fiber arrangement to increase the effectiveness of muscle work. Some of these are cited below: Friction which increases resistance to movements is minimized by lubrication in the joints, between muscle groups, and between muscles and bone. Sometimes overusing the muscles results in insufficient lubrication, their task

and conditions such as teno-synovitis or bursitis appear. When they do, movement becomes painful and rest is advisable. The "frozen" shoulder joint is an example of insufficient lubrication of the joint. In this situation, movement becomes painful and restricted, but improvement occurs with gradually increased movement, regardless of pain, in all directions allowed by the joint design.

The

stretch reflex, a principle of function applicable to

the ability of the stretched muscle to

p. 144), increases

force

arm

is

shortest

and the mechanical advantage

muscles (see

all

move when

of the

the

bony lever

is

greatly diminished. In the third-class lever the stretch reflex provides extra contractile force to the

muscle when

it

is

most needed. The preparatory

of the pitcher before he delivers a ball and

backward movement of the arm the backward movement of the leg of the football player getting ready kick the ball are two familiar examples of this stretch reflex.

to

A mechanical device similar to the pulley increases the mechanical advantage of some of the third-class bony levers by providing a longer force arm

for the

1.

The

bony

lever.

Examples

of this device are:

external malleolus under which the peroneus longus muscle

loops on

its

way from

the fibula to the inside of the bottom of the

foot. 2.

on the pelvis over which the obturator internus muscle passes from the inside of the obturator foramen to the

The

lesser sciatic notch

inside of the greater trochanter of the femur.

COMPONENTS OF HUMAN MOVEMENT

30

3.

4.

The femoral condyles

end of the femora over which the hamstrings pass from the tuberosity of the ischium to the upper part of the tjbia and fibula.

The

patella at the

of the distal

knee over which the quadriceps extensor muscle its attachment on the tibial tu-

passes from the pelvis and thigh to berosity.

Once we understand how bony levers work, we can appreciate the importance that habitually efficient skeletal alignment holds for the efficient action of muscles in the many positions and movement patterns used in all activities. It is not enough merely to know the pattern of movement of the bony levers; it is equally important to evaluate and interpret the pattern against the background of the mechanical design and capabilities of the

human structure. movement of the

In the

dance,

it is

doubtful that judgment of

its artistic

value has any basis in scientific facts of anatomy, mechanics, and principles of

muscle function — even though

its

performance does.

On

the other hand,

competitive athletes must pay attention to the principles of mechanics in the patterns of

movement

of the

body

if

they wish to win.

And

yet the

importance of efficiently balancing the weight-supporting first-class levers is rarely given anything but scant attention in activity teaching. The author has worked with many athletes and dancers, all of whom were intimately acquainted with the specific patterns of movement of their particular activities. These athletes and dancers greatly improved their performance through improvement in skeletal alignment, that is, through improvement of the internal mechanics of the body. Possibly the most deleterious effects of inefficient postural alignment

among participants in the dance and competitive sports. Emphasis on basic principles of mechanics, both internal and external, in all activities, as well as in everyday movement, results in both a longer period of activity in one's chosen career and fewer

are knee and back injuries, especially

backaches among our adult population.

5 ^^^^^^^^^^^^«^^^^^^^

The

The

pelvis

is

uniquely stable because of both

its

Pelvis

relation to the line of gravity

and its central location in the body. It may be compared to the hub of a wheel with the upper extremities and spinal column forming spokes, tied to it through bone and muscle. Correspondingly, the lower extremities form two other spokes, articulating directly with it at the femoral joints. As in the hub of a wheel, the center of gravity is located within the pelvis; also like the hub, it is the center of control of movement. Muscles reach out from the pelvis to the most distant parts above and below. They may reach directly as individual muscles, or indirectly, as a series of muscles which are given continuity through interdigitation and/ or fascial structures binding them together. The design formed by the alignment of these muscles, somewhat like an X on the front and back of the trunk, indicates nature's provision for coordinating the posite as in

movement

of op-

arms and legs— a mechanical advantage which conserves energy, walking and running.

Functions of the Pelvis

The

pelvis has four

viscera; (2)

it

main

functions: (1)

it

supports and protects the

gives origin to muscles inserting on the trunk, lower limbs,

and proximal portion of each arm

(the latissimus dorsi muscles); (3)

sorbs the shock of weight thrust in

movement; and

(4)

it

it

weight of the trunk and upper extremities to the lower limbs. The three functions are an integral part of

all

Bones of the

ab-

transmits the last

movement.

Pelvis

At birth the pelvis is composed of various separate bones. The wedgeshaped sacrum forming the back of the pelvis was originally five separate bones, each presenting in general the component parts of the movable

COMPONENTS OF HUMAN MOVEMENT

32

ISCHIUM

Figure

4.

tabulum

The to

three bones — the ilium, the ischium, and the pubis — which unite in the ace-

form the os innominatum.

vertebrae of the spine. Considered as one bone, however, is

its

concave from above downward and shghtly so from side

inside surface to side. This

shape increases the area within the pelvis. The three to five bones of the coccyx below the sacrum usually fuse into one bone but remain mobile in relation to the lower

On

end of the sacrum

until late in life.

either side of the sacrum, three separate bones of very irregular

shape— the

ilium, the ischium,

and the pubis — iuse

front of the pelvis, the os innominata (see Figure 4). ter

to

form the sides and

They meet

at the cen-

depth of the socket, the acetabulum, which articulates with the femoral

head.

Thus the

pelvis of the adult

is

made up

of three large bones:

two os

innominata which are alike on either side and front, and the sacrum with the coccyx at back.

Design of the Pelvis

The design

and flexibility. It which is closed at the bottom by muscular structures. The pelvis of the male usually has less flare to its sides and greater depth to the acetabula, with less distance between them (see Figure 5). Other factors being equal, this latter design favors greater speed in running than can be attained by the female. According to Crelin (16), androgen, a male sex hormone, induces the development of the male type of pelvis. Prior to the emergence of this hormone, sexual dimorphism does not exist. is

of the pelvis favors both weight support

a bowl-like structure with flaring, high sides,

THE PELVIS

33

The Pelvic Arches

The

pelvis

may be

divided into two arches by a coronal plane through

the centers of the acetabula. In the posterior arch, the upper three sacral

vertebrae form the keystone of the arch, while pillars of thickened bone

lower part of the ilium constitute the two sides. The sturdiness of arch makes it well suited to handle the pressure of weight as it is trans-

at the this

ferred from the sacral table to the heads of the femora in standing, or to

the ischial tuberosities in sitting.

The

anterior arch

is

composed

of

two

bars of bone from the pubis on either side, one of which meets the pillars

LUMBOSACRAL JOINT FIFTH

LUMBAR VERTEBRA

SACRUM

SACROILIAC JOINT ANT. SUP. ILIAC

SPINE ANT. INFER. ILIAC

SPINE ILIOPECTINEAL

EMINENCE PUBIC

SYMPHYSIS

i

PUBIC TUBERCLE

I

OBTURATOR FORAMEN ISCHIAL

TUBEROSITY

ACETABULUM Figure 5 (A).

An

dravm from the x-ray photograph of a submale pelvis, drawn from the x-ray photograph of a subject 90 years of age, was a mountain climber in his youth.

ideally balanced female pelvis,

ject in the standing position. (B)

A

in the lying position. This subject,

COMPONENTS OF HUMAN MOVEMENT

34

of the posterior arch at the center of the acetabula. This design adds to

the strength and stabiHty of both arches.

The Rims

The upper and lower rims of the pelvic bowl are very different in formaThe upper rim is lowest in front at the horizontal upper borders of the pubic bones from acetabulum to acetabulum, somewhat higher and tion.

much

thicker at the top of the sacrum at the back, but highest on the sides

The lower rim is formed by three downward prosacrum with the coccyx at center back, and the two tuberosities of the ischia at the junction of the sides and front of the pelvis. These extend to a level lower than the end of the coccyx, thus protecting the coccyx from weight pressure in sitting. There are five notches, or arches, between the downward projections: the pubic arch at mid-front, and the greater and lesser sciatic notches on either side between the ischial tuberosities and at the crests of the ilia.

jections: the

the sacrum.

The

whole tends to have thickened bone where it is needed and transfer of weight, but a minimal amount of bone otherwise. This design reduces the weight of the pelvis and gives it resilience for shock absorption in movement. pelvis as a

in support

The Anteroposterior

Tilt

(The Pelvic Inclination)

As stated above, the upper rim

of the pelvis

is

lower in front than in

back. In the upright position, a plane which connects the upper edge of the pubic symphysis with the posterior inferior spines of the of inlet of the pelvis) forms an angle of

and an angle

of

50

to

30

to

ilia

40 degrees with a

(the plane

frontal plane,

60 degrees with a horizontal plane.

Foramina

The

front of the pelvis

is

marked by two

large openings, the obturator

foramina. Each

is formed by bars of bone (rami) belonging to the pubis and ischium. Two other foramina on either side of the pelvis are formed by ligaments which close the sciatic notches mentioned above. Blood vessels, nerves, and muscles pass through the sciatic notches. Most notably, the sciatic nerve and the pyriformis muscle pass through the greater sciatic notch. Only nerves and blood vessels pass through the obturator foramina. They are laced over with fascia somewhat like a snowshoe, and their circumference provides attachment for the internal and external obturator

muscles. Articulations of the Pelvis

There are three structures

— the

and three with adjoining lumbar vertebra.

articulations within the pelvis,

femoral heads and the

fifth

THE PELVIS

35

Articulations wittiin the Pelvis

The design

between the three parts of the pelvis movement. The two sacroiliac joints occur at the junction the iha with the upper lateral part of the sacrum on either side. The 6i the articulations

allows only slight of

lie approximately on a level with the posterior spines which appear as bony prominences (dimples in case of obesity) on the upper back surface of the pelvis. The articulating surfaces of the sacroiliac joints are very irregular, but their irregularities conform to each other nicely. They limit motion, however, to a slight, gliding rotation of one bone on the other. The third joint within the pelvis is found at the mid-front — the pubic symphysis. Here the two pubic bones are joined by connecting fibrocartilage whose elasticity allows for slight movement between the two bones. There is no movement between the fibrocartilage and the pubic bones on either side.

tops of these joints of the

ilia

In studying

many

anteroposterior x-ray photographs of the pelvis in

the standing position (63, 80), the author frequently saw differences in height of the right and

left

pubic bones at the pubic symphysis. This

dif-

ference indicates that a persistent rotation at one of the sacroiliac joints

Which was not revealed by the measure-

tends to enter into the pattern of asymmetry found in the pelvis. sacroiliac

ment

was involved

in the pattern

data.

Articulations with Adjoining Structures

The

articulations of the pelvis with adjoining structures occur at three

sacrum with the fifth lumbar vertebra (the lumbosacral joint), and the acetabula with the heads of the femora (the thigh or femoral joint)

places: the

(see Figure 5B.)

The sacrum

articulates with the fifth

lumbar vertebra

in three places:

means

of a connecting

the sacral table with the body of the vertebra by fibrocartilage or disc,

and the two superior

articular facets at the top of

the sacrum with the inferior articular facets of the vertebra. These latter

two

movement of a gliding nature, but the former movement through change in the shape of the disc. The movement of these joints is necessarily small, as it is between vertebrae above where articulations are similar in kind.

articulations allow free

allows only slight

range of all

other

The

articulation of the pelvis with the femoral heads forms a rotary or

and socket joint which allows free movement in all directions. The depth of the socket, the acetabulum, is increased by circumferential fibrocartilage, the glenoid labrum, which also protects its rim. More than half the femoral head fits into the acetabulum, making it one of the strongest joints in the body and the most difficult to dislocate. ball

36

COMPONENTS OF HUMAN MOVEMENT Ligaments of the Pelvis Strong ligaments radiate in

directions over the articulations of the

all

These ligaments support the joints where, and as needed, during weight support and movement. In order to understand movement, one should have a general idea of the relation of the location of a ligament over a joint to the direction of the movement it limits. For example, if the pelvis is moved upward in front on the femora as in "pelvis tucking," or if the femora are moved backward on the pelvis — an extension of the joint in either case — the ligament which limits this movement lies on the front of pelvis.

the

joint.

This very important ligament, the iliofemoral or

the strongest in the entire body.

It

will

be discussed

Y

ligament,

is

in the study of the

femora and their movement. There are 19 ligaments (see Figure 6) which reinforce the three joints within the pelvis and the articulation of the sacrum with the coccyx. Not included among these is the inguinal or Poupart's ligament, which extends on either side of the front of the pelvis from a spinous process at the front of the crest of the ilium to a tubercle (slight prominence) on the more central part of the superior surface of the pubis. This ligament forms the lower border of the aponeurosis (tendon) of the external oblique abdominal muscle. Anyone who engages in strenuous activity should be aware of this ligament because it is the site of possible inguinal or femoral hernia. The articulations of the sacrum with the fifth lumbar vertebra are reinforced by a continuation downward of nine ligaments which join the mobile vertebrae of the spine above. In addition, four other ligaments connect the transverse processes of the fifth lumbar vertebra with the sacrum and ilium. Despite the strong ligamentous support at the lumbosacral joint, the fifth lumbar vertebra occasionally slides forward on the sacral table. Various factors can contribute to this difficulty, among them, very poor m\^.

\%

ANTERIOR LONGITUDINAL LIGAMENT

POUPART'S

/

^

Figure 6.

The

pelvis,

with ligaments.

---l^il

LIGAMENT

ILEOFEMORAL LIGAMENT

THE PELVIS

37

alignment of the spine on the pelvis with excessive continuous stress on the ligaments, especially the anterior longitudinal ligament. Another contributor may be- inherited weakness of the joint structure, which renders

unequal to the shocks of movement or a sudden fall. Seven ligaments reinforce the articulation of the sacrum with the coccyx and the bones of the coccyx with each other. As previously stated, many

it

life, earlier in the male than in the female. Four ligaments reinforce the pubic symphysis. Fourteen ligaments reinforce the articulation of the pelvis with the femora. Of these ligaments, the iliofemoral or Y ligament on the front of the joint (mentioned above) limits the backward movement of the thigh. The Y ligaments also play an important part in the alignment of the

of these joints fuse in later

They preserve the best balance of the spine by preventing the weight pressure of the upper body at the back of the pelvis central skeletal structure.

from decreasing its anteroposterior tilt. Should it do so, it would interfere with the continuity of the forward lumbar curve with the backward sacral curve. In standing, this ligament abolishes any steady

on the back

lumbar region.

in the

On

need

the other hand,

of muscle

when back

are overly tight and thus pull the pelvis up in back to increase posterior

tilt,

weight sags against the

Y

muscles

its

antero-

ligaments instead of centering in

the femoral joints. Ignoring the functional significance of the all

work

too often results in the use of exercises

Y

ligament

which have detrimental

effects

on body alignment and neuromuscular habits. One such harmful exercise is flexion of the trunk in the back-lying, legs extended position (see Chapter 23).

Because of the design of the skeletal structure, its upright position, and movement is mainly forward, the ligaments which experience the most harmful stress are the anterior sacroiliac, the iliolumbar, the anterior longitudinal, and the iliofemoral or Y ligaments of the femoral joints. Any persistent anteroposterior increase of the pelvic tilt will produce the fact that man's

pressure against these ligaments.

Muscles of the Pelvis

A detailed knowledge of all the muscles which help to control movement performing or teaching movewhatever the degree of one's knowledge may be, it should be accurate and functional. One need not dogmatically determine the patterning of muscle action which is essential for the success of a movement. An analysis of muscle action at any one moment of movement is never completely accurate, nor can it include all the muscles which act simultaneously as stabilizers of the body during the movement. In short, it is futile either to explain or to teach movement in terms of muscle action. in the pelvic area

ment. What

is

is

really not essential for

important

is

that,

COMPONENTS OF HUMAN MOVEMENT

38

Of the 57 muscles having their origin on the pelvis, 15 extend crosswise, upw^ard, and outw^ard from the front, back, and sides of the pelvis to attach to the spine and lower rib-case; 2 of these, the latissimus dorsi, attach the proximal end of each humerus to the back of the pelvis. Th^e latter two muscles play a major role in a person's ability to lift his body by his arms. In this situation, the amount of force applied at the back of the pelvis approximates that needed to counteract the weight of the body as it is lifted. The strong upward pull of the contracting latissimus dorsi muscles must be counteracted by the contraction of opposing muscles which will maintain the normal inclination of the pelvis. This is only one example of the many movements which require stabilization of the pelvis as the center of control of movement. Many more muscles, 42 in all, reach outward and downward to attach to the lower limbs. Of this number, 12 are two-joint muscles which influence the movement of both the femoral and the knee joints. They transfer the power of one-joint muscles of the pelvis to movement of the femora, the legs, and the feet in a mechanically advantageous way. The work of one-joint muscles cannot be substituted for them, or vice versa. The synergy of

movement

of the lower limbs requires the cooperative action of both

types of muscles. Without these two-joint muscles,

we would

not be able

to walk, run, or leap.

Four muscles lie in a position to complete the sides and base of the pelvic bowl. Two of them, the obturators internus and externus, are included among those which have their insertion on the thighs; the other two, associated through fascial tissues with the pelvic viscera, provide support from below.

The Psoas Major Muscles The psoas major muscles are unique because (1) they are centrally located in the body without being attached to the pelvis, (2) they function as postural muscles, and (3) they aid in flexion of the thighs. In the posture laboratory we attempt to coordinate the work of these muscles, especially as postural muscles, with that of all muscles which do attach to the pelvis. Insofar as this can be accomplished ideokinetically,

all

movement

of the

improved and performed with greater ease and safety. The claims made by some that they can "feel" the contraction of the psoas major mus-

body

cles

is

is

highly debatable, since these, like

The psoas major muscles

join the

all

muscles, are insentient (59).

lower spine to the proximal thighs,

crossing the front of the pelvis as they pass diagonally forward,

and outward from either side

downward,

low spine directly over the femoral joints to attach to the small trochanters on the inside of the femora. Only the Y ligament is interposed between them and the joint. The psoas major muscles attach above the pelvis to the sides of the twelfth thoracic and five lumbar vertebrae and their intervening discs, and on the front and of the

THE PELVIS

39

TRANSVERSALIS

MUSCLE I

PSOAS MAJOR M

QUADRATUS

LUMBORUM

PSOAS MINOR M ILIACUS

MUSCLE

Figure

7.

Front view of the pelvis, with right psoas major muscle.

lower borders of their lateral processes. Below the pelvis they attach by tendon to the small trochanter on the inside of the proximal part of each femur. Here their tendons have been joined by those of the iliacus muscles

which have

origin, in general,

on the inside of each ilium. The two muscles

are often referred to as one: the iliopsoas. It seems logical that the psoas major muscles, since they connect the low spine and the thigh and pass directly over the femoral joint, would be

almost continually active in maintaining the pelvis in a stable position in

marked anterowould be supported mainly by ligaments. Bas-

standing. Indeed, they are, unless the pelvis has such a posterior

tilt

that weight

majian has stated, "Almost everyone has lost sight of the principle that a muscle so close to a joint must have an important postural function"

M.

COMPONENTS OF HUMAN MOVEMENT

40

— both its parts — appears to be hip joint ..." (5, p. 209). muscle of the an active postural or stabilizing The other function of the psoas muscles is flexion of the femoral joints. When the trunk is flexed on the thighs, the origin of the psoas muscles is on the thighs; but when the thighs are flexed on the trunk, their origin is (5, p.

207).

He

also states that "Iliopsoas

on the lower spine.

No other pair of centrally anteroposterior

tilt

located muscles has so

much

influence on the

of the pelvis without actually being attached to

it.

This

may be demonstrated with a spinal column, pelvis, and femur with its head placed in the acetabulum. Shortening the distance between the small trochanter of the femur and the spine moves the pelvis up in front to decrease its tilt; lengthening the distance causes the front of the pelvis to drop downward and increase

its tilt.

There are several activities whose performance benefits immensely from efficient work of the psoas major muscles, working as postural muscles. One such activity is climbing mountains or steep hills (see Figure 5B). Another is walking upstream in a swift current that reaches the height of the upper thighs, but not the level of the thigh joints. In the former activity, the pelvis must be maintained under the trunk if the legs are to lift the body effectively; in the latter, if the pelvis is not maintained under the trunk, the wader (or fisherman) is likely to fall forward on his face.

Movements Movement among

of the Pelvis

the three bones forming the pelvis has been con-

and the pubic symphysis. The pelvis can rotate on both femoral heads, solely in the sagittal plane, only if its alignment is symmetrical. The movement increases or decreases sidered in the discussion of the sacroiliac joints

anteroposterior tilt. Symmetrical position of the pelvis is seldom found, however, and the plane of anteroposterior rotation tends to be at an angle with the sagittal plane.

its

Rotation to the right or left solely in the horizontal plane is possible if the rotation takes place on only one femoral head. When on both, however, the rotation occurs in a plane which is higher on the side of the pelvis which

moves backward. Likewise, possible

when

rotation of the pelvis solely in the coronal plane

on only one femoral head; but, when on both femoral heads, rotation occurs in a plane which is farther back on is

rotation takes place

the elevated side of the pelvis.

Movement of the pelvis in varying degree occurs with all movement of the lower limbs— sometimes to maintain the line of gravity through the supporting limb and very often to increase the range of movement of a limb, especially after

backward movement

is

stopped by the

Y

ligament at the

THE PELVIS

movement such movements as

thigh joint. This abihty of the pelvis to increase sports,

and particularly

in

dancing in

is

41

noticeable in

the arabesque.

Several skeletal studies (63, 80) indicate persistent symmetry in the position of the pelvis in standing,

which occurs through a combination

of

rotary deviations in planes approaching the position of the three cardinal planes.

The

resulting pattern of bodily alignment

is

discussed in Chapter 17.

The Spinal Column

The

spinal

column participates

in

some manner

in all

movements

of the

It also has many other mechanical functions — more

upper and lower limbs. than those of any other skeletal part. Nature has provided for maximal efficiency: no one function interferes v^ith another, because of the unique

The various parts, in their similarities and differences, meet special situations at different levels of the spine. column probably has more trouble adjusting to the upright

design of the spine.

are well designed to

The

spinal

any other skeletal part. When upright, the spine experiences severe than it did when horizontal. The damaging effects of these stresses increases with (1) persistently poor alignment of the spine for the weight it must support and transfer to lower levels; (2) awkward mechanics of movement, which often require the spine to perform work that the lower limbs should perform; (3) various conditioning, posture, and fitness exercises which lead to inefficient habits of neuromuscular position than stresses

much more

coordination; (4) long-continued bodily positions, as often required in one's

occupation; (5) heavy work; and (6) continued strenuous activity. In these stresses, the spine

is

forced to

move

or do

work which should be

all

per-

formed by other, more suitably designed joints. Only through understanding how the structure of the spine provides for its various mechanical functions can the student or teacher of motor performance have respect for, and treat with intelligence, each of these functions.

Mechanical Functions of the Spine Although the spinal column extends from the base of the head through the back of the pelvis, our present discussion deals only with that part above the sacral table of the pelvis. It is composed of 24 separate bones, or vertebrae—the design of each being similar to the others, yet differentiated to

meet

42

specific situations in the three regions of the spine.

These three

re-

THE SPINAL

COLUMN

43

composed of 7 vertebrae; the thoracic, in the area of the rib-case, composed of 12 vertebrae; and the lumbar, in the area of the waist, composed of 5 vertebrae. Occasionally, where there are structural anomalies, there may be one more or one less vertebra in either the lumbar or the cervical regions. The mechanical func^ ^ tions of the spinal column are the following. gions are: the cervical, in the area of the neck,

1

It

supports and transfers to lower levels and finally to the relatively

small sacral table at the back of the pelvis the weight of the head,

When the spine deviates from perform this function and, concomitantly, its freedom of movement are reduced (see pp. 27 and 28). It provides a protective canal for the passageway of the spinal cord and nerves (cauda equina), which continue downward from the lower end of the spinal cord proper at approximately the level of the rib-case, shoulder girdle,

and arms.

efficient alignment, its ability to

2

first

3

It

lumbar vertebra.

provides side openings from the protective canal at each vertebral

from the cord {efferent nerves) and those going into the cord {afferent nerves). These spinal nerves are grouped and named according to their level of exit from and entrance to the spinal cord (see Chapter 15): 8 cervical; 12 thoracic; 5 lumbar; and, within the pelvis, 5 sacral and 1 coccygeal. It provides 24 Class I bony levers for small-range movement in all directions. These levers permit varying degrees of movement in the different regions of the spine and at different levels within each of the regions. The cumulative movement of the various vertebrae from the base upward gives the distal spine a fairly large range of movement in relation to its sacral base on the pelvis. It provides buffers or cushions, the intervertebral discs, which both connect the vertebral bodies (except the first and second) and absorb level for the passage of nerves going out

4.

5.

shocks.

Of these five mechanical functions, the efficiency of the last four depends largely on how well the first one, that of weight support, is performed. If the spine deviates habitually from good alignment in the same direction and location, a person cannot expect to move the bony levers of the spine efficiently or to absorb shock without danger of straining or even injuring his ligaments and muscles.

Structure of the Spinal

The

Column

spine forms a column by the stacking of the bodies of

its

ver-

tebrae and their intervening discs, and a canal by the alignment of the

COMPONENTS OF HUMAN MOVEMENT

44

neural arches of the

vertebrae (see Figure

CERVICAL

8).

VERTEBRAE

The ahgnment and

rein-

is

many

forced by

the

of

parts

vertebrae

the

of

relationship

various

strong

ligaments which give

THORACIC VERTEBRAE

great column strength. Complete or

the

partial dislocation of a

seldom

vertebra

When

curs.

it

oc-

does,

it

usually results from a

forward movement of a vertebral body on its supporting

LUMBAR VERTEBRAE

surface,

example, the fifth lumbar on the sacral for

table

(spondylolisthe-

and

sis),

in this situa-

there

SACRAL,

tion

TABLE

structural

The

COCCYX Figure 8. Lateral view of the spinal

lands a person on his pelvis,

is

usually

weakness.

dislocation

may

be precipitated by the column. shock of a fall which or by poor mechanics in repeated lifting of

heavy weights. As a whole, the spinal column is shaped somewhat like a pyramid with its bulk at its base and a gradual decrease in size until it reaches its most distal part, the atlas. The column is bilaterally symmetrical at all levels and, in ideal alignment, is bisected by the median sagittal plane of the body. To support weight, the spine, like any other flexible column, must take the form of balancing curves (Chapter 16). Two of these curves, with their convexity forward, develop after birth to prevent the spine from buckling under the weight it must support as the trunk is placed upright. Thus, the spine curves forward in the cervical and lumbar regions while retaining its original

ment

backward curve

in the thoracic

and

The arrangebe more markedly

sacral regions.

of the vertebrae in the three regions appears to

curved on the front of the spine within the trunk than on the surface of the back at the tips of their posterior processes.

The

axis of the spine

tween the

first

cervical

is

and

an imaginary line of the shortest distance befifth

lumbar vertebra. Todd stated that

this

THE SPINAL axis should

be parallel with and close

fact that the center of gravity

is

COLUMN

to the line of gravity (84, p.44).

in front of the

45

The

upper part of the sacrum

gives credence to her statement.

The

spine's flexibility results

with each other

from the articulations of the vertebrae

at six different places (four places for

the atlas and axis),

and from the elasticity of the intervertebral discs. This flexibility, however, can be a source of trouble in that it allows the spine to deviate from good alignment for weight support, both laterally and anteroposteriorly. The shock of movement is cushioned by connecting fibrocartilage (see which extend from the axis, the second cervical vertebra, to the sacrum. The size and shape of these discs varies somewhat in the three regions of the spine, but each conforms with that of the vertebral bodies it connects. In the cervical and lumbar spine the discs are thicker in front than in back; this aids the formation of the two forward p. 12), the intervetehral discs,

curves. In the thoracic spine each disc

is

of uniform thickness, but the bodies

of the vertebrae themselves are thicker posteriorly, thus favoring the orig-

backward curve of this region. discs make up one-fourth of the length of the spine, excluding the atlas and axis. This length, however, is not equally distributed in the three regions of the spine. It is greatest in the cervical and lumbar spine, and this fact helps account for the greater mobility of these areas. These elastic discs adhere closely to the bodies of the vertebrae, allowing no movement between the disc and the body. The discs themselves stretch, however, and their elasticity enables them to return to their original form when stress, which may be of various types, is removed. Persistent deviation in the same inal

The

direction in the alignment of the upright spine, however, subjects the discs to continued

asymmetrical pressure and deformation from which they (as is normal) with each night of rest. In sitting, standing,

cannot recover

walking, running, and jumping, the reactionary force from the ground (see p.

21) can be absorbed in the vertebral bodies and discs

efficient alignment.

When

it is

when

the spine

is

in

and ligaments must take part extra work, in some cases, can

not, muscles

in the absorption of the reaction;

and

this

lead to undue muscular strain and pain.

Structure of a Vertebra

Each vertebra of the spinal column, except the first, is composed of a body as its front segment, and a neural or vertebral arch as its back segment. These two segments enclose the vertebral foramen. The body is the largest part of a vertebra. More or less cylindrical in shape, it supports the weight of structures above it when the trunk is upright. Its upper and lower surfaces are flattened and rough to give attach-

ment

to the connecting fibrocartilages or discs.

46

COMPONENTS OF HUMAN MOVEMENT

POSTERIOR

PROCESS

LATERAL

PROCESS SUPERIOR ARTICULAR FACET PEDICLE

BODY

SUPERIOR ARTICULAR FACET

ARTICULAR FACET

FOR RIB LATERAL

PROCESS ARTICULAR FACET

FOR RIB

NOTCH

ON PEDICLE

SPINOUS PROCESS-1 .

NFERIOR ARTICULAR

PROCESS

B. Figure 9.

A

typical vertebra

The neural arch

is

viewed (A) from above, and (B)

laterally.

made up of two pedicles and two laminae, and it The pedicles, the front of the arch, project backof upper, outer back of the vertebral body. The lam-

supports seven processes.

ward from

either side

inae complete the arch by fusing together at center back (see Figure 9).

Of the seven processes on the neural arch, one extends upward and one extends downward at the junction of the pedicle and the lamina on either

THE SPINAL

COLUMN

47

on adjacent vertebrae; one projects sideways from the same junction on either side to form lateral or transverse processes and one, the posterior or spinous process, extends backward from the junction of the laminae at center back. The articular surfaces of the two upper and two lower processes face in opposite directions: inward and outward, as in the lumbar vertebrae; forward and backward, as in the thoracic vertebrae; or obliquely upward and downward, as in the cervical vertebrae. The direction they face has an important bearing on movement in the different areas of the spine, on the transfer of weight toward the pelvis when the spine is not upright, and on the control of the spine from the pelvis. Notches in the upper and lower surfaces of the pedicles meet similar notches on adjacent vertebrae to form the intervertebral foramina through which the spinal nerves and blood vessels pass. side of the neural arch to articulate with like processes

Distinguishing Characteristics of Vertebrae

Vertebrae

may be

spine by one or

more

identified as belonging to

one of the regions of the

of the following distinguishing characteristics

Cervical Vertebrae (see Figure 1.

Short spinous process which are bifid

1 0)

(split into

two

lobes) at their

apices

FORAMEN INTRANSVERSE PROCESS

SUPERIOR ARTICULAR FACET

SPINOUS PROCESS

Figure 10. Cervical vertebra, upper surfaces.

COMPONENTS OF HUMAN MOVEMENT

48

borders of their bodies prolonged downward in front Articular facets on the neural arch for adjoining vertebral articula-

2. Inferior 3.

tion face obliquely

upward above and downward below

4. Six articular facets 5.

A foramen in the lateral processes and sympathetic nerves

for the passage of arteries, veins,

Thoracic Vertebrae (see Figure 11) 1.

Demi-facets above and below on either side of the posterior lateral aspects of the body which meet similar ones on adjacent bodies to form, with the intervening disc, a complete articular facet for the

2.

head of a rib A facet on the front of the

distal part of the transverse process

on

beyond

its

either side, for articulation with the tubercle of a rib just

downward-slanting neck 3. Articular facets for adjoining

vertebrae on either side of the neural

arch facing somewhat backward above and forward below 4 5. 6.

Slightly greater depth at the back than at the front Twelve articular surfaces A marked downwart slant of the spinous process

SUPERIOR ARTICULAR FACET

of the

body

DEMI-FACET FOR

HEAD OF RIB

BODY

NOTCH INFERIOR ARTICULAR

ON PEDICLE

DEMI-FACET FOR HEAD

OF RIB

PROCESS SPINOUS PROCESS

Figure

IL

Lateral view of a thoracic vertebra.

THE SPINAL

COLUMN

49

SPINOUS

PROCESS"

1

^ :^K

LAMINA

1

1^

-J SUPERIOR ARTICULAR

"/:

>v0^lE^^^RANSVERSE

SPINAlT

PEDICLE

FORAMEN-

BODY

Figure 12.

A lumbar

vertebra, viewed from above.

Lumbar Vertebrae

(see Figure 12)

1

Articular facets for adjoining vertebrae on the neural arch

2

inward above and outward below body Large spinous processes, approximately horizontal

on either

side facing

3.

A

relatively large

in position

4. Six articular surfaces

Characteristics of Atypfcal Vertebrae

The vertebrae which do not

exhibit the above characteristics for each

region are the atlas; the axis and the seventh cervical vertebra in the cer-

SPINOUS PROCESS

FORAMEN IN TRANSVERSE PROCESS

SPINAL

FORAMEN 2f

ARTICULAR

Figure 13.

ARTICULAR

SURFACE FOR

SURFACE FOR

OCX)NTOID

OCCIPITAL

PROCESS

CONDYLE

The

atlas,

viewed from above

COMPONENTS OF HUMAN MOVEMENT

50

OCCIPITAL

CONDYLE

POSTERIOR TUBERCLE POSTERiKDR ARCH FORAJMIEN IN ,

m

.

r/

x

^

TRANVERSE

PROCESS

ANTERK)R

^"'VJ^^ SUPERIOR ARTICULAR SURFACE FOR OCCIPITAL CONDYLE

ARCH Figure 14.

The base

which the head

vical spine;

of the skull, with the lower maxillary

bone removed, and the

atlas

on

and twelfth vertebrae

in

sits.

and the

first,

ninth, tenth, eleventh,

the thoracic region.

The

Ax\diS

and Axis

To perform

the

same mechanical functions as other vertebrae of the and axis had to be different from that of others.

spine, the design of the atlas

The foramen

of the atlas, through w^hich the central nervous system passes from the head into the spinal canal, had to be centered under the opening passage at the base of the head, the foramen magnum (see Figure 53). This

meant that support of the weight of the head and provision for movement on the atlas without damage to the nervous system had to be made on either side of the foramen. There could be no body as in other

positioning its

THE SPINAL

COLUMN

51

with enlarged masses on either side which are closer to the front than to the back of the ring, and with only a rudimentary spinous process which does not interfere with exvertebrae. Hence, the atlas

is

formed

like a ring,

tension of the head on the spine (see Figures 13 and 14).

The

masses of the atlas provide elongated cradle-like articular surfaces on their upper aspects, just inside the lateral processes. These surfaces receive the downward-projecting, rocker-like occipital condyles at the base of the head on either side of its foramen magnum. On the lower aspect of each lateral mass there is a rounded, approximately horizontal lateral

articular surface

which rests on the upper

articular surface of either pedicle

of the axis below.

The axis resembles other vertebrae except for its body, which is elongated upward (the odontoid process or "stolen body" of the atlas) to fit into a ring of bone and ligament formed by the front rim of the atlas and a strong transverse ligament (Figure 13). Thus, a pivot joint

the atlas with the head process

itself

it

is

formed which allows

The odontoid

supports to rotate horizontally.

supports no weight in the upright position (see Figure 15).

The seventh

cervical vertebra can be distinguished from others

long spinous process which, unlike other cervical vertebrae,

The

is

by

its

not bifid.

atypical thoracic vertebrae, except the twelfth, can always be dis-

tinguished from others in the

same region by the

location

and number

ODONTOID PROCESS SUPERIOR ARTICULAR

SURFACE

TRANSVERSE PROCESS

BODY

SPINOUS PROCESS

Figure 15. The axis viewed from above.

of

52

COMPONENTS OF HUMAN MOVEMENT

ONE DEMI-FACET

COMPLETE FACET

DEMI-FACET INFERIOR ARTICULAR FACET. FACING OUTWARD Figure 16. Peculiar thoracic vertebrae.

facets

and demi-facets

for articulation

with the heads of the

ribs.

These

tend to differ from person to person (see Figure 16).

The

is distinguished from all others by the on the neural arch. Those above face backward, as they do in other thoracic vertebrae; but those below face outward, as they do in the lumbar vertebrae.

facing of

twelfth thoracic vertebra its

articular facets

Ligaments of the Spinal Column

The vertebrae require many ligaments to connect and reinforce their complicated structure. Some ligaments are short since they connect adjacent vertebrae; other very long ligaments connect the entire length of the spine; while still others reinforce the articulation of the atlas with the axis, and the atlas with the head.

There are two types of articulation in the spinal column: the slightly movable joints between the bodies of the vertebrae and between the body of the fifth lumbar vertebra and the sacral table; and freely movable joints between the vertebral arches, between the ribs and the spine, between the atlas and the axis, and between the atlas and the head.

THE SPINAL

COLUMN

53

The Vertebral Bodies

The bodies

of .the vertebrae

and

their intervening discs are connected

through their entire length on the front by the anterior longitudinal ligament, which is broader below than above, and on the back by the posterior longitudinal ligament,

ments blend with

all

which

is

broader above than below. These two

other ligaments adjacent to

them

liga-

(see Figure 17).

ANTERIOR LONGITUDINAL LIGAMENT POSTERIOR LONGITUDINAL LIGAMENT SPINOUS

PROCESS LIAGMENTUM FLAVUM INTERSPINOUS LIGAMENT

SUPRASPINOUS LIGAMENT

SUPERIOR ARTICULAR PROCESS

TRANSVERSE PROCESS SPINOUS

A

LIGAMENTS '"] INTERVERTEBRAL

ikJSfA/lteiDISCS

PROCESS /

^

RIB

Figure 17 (A). Median sagittal section of two lumbar vertebrae with ligaments. (B) Right lateral view of vertebrae with ribs and ligaments making a design similar to truss work of a bridge.

COMPONENTS OF HUMAN MOVEMENT

54

The Neural Arches

The ribs are

freely

movable

and those of the Figure 18) differing somewhat in

articulations of the neural arches

each envdoped

in a capsule (see

thickness and lined in general with a synovial

The laminae flava,

which

is

membrane.

'

by the ligamentum which may aid muscles in after bending forward. These

of the neural arches are connected

made up

of yellow elastic tissue

returning the spine to an upright position

ligaments, however, can lose their elasticity

when

they are subjected to

excessive or long-continued pulling stress, as in a kyphosis (exaggerated

backward curve) of the thoracic spine. The supraspinous ligament connects the apices of the spinous processes continuously from the seventh cervical vertebra to the sacrum. The interspinous ligaments connect the spinous processes

still

further.

seventh cervical vertebra upward, the supraspinous ligament

is

From

the

replaced

by the ligamentum nuchae, which attaches above to the occipital protuberance and median nuchal line on the base of the skull back of the foramen magnum (see Figure 53). This ligament forms a septum between the muscles on either side of the back of the neck. It is the rudiment of an important elastic ligament which sustains the weight of the head in some four-legged animals. The transverse or lateral processes of the vertebrae are connected by rather indistinct intertransverse ligaments which are entirely lacking in the cervical region.

The

Atlas, Axis,

and Head

At least fifteen short ligaments reinforce the relationship of the atlas, and head. They provide the added strength which is needed to protect the spinal cord from the constant movement which occurs in this area. axis,

CAPSULE

NECK OF RIB

INTERVERTEBRAL FIBROCARTILAGE Figure 18. Rib with capsules, side view.

(DISC)

THE SPINAL

Movements

of the Spinal

COLUMN

55

Column

Since the spinal column must support great weight, resist shock, and protect the spinal cord,

movement between any two vertebrae must be

even though movement of the column as a whole is considerable. Motion is freest where the vertebral bodies are smallest or the discs are thickest — the former in the cervical, the latter in the lumbar spine. The direction of motion in any region is controlled by the shape and direction of the articular processes of the neural arches. Flexion is the freest of all moveslight

ments.

Movements

of the spinal

column include flexion (forward bending),

extension (backward bending), lateral flexion (bending to the side), rotation,

and circumduction. These

as within

differ in

degree

in the three regions as well

each region.

The Cervical Spine All

movements are permitted

the articular processes. Extension

in the cervical spine is

by the obliquity of

freer than elsewhere in the column.

is free, but less i'ree ttian m the lumbar spine because it is limited by the downward prolongation of the front of the vertebral bodies. Lateral flexion is more extensive than elsewhere, combining with rotation except inthe lower cervical region where it occurs by itself. At the atlantooccipital joint, flexion and extension of the head on the atlas are free. The very slight lateral bending which is allowed tends to be obliquely lateral. There is no rotation at this joint; the movement of turning the head to the side does not occur here. At the adantoaxial joints the horizontal rotation of the head and atlas, as a unit, takes place around the odontoid process. Rotation here is more extensive than in any other part of the spine. Slight flexion and extension

Flexion

are allowed as

is

limited lateral flexion.

The Thoracic Spine Extension is checked in the thoracic spine both by the meeting of the laminae and spinous processes and by the shape of the articular processes. Rotation, which flexion

is

is

limited

freest in the

by the

The movement

upper thoracic area,

is

permitted. Lateral

ribs.

of the ribs in the thoracic area

is provided for both by and costotransverse articulations with the vertebrae, and by their sternocostal and interchondral articulations at the front (see Figure 19). Their movement is very complicated because of the differing lengths of the ribs and the differing slant of their necks. It occurs mainly through a gliding rotation in the joints which raises the front of the ribcase slightly and widens and increases its depth from front to back, mainly at the level of the lower ribs but only slightly at the upper level.

their costovertebral

56

COMPONENTS OF HUMAN MOVEMENT

COSTOTRANSVERSE ARTICULATION

^^^^^^COSTOVERTEBRAL ARTICULATION

1st rib ARTICULATION.

PERMITS NO MOVEMENT

COSTOSTERNAL ARTICULATIONS

INTERCHONDRAL LIGAMENTS

Figure 19 (A). Articulation of ribs with body and transverse processes of a vertebra. (B) Sternocostal

and interchondral articulations on right

side, front view.

The Lumbar Spine Because of the thickness of the lumbar intervertebral discs, flexion in is very free, Extension is limited by the meeting of the spinous processes; therefore, it depends somewhat on the length of the individual's spinous processes. A small amount of rotation is allowed, and this tends to occur with lateral bending. Circumduction throughout the spine is a combination of all other movements; it increases in range as distance from the sacral table increases.

thejumbar^ine

THE SPINAL

Factors Interfering with Functions of the Spinal

There are thr^e

factors, evident in varying

COLUMN

57

Column

degree in the movement of

which interfere with the primary function of the _sj)inal column, weight support, and with its secondary function, moveme nt These are (1) movement in the spine which should be acc omplished logi cally by movement in other joints, especially the femoral (2 reduction in flexibility of the ribs b y repeatedly and forcibly lifting and holding them practically all individuals,

;

high, usually in response to a

and

(3) lack of free

mov ement

number

)

of false ideas about "good" posture;

of the shoulder girdle, usually resulting

from

tense muscles in this area and in the neck.

These three

factors interfere with the spine's (1) efficient alignment,

any large upper and lower extremities, (4) ability to tie together patterns of movement of the arms and legs, and (5) ability to focus reaction to all bodily movement in the bodies of the vertebrae and their intervertebral discs without undue muscular and ligamentous strain. All movements of the various parts of the body are interdependent and interrelated, and the degree of efficiency with which each movement is performed is in direct relation to the efficiency with which the spinal column performs i ts primary functio n, that of weight sugj^rt. When the spinal column contributes to range oi mo^vement, tor example, in lateral bending of the trunk, concentration on lateral bending of the central axis of thej^ trunk (rather than on movement at the surface of the body) invariably'lF results in a greater range and a more efficient distribution of the movement of the spinal column. This procedure has proven successful repeatedly (2) flexibility , (3) efficien t reaction to the centrifugal force of

movement

of the

in our posture laboratory.

The Femur and Femoral Joint

Hmb. It serves two mechanical body weight and movement. In contrast to the limited range of movement of the bony levers of the trunk, the femur has a rela-

The femur

is

the upper bone of the lower

functions: support of

tively great

by

its

ball

range of movement in

and socket

all

directions. This

is

the longest and strongest bone of the skeleton.

with the pelvis at the acetabulum. its

provided

Femur

vents interference from the pelvis by curving outward from that

is

joint.

Structural Design of the

The femur

movement

It

its

It

circum-

articulation

then descends diagonally inward so

knee is in line with its upper one femur ends in two large downward prothe condyles, the inner one being longer than the outer one so

inferior articular surface at the

at its head.

jections,

The

distal part of the

that their articular surfaces are horizontal for articulation with the approxi-

mately level superior surface of the tibia of the

The femur may be studied

leg.

in three parts (see Figure 20): the

upper or

proximal portion, the body or shaft, and the lower or distal portion.

The Proximal Femur

The proximal femur is composed of a head, a neck, and two bony enlargements: the great and small trochanters.

The head half

its

is

surface.

rounded, and It fits

its

articular surface extends over

more than

snugly into the acetabular cup on the pelvis where

position is further protected by the glenoidal labrum, which deepens the cup. This structural arrangement results in a joint (the iliofemoral or femoral joint) which has a unique resistance to dislocation. Indeed, the

its

head remains is

cut away.

The

in the

all

Hgamentous reinforcement

other joint has such a marked degree of security. neck of the femur is a flattened pyramid of bone extending diag-

onally outward

58

acetabulum even after

No

and

slightly

downward from

the femoral head to connect

THE FEMUR

AND FEMORAL

JOINT

59

with the proximal end of the shaft of the femur, thus giving the femur the form of a bent lever. The angle of the neck to the shaft varies with both age and sex: it increases with age and is greater among females.

it

The great trochanter is a

large bony mass at the upper part of the juncneck and the shaft. It is the most lateral part of the femur, even further from the central line of the body than the most lateral part of the pelvis. All too many people confuse the great trochanter with the femoral (thigh or hip) joint — a notion which greatly impairs their understanding of the mechanical functions of the thigh. The great trochanter affords attachment to many muscles and hence is subjected to strong pulling forces, varying with the amount of work the muscles engage in at various times. The small trochanter is a bony prominence at the lower, back part of the base of the femoral neck. A rough intertrochanteric or spiral line connects the two trochanters both on the front and back of the base of the neck. Only the psoas major muscle attaches to the small trochanter. The iliacus, as a part of the iliopsoas muscle, attaches just below the small trochanter on the femoral shaft. tion of the

NECK GREAT TROCHANTER

GREAT TROCHANTER

HEAD^< HEAD NECK INTERTRO-

INTERTROCHANTERIC

CHANTERIC SMALL'

LINE

^

^

LINE

TROCHANTER Ji

SMALL TROCHANTER

BODY OR SHAFT ADDUCTOR TUBERCLE

ADDUCTOR TUBERCLE

^

CONDYLE MEDIAL \/y ^^ CONDYLE ie^^N^S/^^\^V^^^N^VWV/^^^^^^^^^^^

Muscles at Work

The

functioning of the skeletal mechanisms for weight support and move-

ment discussed

in earlier chapters ultimately

An understanding

muscles.

of

what processes

depends on the work of body enable muscles

in the

accomplish their work should help a person determine the extent and degree of activity most favorable to his own well-being. Muscles require oxygen to perform their work, yet the body carries no to

The body's oxygen supply can be exhausted in 20 seconds of strenuous activity. To meet the oxygen demands of working muscles, nature has provided mechanisms which make oxygen appreciable reserve of this vital element.

and even in anticipation of activity before These mechanisms are the respiratory, circulatory, and nervous systems — interrelated and interdependent in their function of enabling available, often within seconds

it

begins.

muscles to play their part in movement (13-15, 52).

The Respiratory System

The

respiratory system

is

a very complex

mechanism containing many

branching tubes leading into the functional part of the lungs, the alveoli, where the interchange of gases takes place. The lungs have no muscle power of their own to increase or decrease their

volume

of air. Instead, the thorax acts as a

pump

to

produce the

in-

flow and outflow of air from which oxygen can be extracted (see Chapter

The

its origin in three tubes: two in the nose mouth. These passages connect first with the pharynx, then with the trachea, which divides into two main branches (the bronchi) to the right and left lungs. Each bronchus subdivides into as many as 20 tubes, which in turn subdivide into over a million very fine tubes ending in minute sacs, the alveoli, of which there are some 300 million in the entire lung area. The average alveolus expands and contracts more than 15,000 times a day (14). The alveolar surface area available for the ex-

11).

respiratory system has

and a third one

in the

129

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

130

change of gases is very extensive — about 40 times the surface area of the entire body. Thus, the oxygen in the air and the carbon dioxide in the blood can be exchanged very quickly in large amounts.

Lung Capacity

When (1 liter

the lungs are fully expanded, they can hold 6 to 7 liters of air

=1.06

quarts). At the

end of normal expiration they

known

two or more amount can be reduced by forced expiration liters of air,

still

contain

as the functional residual capacity. This to

one

liter of air,

the residual

volume.

The normal

adult at rest breathes 10 to 14 times a minute, inhaling

and

per breath (15). Thus the total air exchange, ventilation in the lungs, approximates 5 to 7 liters per minute. The total exhaling about 0.5

liter of air

amount of oxygen taken in from this amount of air is only about 0.3 liter. The maximum human capacity for breathing, pulmonary capacity, is about 30 times the resting ventilation. However, the respiratory rate is not the primary factor which limits man's physical activity; that role belongs to oxygen intake. Oxygen intake is a function of the circulatory system, which takes up and transports the oxygen to the tissues of the body. Maximal oxygen intake, to meet the demands of increased physical activity, is therefore a fair index of circulatory capacity but not of pulmonary capacity (13). Only a fraction of the inhaled air reaches the alveoli. In contrast to the one-way flow of blood in the circulatory system, there is a two-way flow of air in the tubes of the lungs. Only 0.5 liter of air, that amount which reaches the alveoli, is used in respiration. The rest of the inhaled volume remains in the tube system and is expelled on exhalation. This single system of tubes for both inspiration and expiration appears at first to be disadvantageous; on the other hand, an extra set of tubes would require more space and perhaps reduce the space occupied by the important functional alveoli.

The

great

number some

various reasons

of alveoli in the lungs alveoli

is

a safety provision.

become nonfunctional,

If

for

local restriction of

the final passages to these affected alveoli diverts their share of air and

blood to functional alveoli, ensuring an adequate gas exchange there.

Measurements of Lung Function The earhest measurements of lung function determined only the total lung capacity (on full inhalation, the residual volume of air in lungs after full exhalation), vital capacity (the amount of exhaled air after full inhalaand the distribution of air in the tracheo-bronchial tree. Since 1950, techniques have enabled man to measure various aspects of lung function (15), so that he can locate any specific lung problem which may tion),

new

occur.

MUSCLES AT

WORK

131

Regulation of Respiration

Although man can control respiration for a short time, he cannot deterhis normal breathing rate, or, in fact, whether he will breathe at all. Automatic control centers regulate the work of both the lungs and the heart to meet the need for oxygen as it varies, for example, with changes in the altitude, the quality of air, or the amount of exercise. These "decision centers" work for the preservation of life and therefore must be beyond man's control. The first regulatory center, a group of interconnected nerve cells which is accorded the major role in the control of respiration, was discovered in the lower brain stem in 1811. Since then many other chemically sensitive centers concerned with the regulation of breathing and circulation have been found in various parts of the brain, including the cerebral cortex. In addition to these centers there are receptors in the circulatory system which are sensitive to both chemical and mechanical stimuli and which can initiate reflexes to slow or even stop breathing. Other factors regulating respiration are the degree of inflation or deflation of the lungs, the state of wakefulness of the individual, the concentration of hormones in the blood stream, and some of the special receptors (spindles) in the muscles. Although our knowledge of the location and work of these centers has

mine

greatly increased,

many

puzzling questions concerning respiration remain.

As stated by Chapman and Mitchell, "Whatever its exact modus operandi, the respiratory control mechanism ordinarily prevents carbon dioxide from accumulating in any significant degree and virtually assures an adequate supply of oxygen over a range extending from rest to maximal exertion (13). The Quality of Air

The

air

we

breathe can be unsatisfactory for the alveoli in various re-

spects such as temperature, bial agents (10).

It

amount

of moisture, solid particles,

and micro-

must, therefore, be filtered and "conditioned" before

reaches the alveoli. The upper respiratory tract provides the main components of an "air conditioner." Within limits it can change the temperit

and chemical composition of inhaled air and can cleanse and germs. The mucous membranes of the nose, mouth, and pharynx, because of their extensive blood supply, have the unique ability to either warm or cool incoming air so it approximates body temperature. The hairs of the nose and the contours of its turbinate bones stop the passage of large particles in the air, while smaller particles are stopped by the hairlike cilia in the tubes of the lungs. These cilia operate synchronously and continuously in wavelike motion within a protective sheath of mucus to propel ature, humidity,

it

of foreign bodies

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

132

upward and outward with the mucus times explosively with a cough or sneeze. The removal

foreign particles

and carcinogenic substances depends on which are disposed of by ciliary action. this elaborate

Despite

their

for disposal

— some-

of bacteria, viruses,

attachment

system for cleaning inhaled

air,

to the particles

some

way

are not retrieved. These particles are attacked on their

particles

to or at the

by the lymphocytes of the blood stream. Some foreign particles may pass into the lymphatic system, to be lodged finally in lymphatic nodes; others may remain permanently in the lungs without harm. Still others, however, may finally cause serious pulmonary disease. alveoli

Various reflex responses to stimuli provide protection against the passage of water, harmful gases, or solid material into the bronchial tubes. of these reflexes

of breathing during swallowing.

person

is

momentary

the closing of the epiglottis and

is

unconscious,

it is

Because

this reflex

extremely dangerous to try

does not work to

make

One

inhibition if

a

the uncon-

scious person swallow liquid or medicine. In addition to the obvious cough-

and sneezing reflexes, man uses the less evident reflex of bronchial which helps him to combat irritating gases such as aerosols, smoke, and sundry harmful vapors. Repeated and severe constriction of the

ing

restriction,

bronchi reduces ciliary activity, obstructs the finer air passages, produces excessive

mucous

secretion,

and may

finally lead to cell

and possibly

to

lung damage.

The Circulatory System After air has reached the alveoli of the lungs, the next major link in the

chain of mechanisms which responds to exercise This system

is

is

the circulatory system.

responsible not only for the exchange of gases in the lungs

but also for carrying oxygen and nutrients to billions of including those of the muscles.

cells of

the body,

The Circulatory Pumps There are two circulatory pumps, the right and left ventricles of the heart, which force surging gushes of blood into arteries, the muscular tubes which lead away from the heart. (All vessels which empty into the heart are veins).

The

right ventricle sends blood to the lungs; the left, to all other

tissues of the body.

The entrance chambers where the heart receives blood The left auricle receives blood from

are the right and left auricles, or atria.

the lungs only, while the right auricle takes

it

from

all

other parts of the

body.

The Two Arms of the Circulation

The

and from body cells is known as the systemic and from the lungs, as the pulmonary circulation.

circulatory system to

circulation; that to

MUSCLES AT

The systemic arm,

carrying "red" blood, leaves the

WORK

133

left ventricle richly

supplied with oxygen and nutrients, including a mixed cargo of amino acids for tissue repair, glycogen (sugar) for energy, vitamins,

and hormones.

This blood passes through large arteries, into their subdivisions (the arterioles),

and

finally into the capillaries

surrounding the body

cells.

Here

an exchange of oxygen and nutrients for carbon dioxide, excess w^ater, heat, and the debris of protein metabolism, w^hich changes "red" blood into "blue" blood. Gas exchange is made possible by the red pigment myoglobin^ in the muscle cells, which has an even greater affinity for oxythere

is

gen than does hemoglobin.

The blood may

give to the body tissues from 15 to 18 percent of

oxygen during exercise, as opposed to only 12 percent increased surrender of oxygen in exercise as (1)

when

at rest.

its

The

caused by such various factors the depletion of oxygen and the accumulation of carbon dioxide and is

acid metabolic products in the muscle fibers, lease from the hemoglobin,

muscle

and

which stimulate oxygen

re-

(2) increased temperature in the active

cells.

After blood has passed through the capillaries of the systemic the circulation,

it is

collected in venules, then veins,

and

arm

of

finally in the in-

and superior vena cava, to be emptied into the right auricle, the beginning of the pulmonary circulation. On its way back to the heart (before

ferior

collected in the inferior vena cava), the blood absorbs from various abdominal organs, including the liver, nutrients needed by the body tis-

it is

sues (91).

The pulmonary arm

of the circulation receives the venous blood, heavily

laden with carbon dioxide and nutrients, in the right auricle.

From here

emptied into the right ventricle, which pumps it through the pulmonary and its subdivisions to the lungs to circulate it through the capillary bed surrounding the alveoli of the lungs. After the exchange of carbon dioxide for oxygen, the blood is collected in venules, veins, and finally the pulmonary veins, to be emptied into the left auricle. In the pulmonary circulation the right ventricle, as a fluid pump, and the thorax, as a gas pump, must synchronize their action according to the needs of muscle cells. Simultaneously, the blood flow of the systemic circulation, which is much more extensive, must keep pace with the blood flow of the pulmonary circulation. To do so, the left ventricle requires a pumping pressure ten times that of the right ventricle. As indicated earlier, the entire procedure of the respiratory and circulatory systems is under the control of various complex regulatory mechanisms or "command centers" in the it is

artery

'Myoglobin may have other roles too (13). when muscles intermittently contract and alternated with short periods of rest are

by long periods of

rest.

It

may

relax,

account for the smoothness of muscle work

and

work work followed

for the fact that short periods of

more productive than long periods

of

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

134

nervous system and in the major arteries (1). These mechanisms ensure the flow of enough air and blood to meet the overall needs of the body and its

particular parts according to their activities.

The Capillaries Capillary beds occur in both arms of the circulatory system. In the sys-

temic system they surround

all cells

they surround the alveoli.

The

1/1000 millimeter

of the body; in the

capillaries are

pulmonary system

very thin-walled (about

and they are so small that the blood

thick),

cells

must

squeeze through them in single file. If the capillaries of the entire circulatory system were laid end to end, their total length would be hundreds of miles and their total surface area would be enormous.

work

of capillaries greatly

outnumbers

all

The

entire fine net-

other vessels through which the

blood flows.

When

the body

each red blood cell remains in a pulmonary but when the body engages in vigorous activity, this time can be reduced to }i second without impairing the exchange of carbon dioxide and oxygen. The efficiency of exchange of gases in the lungs results in part from the large area of diffusion provided by the combined surface area of the alveoli and the extremely short path of diffusion through the very thin walls of is

at rest,

capillary in the lungs about

the alveoh.

% second,

More important, though,

is

the great ability of the red blood

pigment, hemoglobin, to combine with oxygen. The ability of

this

remark-

able substance to combine with, transport, and deliver oxygen to muscle

atoms. In terms of comparative ability, hemoglobin can bind 65 times the amount of oxygen that can be absorbed by the blood plasma. cells resides in its iron

The red liter.

A

cells in

the blood stream

decrease in their

number

number

4.5 to 5.0 million per milli-

or an increase or decrease in the varying

types of white cells poses a medical problem.

count

may be

An

increase in white cell

a warning of infection in the body, while any

marked

de-

crease in red cell count (anemia) can be the cause of an undue, unaccus-

tomed, and continuing fatigue. Rate of Heart Beat

The

pulse rate at rest, approximately 70 times a minute, varies in differ-

ent people but

lower in the person conditioned to strenuous activity. At peak demands for oxygen by active muscles (about 50 times their need when resting), the heart can increase its output to five times its output at rest by speeding up its rate of beating and by increasing the volume of blood propelled by each of its beats. The pulse may double or even triple is

its

rate of beating.

on

its

Much

of the heart response to increased

conditioning through exercise.

increases

its

Under

output mainly by speeding up

work depends

the stress of emotions the heart its

beating rate, but

its

output

MUSCLES AT is less

than

it is

under physical

per beat are increased.

by the

The

stress,

when both

move blood to supply oxygen. To

capacity of the lungs to

The mechanisms

is

determined

is

the body tissues, not by the assure a sufficient supply of

oxygenated blood to muscles engaged in strenuous usual supply of blood to the internal organs

135

the heart rate and volume

limit of one's physical exertion

ability of the heart to

WORK

activity,

some

of the

diverted to them.

that adapt heart action to muscle needs in exercise

One such mechanism is contained in the heart muscle itself, enabling it to adapt to differing demands. The autonomic nervous system also plays a role in adaptation. Changes of pressure at various places in the major arteries, especially the aorta, are transmitted to the central nervous system, then to the autonomic nervous system, whose sympathetic portion increases heart action while its parasympathetic portion depresses its activity. Hormones which reach the heart by way of the blood stream also have an influence on its function. are not yet fully understood.

Phenomena

of

Muscle Function

Muscle Tone

A very useful phenomenon Tonus

is

of muscle function

is

muscle tone, or tonus.

defined as the residual tension of a muscle

defined as the condition in which

and no measurable work

is

all

when

at rest; rest

is

interacting forces are at equilibrium

performed. Muscle tone

is

a neurally induced,

persistent condition, in contrast to the condition of the denervated muscle,

and

it

varies greatly from person to person.

residual tension

is

The

individual variability in

mostly a function of the amount of contraction and work

a muscle has been subjected to. On one extreme, overworked and overdeveloped muscles produce hypertonicity, a condition best described as "muscle-boundness." On the other extreme, underdeveloped muscles exhibit hypotonicity, or "flabbiness." Both extremes inhibit smooth and efficient muscle work in movement. Tonus in a muscle is comparable to the idling of an engine. A well-tuned engine idles smoothly and responds swiftly when called upon to work. The engine that idles too fast is inherently wasteful, and the engine that idles poorly often sputters and stalls. Good tonus, like the smoothly idling muscle engine, enhances the smooth initiation and performance of muscle work whenever it is needed. The "ignition" is never turned off. Where muscles must perform repetitive and prolonged holding work (as do the back muscles and muscles of the diaphragm), they often can do so more efficiently by muscle tone than by muscle contraction. Muscle tone performs holding operations with a minimal expenditure of energy and apparently plays the role of a buffer; that is, it acts like an elastic cushion against the shock of sudden fluctuations. The theory that tonus represents a state of contraction brought about

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

136

by random

motor units

activity of

in a resting

muscle has thus

contradicted by electromyographic studies (5, 50).

random phenomenon.

far

been

in fact difficult

It is

can possibly be explained as the product of a variable contractile activity of the muscle spindles (31, p. 184), whose activity in this respect may be compared to that of a servomech-

to think of tonus as a

It

anism, an automatic correcting device for the control of large amounts of power by means of very small amounts of power, an error-sensing feedback.

Oxygen Debt In contrast to other types of cells in the body, the muscle cells are unique

temporary deprivation of oxygen. This ability is a which enables muscles to meet emergency situations. When activity is increased in intensity or duration to the extent that more oxygen is needed than is available, energy is liberated by anaerobic ("without oxygen") chemical processes in the muscles, and an oxygen debt is accumuin their tolerance for

safety factor

lated.

The waste products

of anaerobic processes, chiefly lactic acid, are

tolerated only to a certain degree before muscles can no longer contract

and a

state of exhaustion

is

reached. After an oxygen debt has been in-

is needed, during which time oxygen consumption will occur at an increased rate until the oxygen debt has been paid and a normal chemical balance of the muscles has been reestablished. The time needed for this recovery depends on the magnitude of the oxygen debt and the physical condition of the subject. The heart and the brain, however, cannot tolerate an oxygen debt. They depend entirely on oxidative energy, and their function suffers immediately when their supply of oxygen falls. Exercise does not affect the oxygen supply of the brain as it does in the heart, where there may be a tremendous increase in the need for oxygen during exercise. This oxygen must be supplied by the coronary circulation. The ability to meet this need of the heart for oxygen is one of the most important factors hmiting the intensity and

curred, a period of mild activity or rest

duration of activity.

The Overload Principle

The technique

for strengthening

gressively increasing

muscles

is

to subject

work loads — the overload

load at any time must exceed in intensity or duration the activity. In addition to

efficiency in the heart

them

principle (37).

to a pro-

An

demands

strengthening muscles, overload produces

when

it is

called

on

to

over-

of prior

more

perform beyond earlier

re-

quirements. Likewise, breathing becomes more efficient with activity which taxes

it

to a greater extent.

The increased

strength in muscles brought about by overload

activity

becomes aware

of this

is

unfor-

The person in a physically demanding whenever he stops his work for a period of

tunately a reversible condition.

MUSCLES AT

WORK

137

must then go through a phase of "overload" reconditioning regain the muscle power his strenuous activity demands.

time, for he to

Breathlessness Breathlessness indicates a degree of oxygen debt which muscles have incurred through strenuous activity.

The time necessary

for a return to a

normal breathing rate is a function of the magnitude of the oxygen debt. The speed of payment is influenced by the individual's manner of breathing, which may be habitually too shallow even when at rest. This habit involves insufficient use of the diaphragm most of the time, especially in a state of breathlessness. It is logical that poor muscular habits of breathing will increase the degree and period of breathlessness brought about by strenuous activity. It is

never advisable to hold the breath during any movement requiring

great power, as in lifting a weight, even though this seems to be a natural

phenomenon during

"exercises of effort." Holding the breath closes the and increases intrathoracic pressure, compresses the large veins of the thorax, and interferes with the return of blood to the heart. Whether one inhales or exhales during a strong movement is of little importance so epiglottis

long as the epiglottis

is

not closed (78).

Second Wind Second wind represents an adjustment in respiratory-circulatory prowhich enables a person to continue strenuous or prolonged physical activity with renewed vigor and greater comfort. Preceding the onset of second wind a person sometimes experiences great physical distress, as evidenced by rapid, shallow breathing, an abnormal pulse, and other symptoms of physical distress, all of which vary in different individuals. Second wind may occur with dramatic suddenness, or it may occur so subtly that cesses

it

goes unnoticed.

We

still

cannot really explain second wind. Since one's physical limiis determined by the circulatory rather than the respira-

tation in activity

wind could be primarily a circulatory adjustment in the midst of strenuous or prolonged activity to meet the oxygen needs of muscles. It is also possible that to produce second wind the cerebrum, in concentrating on the goal of movement, has facilitated a more efficient neurotory system, second

muscular coordination. Although explanations are inadequate, second wind can be described as a subcortical reflex response to the needs of working muscles and to concentration on the attainment of a specific goal. Fatigue

and Exhaustion

Many

mental, emotional, and physical factors enter into the onset of need to put forth increased effort to

fatigue. Early signs of fatigue are the

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

138

maintain activity and the loss of precision of movement. Fatigue on by the accumulation of lactic acid, which decreases muscle

and lessens

its

power

not heeded, there

is

of contractility.

When

is

brought

irritability

these early signs of fatigue are

further accumulation of lactic acid, which

may

prolong

the time needed for recovery of chemical balance in the muscles to a period of several hours.

Although fatigue may occur at many sites in the neuromuscular system, what is felt as muscle fatigue is probably not located in the contractile fibers of muscles but in the synaptic connections at two places: first, at the junction of motor end plates with muscle fibers, and then between the neurons of the central nervous system. Nerve fiber itself is relatively indefatigable. Other sites of possible fatigue are nerve cell bodies and sensory end organs — but the first location of fatigue is probably at the motor end plates (52, p.

239).

The onset of general fatigue may not be noticed at first. It is usually marked by poorer performance (although one may think one is doing as well). The sense of timing becomes unreliable and errors are more likely perform the fine details of a series of muscular patterns has been impaired. Ignoring general fatigue can result in injury, the consequences of which far outweigh any value gained by working to

to occur, for the ability to

the point of exhaustion.

Fatigue becomes chronic

when

it is

not eliminated by a good night of

can result in poor appetite, loss of weight, irritability, emotional imbalance, lowered blood pressure with increased pulse rate, muscle sleep.

It

tremor, pallor, and other abnormal conditions.

When

a person experiences

few or most of these symptoms, he should put health and safety ahead whatever may have brought him to this state. Another situation which should not be ignored is the feeling of persistent fatigue which is unwarranted by the activity performed. A low red cell count in the blood stream or a high count of white cells may be responsible for this overtiredness. Whatever the cause, medical advice should be sought. a

of

The

Warm -Up

The warm-up

consists of a series of exercises

immediately preceding

strenuous activity which are intended to increase muscle

warmth and

sup-

pleness.

There up, yet

unequivocal evidence in support of the value of the warmwidely accepted as an essential preliminary to strenuous exer-

is little

it is

improves performance and helps to prevent injury. As reported by Grodjinovsky and Nagel (34, p. 117), some studies indicate that the warm-up has no beneficial effect on performance and may even hinder it; others show that it is neither beneficial nor harmful. Experience in the posture laboratory, however, indicates that the majority of students who cise that

MUSCLES AT

WORK

139

experience injury in strenuous activity have not w^armed up sufficiently before attempting strenuous work.

The warm-up, (1)

if it is

to

be of real value, should result in the following:

increased blood flow in the capillary bed surrounding muscle fibers

and hence an increased oxygen supply, which

will shorten the

time of ad-

justment of cardiovascular and respiratory systems to the stress of vigorous

warmth

of muscles, which will favor swift contracand quick relaxation of muscle fibers; and (3) reduced viscosity of muscles through their increased warmth, which will favor suppleness and hence delay the action of the stretch reflex (discussed below) in muscles antagonistic to movement. Slow movements which require strong muscular control do not seem to help a person warm up; movements of a faster type are more beneficial. The warm-up, whether for the athlete or the dancer, should not include activities which might injure cold muscles, such as forceful stretching of muscles, exaggerated range of movement, or sudden and forceful move-

exercise; (2) increased

tion with less use of energy

ment. Forceful Stretching of Muscles Forceful stretching of muscles activities,

is

practiced consistently in a variety of

including sports and dancing, in the belief that

it

lengthens mus-

and increases flexibility of joints. To carry on this practice without danger of injury (which might produce inflexible scar tissue), the individual should be aware of what goes on physically as he does it. Muscle fibers, fascia, muscle tendons, ligaments, nerves, and blood vessels are all placed under tensile stress in the forceful stretching of muscles

cles. All

these tissues are elastic within limits.

When

subjected to stress,

they change in form, but they return to their original shape

when

stress

removed, provided the amount and duration of stress have been within the limits of their elasticity. However, as Steindler put it, "Continuous passive tension produces permanent structural changes in the muscle in the form of interstitial fibrosis, and this occurs long before the breaking point is reached" (76, p. 46). Muscle fiber can be stretched to 1 .6 times its original length before it tears. Contracting muscle continues to be elastic, so it can be stretched even as it is contracting. This ability is evident in resistive exercises, in which one resists his own movement, or in the controlled lengthening of muscle against the force of gravity, as happens in the quadriceps extensor muscle in deep knee bending. is

Fascia, the "binding-together" support throughout the body, has conit will not remain permanently elongated or relaxed. If stress is momentary and moderate, fascia is not damaged and returns to its normal length, but when stress is continuous over a period of time, permanent elongation and relaxation

siderable elasticity. Subjected to limited tensile stress,

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

140

result.

Because the

or protracted pull,

elasticity of fascia varies in individuals, a

even within the usual

limits of safety,

momentary

can sometimes

result in fascial rupture or loss of elasticity.

Muscle tendon has

elastic properties similar to those of fascia. Its

to resist stretching to the point of

muscle, and therefore

it

is

being torn

is

more than equal

power

much

greater than that of

to the

pulHng force which

shortening muscle applies to it. An undue amount of stress, however, can result in tearing at the junction of tendon either with its muscle or with

bone. As early as the third decade of

life,

tendons

generative changes, especially in blood supply.

The

may be

Achilles tendon some-

times ruptures "spontaneously," apparently without cause.

tendon

at the

usually results

subject to de-

The

patellar

knee is sometimes a source of pain. Pain in any tendon from a pulhng stress —either too intense, or too frequent,

or both.

Ligaments vary in their cellular composition. Those which are most exposed to tensile stress, — for example, the ligamenta flava of the spine — are composed largely of elastic fibers. Even so, they can lose their elasticity under continuous tensile stress, as in the habitually rounded back, and become unable to return to their normal length. Nonelastic ligaments, when subjected to continuous stretching, can be permanently lengthened and thus rendered inefficient in their protection of joint relationships. Examples of this damage are found in the deltoid ligament of the habitually pronated foot, in the internal collateral ligament of the knee when weight thrust occurs constantly to the inner side of the joint, and in both internal and external collateral ligaments when the knee is subjected to too great a degree of rotation. Nerve fibers and blood vessels are among the softer tissues which are subjected to tensile stress when muscles are forcibly stretched. They are subject to damage along with surrounding connective tissues when pulling stress is too great. For this reason, tissues may bleed if muscles are stretched too forcefully.

The Stretch Reflex Another phenomenon of functioning muscles is the stretch reflex, which activates an automatic contraction of muscle fibers when they are subjected to tensile stress. The existence of this reflex leads one to question whether forceful stretching results in longer muscle fibers or increased muscle suppleness. Perhaps it explains why in some activities, such as the dance, there can be no let-up in the practice of muscle stretching; otherwise, the elasticity of soft tissues within and surrounding muscles constantly tends to return these tissues to their original length. It should be noted that the stretch reflex exists only in the contractile fibers of muscles; operate in any passive tissues.

it

does not

MUSCLES AT

WORK

141

Muscle Soreness and Pain Transitory pain in muscles following exercise is probably caused by an accumulation of lactic acid in muscle tissues, and it subsides as the lactic acid is removed. A similar pain, ischemic pain, is caused by insufficient

blood supply to the muscle and

is

often accompanied by

numbness

or muscle

cramp.

The pain and soreness that occur the day after exercise can probably be attributed to small tears in muscle tissues. This tearing most frequently occurs in muscles undergoing lengthening contraction when increased tensile stress is placed on active fibers. It can occur also in forceful stretching of muscles that is sudden or beyond the limits of elasticity. Such tears are often accompanied by swelling, with resulting pressure on pain nerve endings (78,

The

p. 154).

author's analysis of muscular pain patterns encountered in the

posture laboratory indicates that pain tends to occur in those muscles which are

more frequently used

and that the patterns skeletal alignment.

in

The

side.

This condition

from

may be

may be accompanied by

precipitated suddenly by a it

low on one may be

fairly constant, especially in the

in the area of the thoracic spine, generally

period of time. With rest,

efficient

characteristics of these pain patterns are multi-

faceted and complex. Pain

back and sometimes

maintaining equilibrium in skeletal alignment,

as a rule are related to deviations

movement, or

finally vanishes,

it

suboccipital pain.

may be

but

it

It

continuous over a

comes again, often much

worse.

When no medical problem is involved, work in the posture laboratory can promote increased efficiency in the basic neuromuscular habit patterns revealed in skeletal alignment to bring the pain problem under control it entirely (Chapters 18-23). Needless to say, the more neuromuscular habits and the longer the individual has experienced pain, the longer the time needed to eliminate the pain. Any procedure which relaxes muscles and increases their blood supply hastens recovery from pain and soreness. Light exercise promotes a better supply of blood to the muscles than complete rest and should be pursued unless severity of injury to muscles or joints precludes further activity. Massage, always toward the heart, may be substituted for or added to light exercise. A hot bath or the application of heat pads is usually a readily available and beneficial therapy, although this may be contraindicated at first in case of a joint sprain with swelling of surrounding tissues. In that case cold applications are needed to reduce swelling, and heat may be apphed later to aid in the disposal of waste products in the tissues. Experience in the posture laboratory has shown that the most successful means of reducing soreness and pain in muscles is the daily practice of the constructive rest position (see Chapter 19).

or to eliminate rigid the

142

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

Muscle Development and Overdevelopment depends on five factors freedom from fatigue, (3) store of readily available nutrients, (4) temperature, and (5) ability to recover from work. Each of these factors is influenced by the training to which muscles have been subjected (78). Muscle development is associated with size, strength, and endurance of the muscles. Their increase in size results from larger (rather than more) contractile fibers, an increase in the amount of sarcoplasm, and an increase in connective tissue which harnesses muscle fibers together. As connective tissue is subjected to functional stress— whether in muscle, tendon, or ligament — both its cells and the amount of ground substance surrounding these cells increase in number. Increase in the strength of a muscle cannot be judged by the increase in its size; strength must be measured by increase in pulling force— that is, power of contraction — which is a function of the contractile fibers only

The

(1)

quality of the physical condition of a muscle

tone or degree of firmness,

(2)

(78, p. 178).

Endurance in a muscle means its ability to delay the onset of fatigue by balancing catabolic and anabolic processes as it works. Efficiency of the respiratory and circulatory systems greatly assists the muscle's ability to endure work. Another factor which increases effectiveness of trained muscles is better neuromuscular coordination, an increased skill in movement with elimination of unneeded muscle work. This coordination may be obtained through persistent training and practice, yet the ultimate in motor skill is perhaps unattainable except through improvement in skeletal alignment. Persistent physical training rarely results in change in habitual skeletal alignment; such change is best attained through the use of ideokinetic techniques to improve efficiency of the basic neuromuscular habits, which influence the performance of all movement. Overdevelopment of muscle produces bulky contractile fibers, increased connective tissue with toughening (as in a "tough steak"), increase and thickening of sarcoplasm, and increased viscosity of muscle. All these changes result in decreased elasticity and suppleness of the muscle, which in turn inhibits range of movement. Limited movement is not the only handicap which results from muscle

overdevelopment. Lack of muscle suppleness all too often predisposes muscle tissues and joints to injury when the muscle is subjected to a puUing force too strong for it to withstand. The pulling force may be applied purposely (as in forceful muscle stretching), or it may occur accidentally (as in strenuous exercise), or, for that matter, it may just result from everyday activities.

MUSCLES AT

WORK

143

Overdeveloped muscles are still cultivated by persons engaged in strenuous activities, whether competitive sports or the dance, because much teaching wrpngly emphasizes the mechanics of the isolated movement instead of the mechanics of the complete skeletal machine. It is unfortunate that so

much

activity teaching fails

to

stress

the internal

mechanics of the human machine, because complete body efficiency is both the prerequisite to all smooth functioning of muscles and the most effective barrier against injury.

14 Principles of

Muscle Function

An

understanding of the principles of muscle function

is

gaining a clear concept of a specific pattern of movement.

prerequisite to

A

sound knowl-

edge of the principles of muscle function, furthermore, favors a more intelligent practice of movement patterns, thus speeding up the learning process and reducing the chance of injury. When muscle contracts, it exerts an equal pull on each bone or other tissue to which it is attached. To produce movement of one attachment and not the other, therefore, the stationary end must be stabilized by the action of other muscles. Thus the performance of each pattern of movement is attended by a specific patterning of muscle action designed to control the positioning of the bones involved in that movement. This very complicated reflex action of stabilization is subject to continual change in the course of movement.

The

indirect concentration

individual cannot direct

on the movement

it;

his only influence

is

he wishes to perform.

The Stretch Reflex The

stretch reflex

is

a proprioceptive

phenomenon — that

is,

a motor

response to a proprioceptive sensation — which involves the reflex contraction of a

muscle subjected to a pulling force. It functions to protect importance in maintaining equilibrium, and often en-

joints, is of great

hances a movement

(for instance, in

the preparatory part of kicking or

when the leg or arm is moved back to place a pull on the flexor muscles). It may also serve as a restraining force when muscles antagonistic to movement are overdeveloped and therefore contract sooner than normal throwing,

in response to stretch.

The

stretch reflex protects a joint

when weight

and

its

ligaments against damaging

an outside force on the joint tends to produce The stretched muscles respond by contracting to maintain the integrity of the joint. The knee joint perhaps more than any other needs the protection of the stretch reflex, since it is frequentstrain

thrust or

other than natural movement.

144

PRINCIPLES OF

ly

subjected to blows or strong pressure against

MUSCLE FUNCTION its

145

outer side in vigorous

activities.

Maintenance

of'

equilibrium in the standing position

is

largely accom-

plished by reflex contraction of muscles in response to stretch as the threat of skeletal imbalance results in pull

Steinhaus, "The stretch reflex

on various muscles. According

to

may be

out of which the posture garment

is

considered as the substance of cloth fashioned" (78, p. 113).

Control of Muscle Action

According to Gray,

"It is

seldom possible

for a

person to

make

a single

words, the movements, not the muscles, are represented in the central nervous system. As Quain

muscle contract

at will" (33, p. 381). In other

states, "In the cerebral cortex

movements that are pictured, not The statements of these two anatmovement patterns requires concentration it is

the

individual muscle actions" (66, p. 9).

omists suggest that learning

on the desired effect of muscle action and not on the muscle action itself, it. The desired effect may be (1) voluntary performance of a movement or movement pattern, (2) ideokinetic neuromuscular coordination without conscious direction, or (3) the action of a single motor unit

or any part of

of a muscle.

Impossible as it may seem, this last phenomenon was demonstrated by Basmajian (5) electromyographically. The ability to activate a single motor unit can be developed through training, whereby the mild proprioceptive stimulation induced by the presence of the needle electrode in the motor unit is augmented by sensory reinforcement, such as audio and visual stimulation of the recording apparatus. This sensory reinforcement, necessary in the early training period,

becomes superfluous with time. Many

of the aspects associated with this training resemble those of the condi-

tioned reflex.

A

muscle can also be trained to perform movement which is opposite in direction to its normal activity. This phenomenon can be observed in muscle transplanted to alleviate muscular weakness, such as that caused by a poliomyelitis infection. Wright reported that "... in case of anterior tibial weakness, the peroneus longus is frequently put forward to take its place. At first the patient is unable to contract the transplanted muscle. Reeducation consists in telling him to perform the movement of pronation. This causes the peroneus longus to contract, but also the peroneus brevis. The resulting movement is jerky and hesitating, but if the peroneus longus had normal power before it was transplanted it prevails in its new function over the peroneus brevis and dorsal flexion, not pronation, occurs" (92, p. 23). Note that in the reeducation process the patient was asked to per-

form movement, not

to contract a muscle.

In neither of the above situations did the subject have absolute vol-

146

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

untary control over muscle action. His "voluntary control" w^as limited to whether he would or would not concentrate on performing movement. Only

by practice with a definite thought in mind was success finally achieved how it was accomplished by action in the central nervous system could not be determined in either case. For this reason the author does not consider that there can be "direct" control of action in a single motor unit of a muscle, in many motor units of muscle, or in many muscles, to any greater extent than occurs with all voluntary movement. Movements, not muscles, are represented in the central nervous sytem. Ideokinesis, as attained through imagined movement, relies on the principle that movement patterns are formed and stored in the central nervous system. Experimental evidence shows that concentration on visualizing a movement without trying to perform it voluntarily results in statistically significant changes in bony relationships (see Chapter 17). Hence sub-cortical patterning of muscle action in response to cortical activity must effect the movement essential to change bony relationships (83). Acceptance of the principle stated by Gray and Quain as a philosophy of teaching movement would shift the emphasis from indiscriminate and persistent admonitions about muscle tightening toward a more meaningful but just

attempt to achieve a concept of the desired skeletal movement pattern. In is all too often placed on tightening specific muscles, and some dance teachers and dancers consider it a weakness if there is not continuous effort to hold muscles taut. This approach reflects, above all, poor husbandry of energy.

the dance emphasis

Cortical Control

and Reflex Action

As Hellebrandt noted, "Every volitional movement is composed of two which is willed or cortically controlled, and that which is evoked spontaneously in association with the purposive act and cannot be intro-

parts, that

spected" (38, p. 57). This statement of principle implies that a desired in the thinking center of the brain

and

that

its

movement

is

initiated

successful performance

function of activity in the nervous system below the thinking level.

coordination of muscle action to produce a desired the skeletal structure during the process

movement and

is

a

The

to stabi-

patterned in the central nervous system in response to ideation and a continuous stream of impulses from the various sense organs of the body. lize

is

Steindler has stated that the stabilizing and equilibrating efforts which do not manifest themselves in visible motion play the most important part in locomotor performance (76). No movement can be successful without a multitude of reflex actions which have been established in the neuromuscular system in the course of man's phylogenetic development. These reflexes are the greater part of all purposive movement; they cannot be

MUSCLE FUNCTION

PRINCIPLES OF

147

them occur without recognition or definite They are the part of volitional movement

willed or directed, and most of

awareness by the individual. "evoked spontaneously in association with the purposeful act." As Hellebrandt states, "Sherrington has said that when we know how the mind makes itself felt on running the reflex machinery (of movement) we will have gone a long way toward understanding the basis of motor learning" (39, p. 12).

Group Innervation and Timing of Muscle Function Wright

cites various principles of

muscle function

set forth

by Beevor,

Lombard, and other pioneers in the early study of muscle function (92, pp. 6-26). Among these functions are muscle grouping and timing. Muscles are innervated functionally, with the result that they act manner to produce movement. Duchenne, in his preface to Physiology of Motion states that "isolated action of the muscle together in an orderly

group of muscles which contract to produce a movement, some begin their work early and some later, so that they act in sequential order; and the number of muscle fibers contracting in each muscle is determined by the degree of effort needed for the movement. If sudden strong effort is required from the beginning of movement, more muscles take part at once with more of their fibers in is

not in the nature of things" (23, p.

xviii).

In a

action.

Grouping of muscles for movement, the number of fibers contracting and the time of entrance of muscles into the work of movement

in each,

are patterned in the central nervous system.

among

The

result of such patterning,

it is dependent on the quality of the nervous system. The above principle was examined by Basmajian (5) in his electromyographic studies of the time sequence of muscle activity in flexion of the elbow. He concludes that (1) there is a fine interplay of action between the biceps brachii, the brachialis, and the brachioradialis; (2) there is a wide range of response in any one muscle; and (3) the path of muscular activity from start to finish proceeds in a random manner. He does not state whether the movements studied and the controls imposed on them were the same as those of Beevor, Duchenne, and others. One of the controls in the study of any movement pattern is the pull of gravity. If this varies in repetition of a movement pattern, muscle participation in the act will not be dupli-

timing in particular, differs

individual persons, for

cated.

Reciprocal Innervation Skeletal muscle acting on a joint is matched by other skeletal muscle producing an opposite action on the same joint. As we discussed in Chapter 2, muscles which produce movement are called agonists, or prime movers.

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

148

movement— that is, are capable of producing movement — are known as antagonists to the movement.

while those which opposite

The

resist

functional relationship of muscles

other in

movement

is

which are antagonistic

to

the

each

stated as the law of reciprocal innervation; as con-

prime mover, contractile activity diminishes at an However, the person involved must either voluntarily perform the movement or concentrate on the idea of the movement, visualizing it as it progresses, in order to bring this principle into action. If movement is produced by an outside force, the action of antagtraction progresses in a

equal rate in

onists to the

its

antagonist.

movement

not thus reciprocally inhibited, therefore the

is

contraction of the antagonists against the

stretch reflex activates the

movement. To compare resistance

to movement in these circumstances, ask a Then flex his ankle for him and note that the

subject to flex his ankle.

degree of flexion is less than the subject can attain through his own efforts. Hunt has described a method of increasing range of movement by applying resistance to a voluntary movement (45). She cites many exercises in

which strong resistance

is

apphed

to the

movement

either

by the subject

himself or by another person, with a resulting increase in range of move-

ment

after the resistance

is

removed. According

to

some dancers who have

tried this procedure, the results are not retained; they are evident only

immediately after the movement has been performed against restraint. This author has not used this procedure and hence reserves an opinion on it. One caution, however, should be observed in its practice — that of encouraging a

wrong use

of

some other

part of the body during the

perform movement against resistance, especially resistance applied by the subject himself. Because the habits of neuromuscular coordination used in these resistance exercises are not perceptibly changed toward increased efficiency, they no doubt fail on that account to produce lasting effects on range of movement. effort

to

In the posture laboratory

it

has been shown repeatedly that increase

neuromuscular coordination through ideokinesis (visualized movement without conscious voluntary direction) is a reliable means of increasing freedom and range of movement. in efficiency of

Muscle Function Relation of Muscle Function Resting Length

The resting length of any muscle is its length when the joint or joints whose movement it influences are in neutral position (see p. 13). Some muscles coordinate their action most effectively with others when they

PRINCIPLES OF

MUSCLE FUNCTION

149

movement (as by the by the abdominal muscles during movement of the limbs). This does not mean that these muscles cannot contract from an elongated position, but to do so they must exert more power and their coordination with other muscles is thus not ecocontract from their resting length, either to produce flexors) or to stabihze skeletal relationships (as

nomical.

Some muscles must be elongated from their resting length before they can act either to stabilize joint position or produce its movement. Examples of these muscles are the extensors of the head, trunk, and extremities, all of which must be elongated before they can contract. Jumping would be impossible if joints of the lower extremities were not first flexed to stretch the extensors

An example

beyond

their resting length.

of failure to observe this principle of action of the extensor

found in the exercise often prescribed to strengthen the gluteus lying in the prone position, in which the gluteus maximus has not been lengthened. When the extended lower limb is lifted backward as recommended, the gluteus maximus does not contract to produce the

muscle

is

maximus while

movement;

its

action

is

restricted to support of the thigh.

results in hyperextension of the in the anteroposterior

tilt

The movement

lumbar spine with simultaneous increase

of the pelvis as a result of the action of the

The proper

Y

which to accomplish the above intent is with the person resting in the prone position on a table of proper height, thighs flexed and feet resting on the floor. In this position the gluteus maximus is elongated, and it must contract to raise the thigh backward to a horizontal position against the pull of gravity or any imposed resistance. The concept of the resting length of muscles — length as it would occur in the standing position with all first-class weight-supporting bony levers

ligament on the front of the femoral

in

joint.

position from

mechanical balance — is important in determining procedures in the

posture laboratory, especially those in which the abdominal muscles are to be improved in strength and coordination with other muscles. Synergistic Action of Muscles

Many

muscles have more than one action on a joint; and when they all these actions unless prevented by some force,

contract they produce

which

is

frequently the action of other muscles

known as synergists. In movement of a joint —

a physiological group of muscles cooperating in the for instance, flexors of the

flexor muscles calls

may be

femoral joint — undesired action in one of the

antagonistic to undesired action in another. Wright

these muscles "helping" synergists (92) and cites as an example the

tensor fascia lata, which flexes and rotates the thigh inward, and the sartorius,

which

flexes

and rotates the thigh outward. Their mutual action

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

150

and in so doing stabiHzes the joint which such muscles provide mutual synergistic action depends on the desired direction of movement. Another example which Wright cites is the triceps muscle, whose action as an extensor of the elbow prevents its flexion by the biceps brachii when flexes the thigh but cancels rotation

The extent

laterally.

this

muscle contracts

triceps

is

to

to supinate the

hand. In

this situation the action of the

purely synergistic.

There are other muscles which act as synergists but simultaneously exert restriction on the movement. In such situations the prime movers of the joint are sufficiently strong to overcome the slight restriction of the synergist.

The cooperative

action of muscles acting as synergists in a

movement

is

a separate process from the continually changing stabilizing action of

muscles which support the success of a desired movement. Two-Joint Muscle Function

Some muscles

of the

upper and lower extremities, known as two- and movement in two or more joints. Their

multi-joint muscles, influence

same action, either flexion or extension, in all the joints whose movement they influence (92, pp. 8, 10). Their primary action is on the distal joint, where they have better leverage. The arrangement of these muscles in relation to the joints promotes economy of energy. In the lower extremities, in such movements as walking, running, leaping, and jumping, the two-joint muscles function to produce like movement in the femoral, knee, and ankle joints. In these locomotor movements joint extensions are needed in the supporting limb while joint flexions are needed in the forward-moving limb; in jumping, extension of joints is needed to lift the body, but flexions are then needed in preparashortening produces the

tion for landing

As important

from the jump. as two-joint muscles are, they cannot function effectively

without simultaneous action of one-joint muscles, nor vice versa. The cooperative work of one-, two-, and multi-joint muscles enables a person

on

and

hang by

even though the muscles in little innate power. "Tendinous action" and "ligamentous action" have been ascribed to opposite ends of two-joint muscles. Through tendinous action the power of one-joint muscles is transferred distally through a two-joint muscle; through ligamentous action, overaction in the joints is prevented. For example, when the one-joint extensors of the thigh begin to extend the thigh, a pull is exerted on the two-joint muscle on the front of the thigh — the rectus femoris — which results in its exerting tendinous action on the knee to extend it. The extension of the knee exerts a pull on the two-joint muscle on the back of the leg, the gastrocnemius, which results in its exerting

to stand

his toes

to

his hands,

these distal parts are relatively very small and have

PRINCIPLES OF

tendinous action on the ankle joint to extend

it.

MUSCLE FUNCTION

151

As the extension

of the

completed, ligamentous action of the proximal ends of the twojoint rectus femoris and gastrocnemius muscles comes into play to prevent joints

is

overextension of the thigh and knee

joints.

of one-joint extensors of the femoral joint

is

how

This explains

the

power

transferred to the use of the

jumping or in standing on the balls of the feet. In pulling and pushing movements, the ligamentous action of two-joint muscles is of great importance to the integrity of the very loose shoulder foot in

movements the

joint. In pulling

two-joint biceps brachii exerts both tendin-

ous action to supinate the hand and flex the elbow and ligamentous action on the top of the shoulder joint to aid in holding it in its socket. In pushing

movements, the two-joint triceps muscle exerts tendinous action to extend the elbow and ligamentous action on the lower part of the humeral joint to aid in

maintaining

its

position in

its

socket.

Two-joint muscles in emergency will assist in joint.

For example,

will assist in the (1)

of

if

thigh flexion

is

movement

of the

upper

resisted, the two-joint rectus femoris

movement. There are two exceptions

to this general rule:

the biceps brachii will not aid the flexors of the humeral joint regardless

what

resistance

may be

given to this movement, and

not aid in thigh extension unless the line of gravity

(2)

hamstrings will

falls in

front of the

thigh joint (92, p. 11). In a rise from a deep squatting position with the

trunk upright, as in the deep plie of the dance or as sometimes unwisely

weight from the ground, the hamstrings will not assist; bent forward so that the line of gravity falls in front of the center of the femoral joint, the hamstrings take part in the extension of advised for

but

if

lifting

the trunk

this joint.

This

is

work

of the hamstrings

is

of great advantage in stooping

movements.

To experience the action of multi-joint muscles on the arm, wrist, and hand, rest the elbow on a support and try opening and closing the hand

when

the wrist

is

extended and when

it is

flexed.

Only a

slight

movement

of the wrist in flexion or extension will bring passive opening or closing of

the hand, because of the shortness of the multi-joint muscles which exert greater tendinous action than the longer two-joint muscles.

When movements of adjacent joints of the limbs are incompatible, the proximal end of the two-joint muscle acts as a ligament to resist movement of the upper joint. This explains why adequate range of movement in the grand battement en avant is so difficult for the dancer to attain at first. The two-joint hamstrings on the back of the thigh give strong resistance to flexion of the femoral joint when the knee is straight. The hamstrings yield spontaneously to

some

extent, but the tighter they are, the less they

performance of the movement. One of the best ways to ensure their normal length is through better balance at the lumbosacral and femoral joints, so that most of the time in the standing position the line

will yield in the

152

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

behind the center, of the Further means of lengthen-

of gravity falls through the center of or slightly

femoral joints, never persistently in front of

it.

ing the hamstrings are described in Chapter 23.

Wright summarizes the advantages of two-joint muscle action as follows: the transfer of power of one-joint muscles to distal joints (tendinous action); (2) the protection of the upper joint when both joints are vol(1)

untarily extended or flexed (ligamentous action);

give in emergency in (92).

movements

of the

upper

and

(3)

joint over

the help they

which they pass

15 The Role of the Nervous System

The nervous system

initiates, regulates,

and monitors

Movement

in

all

movement by and

within the body. All self-movement proceeds on impulse from the nervous system. Such impulses

may be

originated voluntarily or involuntarily, from

the conscious or unconscious.

They may be responses

to exteroceptive,

interoceptive, or proprioceptive stimuli.

Movement control is just one of many functions of the nervous system. The nervous system is also the seat of man's emotional, intellectual, and creative endeavors.

It

provides a storage and retrieval system that finds

memory bank which not only can recall the experiences of times past, but also can acquire new experiences and draw from each for the synthesis of new knowledge or more meaningful interpre-

no

rival. It

serves as a viable

tation of the arts or of the

unknown.

Men

have attempted

certain percentage of the nervous system's activity to

to ascribe a

movement

control,

but so far they have not done so successfully. The harmonious interplay of

many

diverse activities within the system defies quantitative separation.

The Central Nervous System Structurally, the nervous system has

been

arbitrarily divided into the

and peripheral nervous system. The central nervous system consists of the brain and the spinal cord, and the peripheral system consists of the multitude of nerve fibers and end organs which permeate the entire body. The brain is completely enclosed in the cranial cavity and is divided into two major sections, the cerebrum and rhombencephalon. The cerebrum is further divided into the forebrain and midbrain (see Figure 53). The cerebrum is a somewhat ovoid mass divided by a sagittal cleft into right and left hemispheres. Superficially the hemispheres appear as highly convoluted and furrowed masses of tissue which supply the cerebrum with a central

vastly enlarged surface area.

A

surface layer of gray cells, called the cere-

bral cortex, covers each hemisphere.

It

coordinates and promotes

all

con-

153

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

154

BRAIN

THALAMUS QUADRIGEMINA HYPOPHYSIS

PONS CEREBELLUM ATLAS

ODONTOID PROCESS OF AXIS wmmn SPINAL CORD -#i LIGAMENTUM NUCHAE

BODY OF 3RD CERVICAL VERTEBRA Figure 53.

scious

The

and

brain, sagittal section, in situ.

volitional activity.

The multitude

by the cortex has been traced with functional charts or

maps

divisions assigned to the

sufficient accuracy to

for the cortex.

many

of activities that

activities.

is

controlled

permit us to draw

These maps show

territorial sub-

Informative as they are, they do

not convey a clear picture of the complex

phenomena

of nervous system

interactions.

Various basal ganglia are located deep in the cerebrum and around the brain stem, each having its own special part to play in man's general behavorial responses. the quadngemina,

Among them

and the

are the thalamus, the hypothalamus,

colliculi.

The hypothalamus,

serves as an integration center for emotional expression.

for It

is

example, also con-

sidered to be the central thermoregulator, helping to maintain normal

body temperature

in response to

thermal changes both inside and outside

the body.

The cerebellum, cephalon,

is

or small brain, a major

component

located dorsally under the cerebrum.

It

also

of the is

acterized by a multitude of convolutions, with an outer cortex of densely

packed gray

cells.

The cerebellum

is

composed

a coordinating center for

impulses originating in other parts of the nervous system. activity and maintains balance.

muscle

rhomben-

a tissue, char-

It

monitors

THE ROLE OF THE NERVOUS SYSTEM

The

IN

MOVEMENT

155

a composite of separately identified regions— the

brain stem,

midbrain, pons, and medulla oblongata — serves as a connecting Hnk be-

tween the cerebrum, cerebellar complex, and the spinal cord. The spinal cord (see Figure 54) is an elongated, thick, cordlike structure located in the spinal canal. It extends to the level of the first lumbar vertebra where it ends in the cauda equina, which is made up of nerves which exit from the spinal column at various lower levels. The spinal cord is composed principally of two parts: an inner segment of gray matter surrounded by an outer layer of white substance. The white substance is nerve fibers which carry either sensory or motor messages to and from the brain; the gray substance, shaped something like an H inside the white substance, is composed of cell bodies and their unmyelinated processes.

The Peripheral Nervous System

The system nerve

between the central and the peripheral nervous proportion of the functionally active components of the

essential difference is

one of

tissue.

The

central nervous tissue contains a multitude of nerve

and fewer nerve fibers, structurally supported by functionally inert cellular components, connective tissue. The peripheral system consists mostly of nerve fibers and their end organs. Comparatively few neurons are found in the peripheral system, and these are concentrated in the ganglia of the autonomic nervous system. cells,

or neurons,

POSTERIOR GRAY

COLUMN ANTERIOR GRAY

COLUMN

GRAY POSTERIOR NERVE

ROOT SPINAL

GANGLION ANTERIOR MEDIAN

ANTERIOR NERVE

FISSURE

ROOT

Figure 54. Schematic drawing of a spinal cord section, front view, showing roots of two nerve fibers.

156

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

The nerve

convey sensory messages from the sensory receptors to the central nervous system, or carry motor messages from the central nervous system to the muscles. These fibers continue, unbroken, from their cell body to their destination. A fiber can serve in one capacity only: it can transmit either a sensory message or a motor message: It cannot fibers

transmit both.

The end organs of the

peripheral system

may be

either sensory receptors, which respond to environmental changes, or motor end plates, which transfer motor messages to muscle fiber. Motor end plate is really a misnomer; it is not a plate but rather a multiple junction of branches of a motor nerve with muscle fibers. The peripheral system consists of 12 pairs of cranial nerves, 31 pairs of spinal nerves, the autonomic nervous system, and its

ganglia.

The

cranial nerves originate in

the brain stem and fan out both to the facial

sensory receptors and to the complex and expressive musculature of the head and

The spinal nerves permeate the limbs and trunk to serve in their assigned capacity and area. The autonomic nerves carry out similar functions in the smooth face.

tissues of the vital organs.

The Autonomic Nervous System Functionally the nervous system

may be

divided into the voluntary (cerebrospinal)

and the awtonom/c nervous system. Anatomboth systems have much in common. The major difference is the larger number of ganglia, an aggregate of neurons, and the presence of plexuses, networks of interlacing fibers, in the autonomic nervous system (see Figure 55). Many of the ganglia and of ically

Figure 55. Anterior surface of the spinal cord with spinal nerves and ganglia of autonomic nervous system.

THE ROLE OF THE NERVOUS SYSTEM

IN

MOVEMENT

157

the peripheral plexuses' origins are found in the sympathetic nerve trunks,

which extend vertically along each side of the vertebral column. As their names imply, the voluntary system presides over the voluntary muscle functions, while the autonomic system innervates the smooth and cardiac muscles as well as glandular tissue. The basic difference between these two systems is the relative ease with which each responds to voluntary commands. It is relatively simple to stop a movement of the hand from putting food into the mouth; it is virtually impossible voluntarily to increase or decrease peristalsis. The autonomic nervous system monitors and regulates continuous physiological and metabolic activities so consistently that the whole process is autonomous. The muscular work patterns have become deeply ingrained and resistant to change. Yet preliminary studies made by laboratory clinics indicate that through training people can control their heart beat and lower their blood pressure (19, 20). It seems, therefore, that as more becomes known about the way the nervous system works and how changes can be produced, it may become possible not only to improve means for neuromuscular reeducation in the voluntary nervous system but also to develop means to correct anomalies in the autonomic nervous system.

The Neuron The nerve

cell

and nerve

fiber are both intimately associated with all

nervous system. Of the two, the nerve cell, or neuron, is the lone operant unit. The nervous system contains approximately 10 billion activity of the

neurons, and about 90 percent of these are located in the brain. Each

neuron

is

a miniscule yet highly sophisticated

work

unit. It

can

initiate,

coordinate, transmit, receive, or inhibit stimuli as necessary for the per-

formance of the complete range of man's activities. With all its complex functions, the neuron may justly be called the basic element of man's intelligence and motor function. The neuron (see Figure 56) is anatomically an independent unit. It usually has a somewhat irregularly shaped cell body filled with reddish gray cytoplasm. Its large nucleus contains a prominent nucleolus, and its cytoplasm contains mitochondria, neurofihrillae and Nissl granules. The periphery of the cell body is further characterized by numerous cytoplasmic projections called dendrites.

The

and then further subdivide into a multitude of branchlets; thus they contribute markedly to the total surface area of the neuron. They receive and conduct stimuH or impulses toward the central neuron body. Because messages flow through the dendrites toward the cell body, the dendrites are called the dendrites, though often sport, tend to branch

afferent fibers of the neuron.

158

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

^

DENDRITE TERMINAL KNOBS

AXON NUCLEUS NUCLEOLUS

AXON Figure 56. Schematic drawing of the motor neuron.

The transmission of stimuli from neuron to neuron is not direct but way of yet another process, the axon. The axon is a tube or fiber-

occurs by

like projection. It

may be

short but

is

often long, terminating in a spray

of short branches, each characterized by a small terminal knob.

are the transmission lines of the nervous system.

The neuron

The axons

fires

impulses

along the axon which then transmits these impulses to the surface of another

neuron, be

it

directly

final destination

— the

on the

cell

body, to a dendrite of the

cell,

or to their

surface of a muscle fiber. Except for certain sensory

neurons, the axon conducts messages

away from

the cell body and

is,

therefore, called the efferent fiber of the neuron.

The term motoneuron

is

often used to describe nerve cells

whose

axons innervate the extrafusal fibers of voluntary muscles. The term sensory neuron refers to nerve cell which acts as the primary receptor of a

sensory impulse.

Operation of the Nervous System Impulse Transmission

The transmission

of a nerve impulse from nerve cell to nerve cell or muscle fiber occurs at points of intimate junction, the synapses (see Figure 57). Electron microscopic examinations have revealed that there is no direct contact between the cell membranes, and that the cleft separating the presynaptic from the postsynaptic membrane measures a mere 150 to 400 angstroms (25, 26). Each nerve cell may receive impulses from many nerve cells through a multitude of synapses. Thus one neuron may receive information from a few to as many as 100 or more other neurons. It then transmits the composite of these impulses to many other nerve cells or muscle fibers through the end branches of its axon. There are two types of action at the synapse:

from nerve

to

THE ROLE OF THE NERVOUS SYSTEM

IN

MOVEMENT

159

and inhibition. Impulses causing excitation or inhibition may be entering the same nerve cell at the same time. The effect of each type of impulse is cumulative, and it is the total of both effects that determines whether the impulse is to go on as is, be modified, or be canceled. It is impossible for a nerve cell to transmit both types of impulses. The actual transmission of impulses from cell to cell or to muscle fiber is an interesting, complex phenomenon which has been the subject of many studies (2, 24-26, 51). The nerve impulse which is propelled down the axon comes to a complete halt at the synapse. For the impulse to continue, it has to be re-established on the far side of the synapse. This apparently hopeless task is accomplished through an ion exchange mediated by a chemical transmitter substance. We shall not attempt to discuss the ion exchange mechanism in detail. In general, nerve cells and muscle fibers when at rest maintain an unequal distribution of ions between their intracellular and extracellular medium. The concentration of sodium and chloride ions is higher on the outside, while the concentration of potassium ions is higher on the inside. The result is that the potential of the nerve cell at rest is negative with regard to the outside medium. The voltage differential is approximately 70 millivolts. When excitatory impulses reach the synapses on the cell body or the dendrites of the receiving cell, vesicles containing a chemical trigger excitation

substance are discharged into the synaptic increases the ionic permeabihty of the cell tion or reduction in

membrane

cleft.

The

trigger substance

membrane through

depolariza-

As the depolarization reaches the cell while a few potassium

potential.

a critical level, sodium ions surge into

-AXON CYTOCHROME VESICLES WITH

TRIGGER SUBSTANCE PRESYNAPTIC MEMBRANE SYNAPTIC CLEFT K+

-»->•-»• -h H-

POST SYNAPTIC -H-^

^^^i^^-e^t^^ic:^^Plx

^ I Figure 57. Synaptic transmission of nerve impulses.

+ +

-t-

i-

+

+

MEMBRANE DENDRITE

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

160

ions diffuse out. This leads to a

sudden voltage spiking within the

cell,

and the impulse is reestablished. Although there may be more than one trigger substance in synaptic transmission, the only one positively identified to date is acetylcholine. When its action is complete, it may diffuse into the surrounding medium, but most hkely it will be destroyed by the enzyme cholinesterase.

When The

inhibitory impulses reach the synapses, the process

membrane

cell

is

is

reversed.

hyperpolarized, potassium ions surge outward, and

sodium ions slowly diffuse into the cell. A chemical trigger substance for this process has been postulated, but none has been positively identified. In the neuromuscular transmission of impulses, each motor nerve fiber divides into many terminals whose end organs are distributed onto a considerable number of muscle fibers, with each motor nerve fiber serving its specific territory of muscle fibers. At least two types of motor nerve fibers have been identified (see Figure 59): a large fiber, the alpha fiber, v^^hich innervates the extrafusal muscle fibers; and a small fiber, the gamma fiber, which innervates the intrafusal fibers of the sensory spindle (31). The impulse transmission is mediated by acetylcholine in much the same manner as that described for transmission from nerve cell to

nerve

cell (62).

The above

description of synaptic transmission fails to portray the com-

plexity of the entire process.

The speed and accuracy with which impulses

are transmitted, modified, or inhibited cannot be matched by anything

man

has invented. Yet the system

plastic. (51).

Were

it

is

not locked in but remains inherently

not so, neither our habits nor our behavior would

be tractable and learning would be impossible. Sensory Receptors

The sensory receptors serve as the ecological monitors for the nervous They detect, report, and elicit responses to environmental con-

system.

ditions as they

the body (58). limitless.

impinge on the outer surface of the body or occur within The range of stimuli which the receptors pick up is almost

The notable exceptions are x-ray, The acuity with which various

irradiation.

ultraviolet rays

and radioactive

stimuli are recognized

is

often

and usually decreases with age. The overall effectiveness of the senses may be impaired by chemical agents or overstimulation. Loss of hearing, for instance, can often be species specific, varies from individual to individual,

traced simply to too

much

noise. Structurally, the sensory receptors vary

from simple free nerve endings

to bulblike structure and corpuscles. Sherrington (72) has classified the sensory receptors into three groups according to their location: the interoceptors, the exterocepters, and the

proprioceptors.

The

interoceptors monitor the alimentary tract and viscera. There are

THE ROLE OF THE NERVOUS SYSTEM relatively

few

of them,

IN

MOVEMENT

and they are particularly well suited

161

to pick

up

chemical stimuli.

The exteroceptors such, they receive

are the peripheral outposts of our awareness. As and transmit stimuli acting upon the body from without

can respond to changes in the external environment. A veritable army of these receptors serves our senses of taste, smell, hearing, sight, and touch. Each sense is supplied with its own specific receptors. There

so that

it

are receptors which respond to the sensation of heat only, while others

respond

to cold only;

no receptor can respond

to

both stimuli. The nerve

impulses produced by the exteroceptors normally scious level

rise

and produce well-defined sensations. At

cortex integrates and correlates

all

above the uncon-

this point the cerebral

the exteroceptive impulses by taking

and the memory of past experiences. and possibly some basic unity of the

into account both the actual impulses

Through

training, experience,

senses, the receptors of

one sense may report

for those of another.

For

tell us whether it is solid or not, and yet this decision can only be made by the sense of touch. A deaf person can learn to translate the visual impression of the movement of lips into spoken words, and the bHnd person learns to move about aided by the sense of touch. The three senses of hearing, sight, and touch are extremely important not only in reporting environmental changes but also in helping man move within his environment with the proper appreciation for distance, space, and balance. The proprioceptors monitor the perpetual internal changes occurring to keep the body in balance and motion (36). They respond to changes in muscular activity; and, once movement has been learned so that it pro-

instance, a look at an object will usually

ceeds automatically, their impulses rarely penetrate our consciousness.

According to Ranson (67), only one of the afferent nerve fibers transmitting impulses from these receptors terminates in the cortex; all others end in

The manner in which the spindle proprioceptors receive and respond to stimuli is almost as intricate, delicate, and complex as that of any sensory organ, especially the visual and auditory. The major types of proprioceptors are the Pacinian corpuscles, the labyrinthine receptors, the Golgi tendon organs, and the muscle spindles the cerebellum.

(see Figure 58).

The Pacinian Whether serving

corpuscle, the "touch" receptor,

is

the most ubiquitous.

an exteroceptor or a proprioceptor it is found in the skin of the hands and feet, in the tendons, in intermuscular septa, and in large numbers around the joints. Irregularly prolate and of various sizes, it responds to mechanical stimuli such as pressure and other stress and as

facilitates reflex responses. Structurally, the corpuscle is

of lamellae of connective tissue surrounding a

The labyrinthine

made up

of series

nonmyelinated nerve

fiber.

receptors, a vestibular apparatus, are part of the inner

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

162

SEMICIRCULAR

CANALS ANTERIOR POSTERIOR UTRICLE

LATERAL

SACCULE A.

B.

NERVE FIBERS

MUSCLE FIBERS

I

PRIMARY

NUCLEAR CHAIN FIBER

U4 /

Tapsule

NUCLEAR BAG FIBER POLAR REGION

NUCLEAR bAg REGION

YOTUBE REGION EQUATORIAL REGION

K

POLAR REGION

D. Figure 58. Proprioceptor sensory organs. (A) Pacinian corpuscle. (B) Labyrinth. (C) Golgi

tendon organ. (D) Muscle spindle.

THE ROLE OF THE NERVOUS SYSTEM

IN

MOVEMENT

163

They give us poise and stability in all our movement and are exquisitely tuned space sensors. All proprioceptive activity occurs

ear structure (90).

within sections of the fluid-filled canals,

and the

utricle of the ear.

membranous labyrinth, the semicircular The semicircular canals are oriented in

the planes of the three space coordinates; each canal contains receptors

whose sensory

hairs float in the fluid.

movement

head or body

to

of the

is

Movement

in the fluid in response

signaled to the hairs and then relayed

to the receptor. In the utricle the sensory hairs of the receptors

extend

and fan out among numerous crystals of calcium carbonate, the otoliths. Any shift in head or body position causes a shift in the crystal position, resulting in displacement of the sensory hairs and subsequent stimulation of the receptor. The impulses from the labyrinthine receptors initiate compensatory reflex action of eye muscles, body, and limbs without entering the realm of consciousness.

The two proprioceptors which muscular

activity

and which appear

are most intimately associated with to

work

in

the Golgi tendon organs and the muscle spindles.

synchronous harmony are

The Golgi tendon

organs,

the neurotendinous spindles, are primarily located near the insertion of

tendons into muscles and near the insertion of muscle spindles. These are encapsulated structures containing tendon fibers. The nerve entering the capsule branches and terminates in a spray of knobs interspersed the tendinous fibers.

The Golgi tendon organs

among They

are tension recorders.

are able to record tension of contraction or of stretch of muscle, and their rate of excitation varies in proportion to the

corded.

They are the

amount of tension being rewhich prevent the muscles

origin of inhibitory reflexes

from reaching dangerous levels of tension of contraction in response to stretch. In this respect, they inhibit their own muscles and facilitate the antagonists.

is

Probably the most refined and complex sensor of muscular activity The spindles are found throughout the mus-

the muscle spindle (31, 32).

cular tissue interspersed allel

alignment.

among

the extrafusal fibers of the muscle in par-

They are spindle-shaped

capsules, each spindle containing

which may be of two distinct two types of intrafusal fibers is called the nuclear bag fiber. It is characterized by a centrally or equatorially located enlarged nucleated area, the nuclear bag, which has sensory capabihty. The polar regions of each fiber are striated, but the striation diminishes on both sides of the nuclear bag (the myotube region) and disappears completely in the nuclear bag area. This leaves us then with a muscle fiber which is contractile in the polar region, mildly contractile in the myotube region, and noncontractile in the sensory center region. The second type of fiber, the nuclear chain fiber, is smaller and more slender than the bag fiber. In the chain fiber, a nuclear chain replaces approximately four to

six intrafusal fibers

types according to both size and shape.

The

larger of the

164

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

the nuclear bag at the center; nevertheless the fiber exhibits the same pattern of contractility (31, 32).

The spindle, having both contractile and sensory capabihty, is supplied with both afferent and efferent fibers; and each intrafusal fiber is supplied w^ith both sensory and motor end organs. The afferent sensors form two systems: the primary, or annulospiral, and the secondary, or flower spray. The primary system spirals around the nuclear bag or central portion while the secondary system distributes its flower-spray endings over the myotube region. The afferent nerves of the primary system are quite large; those of the secondary system are small. Multiple motor nerve endings are at both polar regions of each intrafusal fiber. These motor nerve endings are predominantly those of the gamma fibers which, as stated earlier, are smaller than the alpha motor nerve which terminates primarily in the extrafusal motor fibers (see Figure 59). Given both the structure and the motor nerve supply of the spindle fibers, they must be contractile. This contractihty, however, is limited to the polar region. The center area, the nuclear bag or chain, not being striated, does not contract and is stretched during polar contraction. This stretch provides the necessary stimulant for the afferent nerve endings

which

sets the sensory

stretch in the fiber

fades over the

is

mechanism

into action.

The area most

sensitive to

the nuclear bag or central area, and this sensitivity

myotube

region.

The sensory

capacity, however, goes

responding merely to the extent of stretch;

it

also responds to

beyond

changes in

the velocity of the stretch.

EFFERENT FIBERS

V-ALPHA

Fll

EXTRAFUSAL

GOLGI

TENDON ORGAN

MUSCLE SPINDLE

AFFERENT FIBERS Figxire 59. Extrafusal

and

intrafusal

muscle fiber innervation.

FIBERS

THE ROLE OF THE NERVOUS SYSTEM Since the alpha and

gamma motor

IN

MOVEMENT

165

neurons do not necessarily work

synchronously, the muscle spindle lying between extrafusal fibers can

be subjected to stretch as the extrafusal fibers change in length. This stretch by displacement or misalignment is also recorded by the spindles. In summary, the muscle spindles, because of their rich innervation and unique structural design, are a most sensitive recorder of muscle stretch. In combination with other proprioceptors, they have supplied man with a most proficient and complete monitoring system for his muscular activity and balance. Reflexes

and Feedback Mechanisms

As indicated above, the sensory receptors must warn the nervous system and deviations from the norm which occur both within and outside the body. The stimuli impinging on the receptors are transformed into impulses which transport the messages inward into the nervous system for disposition and response (55). Most of the responses to these impulses occur involuntarily at the subcortical level. They facilitate muscular or other activity and are collectively called reflexes. of changes

Sherrington defined the reflex as "the unit reaction in nervous integration" (72, p. 7). This unit reaction initiation,

conduction, and effect.

may be

divided into three processes:

The chain

of events could likewise be

separated into reception, transmission, and reaction, with the transmission at least two neurons — one sensory and one motor. It must be understood, however, that this is a theoretical unit and that no reflex exists as a single-unit reaction. Instead each acts as an integrated composite of many units. Consider the turn of the head in response to a sudden sharp noise, and it will soon become evident that the reflex action is not limited to the turning of the head. Action pervades the muscular structure

phase containing

beyond the primary target area. There are two types of reflexes: innate and conditioned reflexes. Innate reflexes exist independent of any learning process; their connections in the central nervous system develop in advance of their use. For each, the stimulus and response are always the same. The conditioned reflex, however, is more complex. It is normally dependent on cortical activity before it becomes established as a reflex. It becomes firmly fixed with time as an integral part of automatic behavior. Thus the conditioning process continues throughout life, from infancy through old age. Changes in neuromuscular expression are always possible. In early life good or poor neuromuscular habits may be established through imitation; later on, they may be estab-

far

lished not only through imitation but also in response to

cesses

it is

movement

many

all life

situations

activities. In all

these pro-

the quality of the input that controls the quality of the

output— in

or the teaching of

this case, the

patterns in

conditioned reflex.

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

166

The most is

build ity.

component of movement and other teaching methods all too often

efficient conditioned reflex as a

difficult to attain. Imitation

up already established conditioned

In doing so, th^y retain

all

reflexes, regardless of their qual-

existing inefficiencies of

movement. In these

situations a re-patterning of established conditioned reflexes

is

needed,

which maintain upright equilibrium. The ideokinetic principle of teaching has been found to be most useful in obtaining such especially of those

changes.

The most important innate reflex is probably the stretch reflex (see Chapter 14), which is a reaction to proprioceptive stimulation, specifically to that of the muscle spindles. It is the basic control mechanism for coordination of muscular activity involved in movement and balance. Indeed it even supplies the muscle with self-regulating properties. The simple stretch reflex, which must be considered as a theoretical entity because it does not occur alone, is a monosynaptic or two-neuron reflex arc (see Figure 60). In this special situation, the impulse generated in the spindle excites the sensory neuron from whence it is propelled via a monosynaptic connection to the motoneuron. The motoneuron in turn excites the muscle in which the original stimulus occurred. But this is only part of the reflex action that occurs.

The axon from

other neurons, possibly via

di-

the sensory neuron branches and excites

or multisynaptic connections to facilitate

both synergistic and antagonistic muscular activity simultaneously (88). Basically the stretch reflex works on cue from the muscle spindles, which

respond to both degree and velocity of stretch. The reflex plays an important role in the orchestration of muscular activity and ensures that the muscles perform the tasks desired of them (59). Besides their role in the reflex mechanism, the sensory receptors and the impulses generated by trol.

Feedback control

man-made

or natural,

them are where

exists

is

also

an integral part of feedback con-

part of the output of a system, be

fed back to control the input.

It

GANGLION

SENSORY NERVE FIBER

MOTONEURON

MiiQniP MUSCLE

^Q^

MOTONEURON CELL BODY Figure 60. The simple reflex

arc.

it

functions to main-

THE ROLE OF THE NERVOUS SYSTEM

IN

MOVEMENT

167

tain the quality or quantity of the controlled output at the prescribed level

of output, irrespective of outside influences.

been recognized as a working principle last 40 to 50 years.

Feedback control has only

in the biological sciences for the

In the mechanical field the feedback principle

matic control systems.

One

is

is

the basis for two auto-

the regulator, for example, the thermostat

which a fixed output is sought which is independent of input variations. is the servomechanism, a mechanism which automatically corrects the performance of a second mechanism to a desired standard by an error sensing feedback. The automatic pilot or gun sight control are examples of servomechanisms. Feedback, at work throughout biological systems, is an integral part of neuromuscular coordination (28, 29, 39, 56, 59). Without it voluntary movement would be uncontrollable if not impossible, because it cannot be regulated only by efferent impulses from the brain to the muscles (the way a mechanical toy operates). The brain must receive feedback of the progress and range of movement and of the change in muscle tension so that it can adjust to them to achieve the goal of movement. This feedback consists of the diverse afferent impulses generated by the proprioceptors as the movement progresses. The need for feedback can be appreciated when one considers how difficult it is to start movement in a limb that has gone numb; the feedback is not working. Though many feedback messages terminate at subcortical levels or in the cerebellum, some reach the postin

The second

central sensory cortex. Injury to this part of the brain destroys the ability

perform well-organized movement (56). Although feedback both stabilizes and integrates voluntary movement, its own workings easily can be upset. A gymnast may forfeit a certain exercise in his performance because "it didn't feel right" or "he wasn't ready." A whole pattern of movement may be disarranged; try to continue dancing the waltz when suddenly the music changes to an atonal composition. Watch the gait of a blind-folded person who has momentarily lost to

the use of his eyes as feedback sensors.

would seem that if feedback can be weakened and distorted it should be amenable to reinforcement. Indeed, it is. Such reinforcement is possible through concentration, refinement of the concept of the ultimate goal, the help of visual aids or audiodevices, and through development of an awareness of the cues with which the sensory receptors supply us. It

also

Learning to

The process

Move

moving the body has been described earlier as the nerves exciting the muscles and the muscles moving the bones. This chain of action may sound simple, but it is not, because movement implies a continuous of

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

168

change

body and

in the

its

parts in position, direction, velocity,

and

force.

Movement being spread over a multitude of parts of the body becomes a horrendously complex process. This very complexity, however, also furnishes

man with a Capability for a quality and

only few utilize to the as

full extent.

Most

an innate property of the body; yet

quantity of motor

skills

of us accept the ability to

we seldom

which

move

consider the function,

the limitations, or the efficient use of movement.

Movement

from the integrated activity of the entire nervous system — the voluntary and involuntary, the afferent and efferent messages, modulated by innate and conditioned reflex activity and feedback mechanisms.

How

results

is

this ability for

learned, or both?

How much is

movement acquired?

Is it

hereditary;

autonomous, and how much

is

is it

not?

would seem that both heredity and learning are involved in movement. Moving in the upright position is surely species-specific for man. The heart beats in the embryo before birth, the embryo kicks reflexively, the mechanisms of respiration function immediately after birth, and so does peristalsis. The autonomous movement patterns essential for the survival of the organism are functional at birth. There is no clear evidence It

movement patterns for locomotion are as clearly defined at birth movement patterns essential to survival. It is probably correct, how-

that the as the

ever, to

assume that most

functionally competent.

of the sensory receptors are at least partially

They represent the

primitive hereditary tools of

learning and establishing neuromuscular coordination.

A recent study on the walking reflexes adds to our understanding of movement. Stimulation of the reflexes concerned in walking in the newborn leads to coordinated walking movements. If the bare feet of a baby, as he is held under the arms, touch a flat surface, he will perform well coordinated walking movements very similar to those of the adult. Stimulation of the sensory receptors in the soles of the feet elicit the synergy of movement of walking (93). Early learning occurs mainly through observation and imitation. The child between one and two years of age is a very devoted watcher, and we may infer that at this age he learns principally by observing and imitating. Thus, what we sometimes call instinctive behavior may at least be the product of intraspecies exposure. learning of new movement patterns by observation and imitation, so predominant in early life, remains a lifelong faculty and an essential component of conscious effort in the learning process. The planned learning of a new movement pattern, however, is a very definite voluntary effort involving a good deal of cerebration in the early stages, such as inspection, analysis, comparison with known movement, and evaluation (39). Descrip-

in part

The

tions of

movement

involving motor

patterns are legion.

skills,

They

and most of them

exist for almost all professions

limit

themselves

to the sequential

THE ROLE OF THE NERVOUS SYSTEM

IN

MOVEMENT

169

steps of movement. Following the directions and illustrations of a movement, the early attempts to perform it are usually awkward and clumsy — perhaps partially because the description of the movement is imprecise or because the movement is difficult or completely alien to past experiences. With repeated practice and full use of the pertinent feedback mechanisms, progress toward a smoothly performed task is made until, with time, it becomes so habitual and automatic that the performer feels little or no need for conscious effort. Probably the most important ingredient in the motor learning process is goal orientation (30, 56). Goal orientation makes learning more meaningful. It stimulates the imagination and is the only volitional input deserving superior rank and performance. Possibly one of the greatest handicaps to efficient motor learning is a persistent overemphasis on particular volitional muscular efforts in the performance of a movement or movement pattern. It becomes a double handicap when it is an integral part of a teaching philosophy. Telling a student which muscles to tighten in order to perform a movement, how parts of the body, especially the shoulders, should be held, or giving the student the idea that he should be tight and hard all over, are probably the most serious interferences imaginable with efficient function of the nervous system. Such a philosophy, found all too often in teaching the dance, fails to take into consideration the importance of an adequate concept of movement; that is what is the movement to be performed, not how is it to be performed. The nervous system takes care of the "how" of movement in accordance with a clear concept and mental picture of movement —

the process

is

ideokinetic.

The muscular components

of a

movement

or

movement

pattern can

neither be determined nor their action directed in the learning process;

movement must proceed on

its journey freely as dictated by subcortical nervous mechanisms. There can be cortical interference with the automatic flow of movement at any time, and sometimes this interference is

necessary. For example,

when

a person recognizes from proprioceptor

reports that something is wrong with the pattern or series of patterns of movement, he must change or redirect his goal. But cognitive interference

with muscle action by imposing voluntary control on it is to be avoided. Such a procedure tends to interfere with the automatic operations which proceed in accord with the innumerable sensory reports which alert the nervous system to the changes needed in the patterning of neuromuscular coordination as movement proceeds. You can set a goal for movement; you can voluntarily start and stop movement; you can speed it up, slow it down, or change its force and direction; and, finally, you can voluntarily imagine or visualize it — but here your control ends. To illustrate the ideokinetic power of imagination on subcortical planning of muscle action, visualize yourself growing tall and, in so doing.

170

THE NEUROMUSCULAR PRODUCTION OF MOVEMENT

you forcefully stretch up to make youryour body taut and unyielding. In the self taller, however, you former procedure, your muscles responded to subcortical directions, without interference of conditioned neuromuscular reflexes which may be inefficient. In the latter case, your consciously directed movement used stand upright with greater ease.

If

will find

which eliminated to a marked degree the possible influence of subcortical planning. Another example of subcortical patterning of muscle action to implement an action being imagined is to visualize the pelvis as a bowl of water which, while walking, established neuromuscular habit patterns

remain level so that water does not splash out. As walking proceeds bowl remaining level, the subcortical patterning and repatterning of muscle action in accord with sensory feedback proceeds without consciously controlled interference with the synergy of walking. With practice, one's movement in walking can become a smooth, seemingly effortless, fluid motion with minimal noise and jarring of the body as the feet contact the ground (Chapter 21). This chapter briefly has discussed in a somewhat elementary fashion the most pertinent facts about the structure, components, and functions of the nervous system in relation to movement. As important as these items are for understanding the nervous system, their importance pales in comparison with the understanding of the basic requirements of optimal nervous system performance. In general, the teacher must understand the structural components of movement and have the ability to build clear concepts of movement patterns. He must then be able to locate and to identify accurately deviations or faults in movement performance. Following this identification comes the most difficult, yet the most crucial part in successful teaching. He must be able to give cues which challenge is

to

automatically, with concentration on the

the imagination so that

it

will influence subcortical planning to eliminate

the deviants from efficient performance and oriented.

make

it

completely goal-

Part

THREE

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Patterns of Skeletal

Alignment

16 Posture: Skeletal Alignment

in

the Standing Position

may have as many postures assume positions of the body. The one posture that we shall consider is that which is unique to man: the upright posture. The upright posture is the consistent and persistent alignment of the skeletal structure in relation to the line of gravity when the subject assumes an easy standing

In the broad definition of posture, any person as he can

position with the weight evenly distributed

— according

to his or her

own

judgment — on the feet, with the ankles in the sagittal plane of the femoral joints and with the arms hanging freely at the sides.

The reasons

for considering posture in the standing position are the

following: 1.

Historically, experimental studies of posture refer to the

the upright position, even though they often differ on

how

to

body in assume

or maintain that position. 2.

It is

the position in which joints (unlike

some

of those of the quad-

ruped) can approach a neutral position for support of the body weight in equilibrium; that first-class,

3.

It is

is, it is

the position of mechanical balance of the

weight-supporting bony levers.

the position in which, in early

life,

equilibrium must be attained

before innumerable activities can be learned and pursued. 4

It is

the prevalent position in which

man moves and

carries

on many

of his daily activities. 5.

The basic neuromuscular habits of coordination developed to maintain equihbrium in the standing position influence all body positions

and movements. Posture

The foundation

is

thus the substrate of movement.

alignment of the adult in the standing Well before he is two years old, the child can usually sit, stand, and walk — all of which require coordinated muscle work. He has developed patterns of neuromuscular coordination which may be considered basic to further learning of movement. Before he is ten. position

is

for postural

laid in early

life.

173

PATTERNS OF SKELETAL ALIGNMENT

174

his basic pattern of

body alignment

pelvis) in the upright position

lumbar spine and

apparent.

accompanying neuromuscular habits (posboth primary and conditioned) can be modified by many

Thereafter, posture and ture reflexes,

is

(especially of the

its

influences: mechanics, as furniture, clothing, toys; pathology, as disease

or sickness of any kind; injury, with parts of the body; nutrition, with

ment; sociology, with society;

its

discipline, or its

its

its

protective adjustments to injured

general effects on growth and develop-

behavioral adjustments to other lack,

with

its

effects

members

on emotional

of

stability;

and, finally, psychological effects, which include imitation of elders and the accumulation and bodily expression of

many

ideas and notions, true

or false, in regard to the carriage and use of the body. Indeed, almost

all

aspects of Hfe influence the development of one's body alignment and

movement (9,82,

83).

is characterized by habit patterns of neuromuscular coordination which dominate, in all voluntary movements, the subcortical planning of the fast-changing neuromuscular coordination to realize one's goals in body positions and movement. Any attempt to study posture in terms of muscles and the external appearance of contours of the body, however, will result in a concept which cannot be supported by biological and mechanical principles. Posture is primarily an engineering study. It must be considered basically in terms of the design of the skeletal framework and its alignment to conform as closely as possible to mechanical principles of balance. The patterns of basic neuromuscular coordination related to posture will be those needed to maintain the upright equilibrium.

Posture at any age, then,

To

build a concept of an efficient upright skeletal alignment,

consider: (1) the large

number

we must

of bones which, with their articulations

and ligamentous connections, form the weight-supporting framework; the variations in bone size and design, and how these bear on the solution of the alignment problem and movement; and (3) the fact that few articulations of the many bones coincide with the line of gravity. A passive mechanical balance of the skeletal framework is impossible; the force of muscles is needed to maintain its equilibrium. Thus, posture in the standing position is a dynamic phenomenon in which the amount and extent of muscle work, and the wear and tear on the skeletal framework and its joints and ligaments, depend largely on the efficiency of the neuromuscular coordination engaged habitually in maintaining upright

(2)

balance (83).

Location of Skeletal Parts

in

Relation to the Line of Gravity

lie in the same and are equidistant from the median sagittal plane, which passes through the center of the sacral table and through the center of

In ideal posture the corresponding lateral skeletal parts

horizontal plane

POSTURE: SKELETAL ALIGNMENT gravity.

Such agreement

is

IN

THE STANDING POSITION

175

not found for the anteroposterior distribution

of the skeletal structure.

The because

ideal it is

anteroposterior alignment should be

somewhat

flexible,

doubtful that any person would ever completely conform to

it at all levels of bony articulations from head to foot. Using a coronal plane which coincides with the line of gravity as a reference, some part

of the following skeletal structures will lie in this plane: (1) the atlantooccipital joint

and the center of the

cervical vertebrae,

(3)

ears, (2) the bodies of the central

the acromial processes of the

shoulder girdle,

bodies of the central lumbar vertebrae, (5) the femoral heads, the knees, and (7) the tibiotarsal (ankle) joints (78, p. 39). (6)

(4) the

Reliability of the Posture Pattern

The

reliability of

the posture pattern in relation to the line of gravity

an indication of the extent to which the alignment and relationship of parts of the body remain the same at different levels of the body over a period of time. This phenomenon has been repeatedly demonstrated experimentally (22, 43, 63, 80). The tendency of the body to sway while standing (40, 41, 50) influences the degree of similarity of the deviations which enter into the design or pattern of alignment. Indeed, the greatest change in similarity tends to be among those parts most distant from the center of gravity. The author has found that, barring disabling accident or illness, the skeletal framework may change in the degree of its deviations as the body sways, but never in their direction — indicating the pattern of upright alignment to be most persistent (80). For example, when a subject's pelvis is more prominent laterally to one side than to the other, this prominence persists as long as the weight is on both feet; the degree of promis

inence, however, changes with body sway. In the author's study of skeletal alignment from the base of the head through the great trochanters of the femora in 497 subjects in the standing

position (80), the greatest reliability of the postural pattern in relation

through the center-top of the sacrum was shown for the central skeletal parts: the pelvis, lumbar spine, and proximal femora (r ==0.71-0.78). The decrease in reliability of deviations of any skeletal

to a vertical line

few exceptions, was proportionate to their increase in distance from the sacral table. The exceptions occurred in the upper thoracic vertebrae, where greater stability of position may be related to the function of the upper extremities, the shoulder girdle, and arms. Studies by Huelster (43) and DuBois (22), ^ who measured deviations of body contour from a vertical axis passing through the center of the parts, with a

sacral table in

young women and men,

revealed similar patterns of '

respectively, in the standing position

reliability.

DuBois' study revealed a method of determining the location of the center-top of the sacral

table from bilateral

measurements

of

body contour.

PATTERNS OF SKELETAL ALIGNMENT

176

Structural Design

The

author's concept of posture

is

based on the premise that skeletal

the key element of the upright posture pattern.

With this premmind, the following factors will be considered: (1) the design of the many skeletal parts, where and how they are joined together; (2) the primary function of these skeletal parts in weight support and movement; and (3) the laws of the lever and the principles of mechanical balance applicable to the standing position of the skeleton as a structural framestructure

is

ise in

work. Since the weight-supporting bones of the body are Class

from foot

to

I

levers stacked

head, their balance depends on the centering of weight through

is, with their force arms balancing each other. But there are other bony levers, mainly of Class III, which are also a part of the skeletal framework. To determine the alignment which will most closely conform with principles of mechanical balance, we must include these levers and consider the design of the structure as a whole. The structural framework presents the following general arrangement. There are three major, structurally unique units or masses of weight — the head, rib-case, and pelvis — which are joined together by a column of 24 movable bones (see Figure 61). Principles of mechanical balance indicate that when the three units are aligned ideally the axis of each, if extended up or down, will coincide with the axis of the other two units in the line of gravity. The rib-case and pelvis will form an integrated cylinder; the head will be centered above the cylinder. The alignment of the three units of weight and that of the spinal column are interdependent; the balance of each influences the balance of all other parts. The trunk provides attachment for the upper and lower appendages. Those above attach to the front of the top of the rib-case; those below attach to the pelvis — both to give it and all upper structure support and to move such structures about.

their fulcrums (joints), that

The Head

The head resembles inferior maxillary bone.

a round ball with only one truly mobile part, the Being the uppermost structure, it does not support

superimposed body weight, but it does aid in the support of structures below it. It gives this support "below" via muscles whose insertions are on lower skeletal parts, the shoulder girdle or ribs, which are mainly hanging structures (see p. 96). Logically, the head should be supported at the center of its base. Here we find two rockerlike projections, the occipital condyles, which rest in the cradles on either side of the top of the atlas, the first vertebra of the spinal column (see Figure 14). The head is a Class I bony lever, which moves mainly forward and backward, through flexion and extension on the atlas. Since the spinal column supports the head, it

POSTURE: SKELETAL ALIGNMENT

IN

THE STANDING POSITION

CENTRAL A.

'

177

CENTRAL

VERTICAL

VERTICAL

AXIS

AXIS

Figure 61. Schematic drawings of weight distribution of the three structural units. (A) Side view. (B) Front or back view.

is

readily seen that the balance

and location of the head

in relation to the

trunk depends entirely on the efficiency of alignment of the spinal column (85).

The Rib-Case or Thorax

The thorax

is

sometimes called the rib-case or rib-cage,

similar to a cage except in

weight

it

its

manner

of support.

for

it is,

Of the three

has the most bones, 37 in number: 24 circular

ribs,

indeed, units of

12 vertebrae,

and the breast bone or sternum, all of which articulate with each other in approximately 100 places to form a functional unit (See Chapter 11). Because of its many mobile joints, and because the ribs themselves form

bony arches completed at the front by pliable hyaline cartilage, the rib-case should ideally be freely movable in respiration, flexible for movement, and capable of absorbing shocks from direct blows, provided the impact is not too sudden and too strong. The twelve thoracic vertebrae, forming a slight curve with their convexity to the back, are located back of the central axis of the rib-case (see Chapter 6). They support most of the weight of the circling ribs and flexible

PATTERNS OF SKELETAL ALIGNMENT

178

the breast bone to which the ribs are attached at the front.

The

ribs ex-

tend from their vertebral attachments diagonally backward and downward as far as their angles. There they turn to circle to the front. Their angles are

approximately in vertical alignment forming a backward curve which corresponds to that formed by the spinous processes of the thoracic ver-

Thus some

tebrae.

and weight of the rib-case is back of ribs and breast bone, as hanging are given further support by muscles which connect them either of the structure

the supporting thoracic vertebrae. structures,

The

to higher levels of the ribs or the thoracic spine, or to the cervical spine

and base

of the head.

The alignment on

of the rib-case relative to the

head and

pelvis

depends

(1) the alignment of the supporting spine, and (2) the tension of attached

muscles which have origin at higher or more central skeletal parts. To conform to the principles of mechanical balance, all parts of the rib-case should be as close to the central line and as close to the pelvic base as the structure allows.

Even the continued movement

of the ribs

and breast bone

with the alignment of the spine; it steadied against their movement by subcortical planning of muscle action.

in respiration does not interfere

In the majority of people the rib-case

is

not as mobile as

its

many

is

joints

from the persistent — and erroneous — notion that the chest must be "lifted" or "held up" if the posture is to be "good." Practice of this idea, along with the common habit of allow. This loss of mobility results, in part,

lifting

the chest

when

taking a "readiness-for-action" position, as in the

dance, gymnastics, and various other

activities, results in

undue

tightness

muscles which lift the ribs. As a result, the trunk is elongated in and shortened in back. This type of tight rib-case is found not only in a majority of those persons engaged in strenuous activity, but also in much of the adult population. In later life it may be accompanied by an increase of the backward curve in the upper thoracic (dowager's hump) area, and it in those

front

often leads to backache.

The Pelvis

The pelvis is the base of the trunk, the area where all weight of the superincumbent structure converges. Thus it is the area of greatest importance for structural balance (see Chapter 5). The center of gravity lies within the pelvis in front of the upper part of the sacrum. To enable it to perform its strategic role in both balance and movement, nature has equipped the pelvis with large bones, numerous strong ligaments, and large powerful muscles. The pelvis is made up of just three bones whose articulations are only slightly movable. These bones are so strongly bound together by ligaments that there can be only very slight independence of movement of one side of the pelvis in relation to the other side. The pelvis resembles a bottomless bowl, tipped downward

POSTURE: SKELETAL ALIGNMENT

with no

IN

THE STANDING POSITION

179

base to rest on. In the standing position, the bases of contact of the pelvis with a supporting structure are at the femoral sockets on the rounded heads of the femora. In sitting, weight is supported

in front, but

on

its

flat

rockerlike ischial tuberosities. Both of the supporting surfaces are

rounded, assuring greater mobility than stability. Weight is transferred from above into the pelvis at the area of greatest thickness of the upper part of its rim at the back. From there it is transferred outward, forward, and

downward,

to the acetabulae in standing, or

most direct line from the upper sacrum. This curved line of weight transfer presents the greatest bony thickness of the pelvic rim. Thus the weight transfers from a higher level at the back of the pelvis to a lower level farther to the front, and the downward slope of the pathway on either side of the pelvis is determined by its anteroposterior tilt. The downward pressure at the center back of the pelvic rim is balanced by the anchorage of its front part to the femoral heads by the ileofemoral or Y ligaments. Probably no factor influences the proper anteroposterior tilt of the pelvis more than the type of sacrum an individual inherits. It may be relatively straight, moderately curved, or markedly curved. The degree of its curve determines the slant of the sacral table at the center of its uppermost surface. This sacral table is the base of support of the spine, and therefore it marks the change of the forward curve of the lumbar spine to the backward curve of the sacrum. It can never be level. Only at the center of the anteroposterior spinal curves can any supporting surface of the vertebral bodies approximate a level position. The slant of the sacral table, therefore, determines both the anteroposterior tilt of the pelvis and the depth of the anteroposterior curves of the spine which will give them their most efficient balance for weight support and the greatest flexibility for movement. Because of the roundness of the femoral heads which support the pelvis to the ischial tuberosities in sitting, along the

at the acetabular sockets, all

movement

of the pelvis

is

that of rotation,

on the femoral heads. Any persistent rotation of the pelvis which appears each time a person assumes the standing position will directly affect (1) the efficiency of the position of the sacral table for support of its superimposed weight, and hence the alignment of this weight for balance; and (2) the relative distance of the thighs from the sacral table and from the line of gravity. The limb that is farthest from the line of gravity of the trunk will require more muscular work to carry on its activities, and adjustment of some type in this limb must be made at the knee and ankle joints in the pursuit of

which can be only

slightly different in its lateral halves,

their functions. Thus, the position of the pelvis in relation to the line of

gravity influences both the alignment of

the accompanying pattern of muscle skeletal equilibrium.

all

the skeletal framework and

work which

strives to

maintain the

PATTERNS OF SKELETAL ALIGNMENT

180

The Spinal Column

As stated above, the spinal column joins the head, thorax, and pelvis and thus plays an important part in the alignment of these structural units. It is unfortunate that we refer to the spinal column as the "backbone," because this word suggests rigidity and detracts from the idea of the space

A well-balanced spine is never rigid, bone, it tends to extend forward past the "back" and contrary to being a center of the trunk in its cervical and lumbar regions in order to give adequate support to the weight it carries. There is much more to the spinal column than is evidenced on the surface of the back. The spinal column, as described in Chapter 6, is a sturdy but flexible the spine occupies within the trunk.

column

of

24 mobile vertebrae whose primary function is

to

support weight.

movement. To provide maximal mechanical advantage for weight support by a flexible column, the spine develops two forward curves to center under the weight it must support in the upright Its

secondary function

position.

From

is

top to bottom, the

seven cervical vertebrae curve

first

convexly toward the front, the next twelve thoracic vertebrae retain their original curve present at birth, with

the

last five

its

convexity to the back, and

lumbar vertebrae curve once more convexly toward the front. series of fused vertebrae which form the back of the pelvis,

The sacrum, a retains

its

original curve with

its

convexity to the back.

The only approx-

imately level places for weight support, as previously stated, occur at the center of each curve;

on

all

other vertebrae are

their location within the curves.

flexible spinal

make it level,

To

column and the sacrum

more

or less slanted, depending

reiterate, then, the junction of the is

at a slant.

Any

attempt to with the balance

willful

as with "pelvis tucking," seriously interferes

of the curves of the spinal column, as well as with the balance of the pelvis.

Such interference can occur

also

with any voluntary efforts to

increase the postural function of the psoas major muscles, which help to

govern the relationship of the lumbar spine and proximal femora. In trying to determine the ideal alignment of the spinal column, remember that the depth of the anteroposterior curves appears to be much less on the outside of the trunk than on the inside. This illusion results from the difference in size and slant of the spinous processes, which reduce the

appearance of the depth of the curves to just a slight, pleasing undulation on the surface of the back. To give the spine added stability for supporting weight, it is reinforced by numerous ligaments, some of which run the entire length of the bodies of the vertebrae. Ideally, the anteroposterior curves of the spine should lie in the sagittal

area.

Only when the vertebrae are in machanical balance as Class I levers be fully flexible to perform its secondary function of move-

will the spine

ment.

median

plane of the trunk without any persistent lateral deviation in any

POSTURE: SKELETAL ALIGNMENT IN THE STANDING POSITION

181

The Upper Extremities

As we discussed in Chapter 10, the upper extremities consist of the shoulder girdle (scapula with clavical on either side) and an arm hanging from each scapula. The shoulder girdle is a structure superimposed over the top of the rib-case. its

No

weight of the body

on the shoulder

rests

only role in weight support in the upright position

the hanging arms. in back, nor

The girdle

do they attach

is

to

girdle;

that of supporting

is

incomplete in that the scapulae do not meet any part of the back of the rib-case. The

incompleteness of the girdle makes

it

possible for one side of the upper

extremities to be quite independent of the other side.

The only

points of articulation of the shoulder girdle with the skeleton

are on the front on either side of the top of the sternum and the cartilage of the first rib at the sternoclavicular joints. articular fibrocartilage allow

movement

These

joints

girdle belongs to the upper-front of the rib-case.

It is,

with their

inter-

Thus the shoulder

in all directions.

in part, a

hanging

which is supported intermittently by some of the muscles which attach it to bones at a higher level, that is, to the cervical spine and to the head. Both the relative tension of these muscles and the alignment of structure,

the underlying supporting skeletal structures strongly influence the position of the shoulder girdle in relation to the line of gravity

and

to the pelvic

(1)

the shoulder

base.

The upper

extremities are efficiently aligned

when

and arms hang free without restriction of any pattern of tightness the muscles connecting the arms to the scapulae, or the shoulder girdle the trunk and head; (2) the shoulder girdle as a structural weight is close to the pelvic base and to the line of gravity as possible; (3) the

girdle of to

as

is, without movement any direction; (4) the shoulder blades are of even height and lie close to the ribs with their inner borders in line with the angles of the ribs, and without projection of their inferior angles; (5) the muscles which give some support from above provide only enough tension to counteract the changing pull of gravity as the body sways in the standing position; and (6) there is no undue muscle tightness between the shoulder blades and

sternoclavicular joints are in neutral position, that in

spine,

and

between the humerus and shoulder

girdle, or

between the humerus

pelvis.

No amount of voluntary effort will help postural alignment.

of a leaning building over

to "hold" the shoulders in a fixed position

Such an action

its

is

as absurd as pulling the roof

foundation without aligning

its

supporting

beams.

The Lower Extremities

movement, as in the majority of activities, the lower extremities both support and move the body weight while the upper In everyday

PATTERNS OF SKELETAL ALIGNMENT

182

The

extremities only move.

difference in design of these

appended

parts

provides adequately for their difference in function (Chapters 7 and 10). In contrast to the shoulder girdle, the structure of the pelvic girdle, to

which the

low^er

Hmbs

are attached, lends itself to the support of body

weight. Unlike the incomplete shoulder girdle,

and the

articulations of

it

forms a complete

circle

three large bones with each other allow very

its

movement between its right and left sides. This any movement of the pelvis which accompanies that of either or both lower limbs to increase their range of movement must be made by the pelvis moving mainly as a whole. Such movement, however, may be restricted by the iliofemoral or Y Hgament when one limb supports the body while the other moves. The greatest evidence of this ligamentous restriction occurs in movements of force and relatively large range, such as punting a football or performing the grand battement en avant in dancing (see Figure 25); it occurs to a lesser degree in the movement slight differences in

means

that

of the pelvis during the relatively simple act of walking.

As

in

any structure which must support weight, the more nearly the

supporting beams (the lower extremities in the standing position) are

more

aligned, the

efficiently they will function in

and movement, when movement is

centered at the femoral

joints,

is

both weight support

a part of function. Ideally,

the long axes of the lower limbs are in a

vertical position in the coronal plane of the line of gravity is

directed forward so that

it

centers of the femoral, knee, extremities, however,

is

is

Rarely,

if

ever,

do

when such alignment

we

and each

foot

bisected by a sagittal plane through the

and ankle

influenced to a

rotation of the pelvis, especially

when weight

its

joints. The position of the lower marked extent by any persistent

anteroposterior

tilt

as described above.

find ideal alignment of the lower Hmbs.

Even

approached, the sway of the body in standing

is

requires the intermittent action of muscles, especially in the lower limbs, to retain equilibrium of the

body

as a whole. Experience in the posture

laboratory, however, indicates that

body sway becomes

less

pronounced

(but not necessarily less frequent) as postural alignment improves.

The two minimal

essentials for efficient function of the lower extremities with

stress in joints

and ligaments are

(1) the centering of

weight

at

the femoral joints, and (2) primary muscular control of their movement close to the pelvis, which is comparable to the application of power to the exists

handle of a whip or a fishing pole. Only when this type of control can the two-joint muscles, especially the hamstrings, be supple

enough to the

to transfer the

movement

power

of the

of one-joint muscles at the pelvis efficiently

most

distal joints.

Failure to

meet these two

knees and feet, especially among dancers and athletes. In short, problems of the knees and feet, as a rule, begin in the area of the pelvis and proximal femora. essentials often causes injury to the

POSTURE: SKELETAL ALIGNMENT

Skeletal

IN

THE STANDING POSITION

183

Alignment and Related Muscular Activity

As stated above, ideal postural alignment of the human body in the is one in which the alignment of the structural framework as a whole approaches conformity with the principles of mechanical standing position

balance, as closely as

its

structural

however, no alignment of the

design will

human

skeleton with

varied in size and design, can position (78).

to

it

Unfortunately,

allow. its

many

bones, so

upright in mechanical balance

The body needs muscle power and/or ligamentous support

maintain

its

at joints

upright equilibrium. In ideal alignment muscles around

movement

any

approach balance in their tonus. In general, the deeper and smaller muscles which attach directly to the weight-supporting bones work to maintain upright equilibrium, while the larger, stronger, and more superficial muscles remain relatively free to produce desired movement or to help to maintain equilibrium when the body sways off balance too far for recovery by the deep muscles. The muscles which help to maintain equilibrium need not work constantly; they become active intermittently in the location and to the degree that balance is threatened by gravitational and other forces. There is a good possibility that, ideally, much of this muscle work is performed by the intrafusal fibers of the muscle spindles (see Chapter 15).

joints, or

dealing with the

''Anti-Gravity'' It

of

joint,

Muscles

has been assumed that the extensor muscles, often designated as

must be strong to maintain an upright posture, and that lack of strength in these muscles contributes significantly to poor posture. This is a debatable concept, as indicated by electromyographic studies (50). The extensors must be strong to return the body to the upright position from the great variety of positions it assumes during the course of the day. Once the body is upright, however, strength is no longer the key factor in maintaining equilibrium. Any muscle or group of muscles becomes "anti-gravity" depending on the direction in which the body deviates from alignment or sways toward imbalance.

"anti-gravity" muscles,

Fatigue in Standing It

would seem

many people

that the standing position should not

be

fatiguing, yet

"Standing fatigue" results from circulatory inadequacies, undue stress in soft tissues, and frequent and continued pressure of tight muscles on veins of the lower limbs, especially if poor alignment for

it

is.

On the other hand, the person who has an exceptionally and dynamic (responsive to gravitational changes) posture expends minimal muscular energy with minimal sagging against ligaments and only intermittent pressure on veins. Such a person may stand relatively long is

persistent.

efficient

PATTERNS OF SKELETAL ALIGNMENT

184

periods of time, with small but frequent body sway, without shifting from

one distorted alignment to another. With good posture the task of weight support is performed mainly by the skeletal framework; and the small, frequent sway aids circulation and distributes muscle work. Hence standing becomes less fatiguing. Influence of Postural Deviations on

Body

Position

and Movement The two from

conditions most

efficient skeletal

commonly found with

alignment are

(hypertonicity) of those muscles

(1)

persistent deviations

disproportionate development

which are most frequently and continu-

ously engaged in maintaining equilibrium in the upright position, and (2)

deformation (mechanical strain) in bones and cartilage resulting from

the harmful stresses which occur with persistent and similar unevenness of the pressure of weight.

These two conditions can lead

to

decreased

ease and range of movement, and to increased wear and tear on the

framework. Hypertonic Muscles. As noted in Chapter 4, all bones supporting superimposed weight are Class I levers, and when weight is centered through the fulcrum of each (the joint), they are in mechanical balance. skeletal

When

any of these levers persistently deviate in some direction from a balanced position, however, extra muscle work must be added to one of the lever arms to maintain

its stability.

Thus

in poor skeletal alignment

the imbalance of weight-supporting bony levers results in an uneven

work load, both in frequency and quantity, on those muscles and ligaments which are most persistently involved in maintaining upright equilibrium. The location of this muscle work and ligamentous support depends on the location and direction of the deviations of the Class I levers from mechanical balance. The amount of muscle work needed depends upon the degree of imbalance of the levers and the amount of distribution of

weight the poorly balanced levers support. The net result is a pattern of relatively unbalanced muscle development which correlates with the pattern of deviations from efficient skeletal alignment.

The is

correlation

between hypertonic muscles and

so reliable that the author has found that

an x-ray photograph, preferably one taken

it is

skeletal deviations

possible to predict from

in the standing position, the

location of hypertonic muscles necessary to hold the structure in balance. it is possible to determine the pattern of hypertonic muscles by palpation, and then to predict from it fairly accurately the location and degree of the underlying skeletal deviations. Some muscles may also become hypertonic through persistent use in carrying out a person's beliefs in what "good" posture ought to be and how it ought to be secured. These muscles mainly move Class III bony levers. They are called into use by the person who thinks that a good posture can

Likewise,

POSTURE: SKELETAL ALIGNMENT

THE STANDING POSITION

IN

185

be assumed voluntarily by fixing and holding parts of the body in the specific relationships which conform to underlying beliefs. Generally the head is

held "up and back," the chest "up," the shoulders "back, down, and

even," the pelvis "up" in front and "down" in back, and the abdominal

muscles "in" and "taut."

neck and shoulders, may be-

Finally, muscles, especially those of the

come hypertonic through

their persistent

involvement in mental and emo-

tional strain.

To understand the influence of hypertonic muscles on body positions and movement, remember that, as a rule, muscles precede ligaments and joint design in restricting the range of movement. Hypertonic muscles are less supple (lengthen less easily) and hence interfere with the free operation of the law of reciprocal innervation. As the range of movement increases, the hypertonic muscles, as antagonists to the movement, resist lengthening in proportion to the contraction of the agonists of the movement. Thus they restrict the range of movement too quickly, and the agonists which are contracting to produce the movement must work harder to overcome the restriction, if indeed they can completely do so. In assuming various positions of the body, the hypertonic muscles often limit the joint action

This

is

needed

to place the parts of the

particularly noticeable in the

well as in the sitting position of

deep

many

on the

plie of

in the position desired.

some male dancers

as

people.

Two positions of the body which readily flexibility of

body

reveal the location of decreased

weight-supporting joints are the "fold-up" position, and sitting

with the legs to one side (see Chapter 23). Bone and cartilage deformation (mechanical strain). The internal arrangement of bone cells changes in response to any continued deviation of weight pressure from that which is normal in mechanical balance. Likewise, cartilage in the joints responds to consistent unevenness of weight floor

pressure by losing some or

all of the elasticity which enables it to return normal form when pressure is removed (76). Bone and cartilage deformation may be caused by congenital anomaly, accident, disease, or mechanical strain. When caused by mechanical strain, the deformations are detected in the spinal column sooner and more often than in any other part of the skeletal framework. They are revealed in (1) lateral deviation or lateral curve, which results in a difference in the lateral height of the bodies of the vertebrae and their discs; (2) exaggeration of any parts of the natural anteroposterior curves, resulting in a decrease in the depth of the vertebrae and discs on the concave side of the curve (often noticeable in the upper thoracic spine as the "dowager's hump"); and (3) "pelvis tucking," which decreases the forward curve of the lumbar

to

spine and results in a decrease of the front depth of the vertebrae and their discs.

Spinal deformation can restrict normal

movement, depending on the

PATTERNS OF SKELETAL ALIGNMENT

186

location

and degree of persistent deviations from

efficient alignment.

Ex-

perience in the posture laboratory indicates that, even with improved bal-

ance of the spine, deformation of the vertebral bodies and their intervening with its effects on alignment and movement, can never be completely overcome. The alignment of the spinal column is of greater import for both good appearance and freedom from muscular pain and strain, especially in the low back, than that of any other part of the skeletal framework. Bone deformation occurs also with knock-knees and some bow legs. Both interfere with the centering of weight at the knee and ankle joints, discs,

and hence with the flexibility of these joints. Dancers do whatever they can with voluntary muscle work to minimize either condition and its effect on foot positions. In case of knock-knees, first position of the feet is impossible without some crossing of the knees; with bow legs, when the feet are in first position, the knees are too far apart. With the increase of neuromuscular efficiency effected by ideation (imagined movement), as described in Chapter 20, some improvement in appearance can be made; but the restrictive effects of both on the alignment and flexibility of the knees and ankles can never be completely eHminated unless the legs only appeared to be bowed because of overdevelopment of muscles of the thighs and legs. In summary, a viable concept of efficient postural alignment must be based on the design of the skeletal framework, the main function of its various parts (whether for weight support, for movement, or for both), and, finally, on the principles of mechanical balance. These principles must govern the alignment of a structural framework to reduce harmful its efficiency and greater durability. no standard norm either for efficient skeletal alignment or for the surface contour of the body. Moreover, the concept of ideal posture probably will never fit any one person because of the obvious differences among people, both in inherent structure and in body conformation. The teacher's ideal, therefore, must remain flexible and must adjust to each

stresses and, thus, to contribute to

There

is

individual. Nevertheless, tion

and

it

should serve as a constant guide in the detec-

identification of postural deviations.

The concept

of

an

efficient posture

must be developed through learning

the facts of structure and principles of mechanics, through eradicating all beliefs about posture and movement that have no basis in fact, and through the experience of improving one's own posture, such improvement being manifested primarily in a more pleasing figure, increased flexibility,

and greater bodily comfort.

17 Skeletal Deviations Identified in

Postural Alignment

The

and solving problems of musand limitation in range of movement is based primarily on the results of two of her experimental studies. These studies dealt with (1) the changes in skeletal alignment in 200 subjects who had posture teaching by the author for one semester, and (2) the statistical analysis of bilateral deviations from symmetrical alignment as found in the x-ray photographs of the skeletal framework of 497 subjects in the standing position. author's procedure for teaching posture

cular pain, strain,

Changes

in Skeletal

Alignment with Posture Teaching

This study, done from 1929 through 1931, was the first attempt to determine whether ideokinesis, as defined below, could recoordinate muscle action enough to produce measurable changes in skeletal alignment. The study is of historical significance in that it supplied the basis for both the author's subsequent research on bilateral skeletal deviations, and her procedure in teaching body balance and movement, as presented in this text.

The purposes 1.

of this unpublished study were:

To determine whether measurable changes

in the relationship

and

alignment of skeletal parts in the standing position could be attained through ideokinesis, that is, through repeated ideation of a move2.

3.

ment without volitional physical effort. To determine, if changes occurred, whether there were any which were similar in direction and location in the majority of subjects. To determine whether these changes could serve as a basis for developing an organization for imagined movement, both as to its location and direction, that would have general application in procedures for improvement of posture and movement. 187

PATTERNS OF SKELETAL ALIGNMENT

188

In undertaking this study

it

was hypothesized

that (1) specific habit

patterns of neuromuscular coordination develop with each person's skeletal alignment to maintain its equilibrium in the upright position, (2) change in these habits would be accompanied by a change in skeletal alignment, and (3) imagined movement could act as the ideokinetic facilitator. The study involved 200 adult female students ranging from 20 to 50

years old. a

common

They were

of diverse professional backgrounds, but

interest in improving their postural alignment.

a subject for

No

all

shared

student was

more than one semester. They met weekly in 30 -minute

classes

of six to eight students for a semester of 15 weeks.

Teaching Procedure

Each subject was taught to concentrate on visualizing movement of body to place them in an alignment which was considered good by traditional standards (53). Any physical effort to assist the movement being visualized was called to the attention of the student until she learned to eliminate all physical effort and concentrate only on "watching" movement in her body. When a subject wished to perform some voluntary act which she had been led to believe would improve her posture, she was told to imagine it only. For example, in the case of balancing a book on top the head while walking, the advice given was to imagine the book balancing on the head as the subject walked naturally at her regular gait, and without "holding" the head or trunk for steady support of the imagined various parts of the

book.

The imagined movement taught to the group sometimes dealt with the movement of bones themselves, or with movement in some mechanical gadget representing some part of the structure — for example, the rib-case as a toy accordion being closed inside the shoulder girdle, or the pelvis

bowl moving up in front to a level position (see Chapters 20 and 21). and many different bones, toys, and pictures were all used to aid the student in locating, in her imagination, definite parts of her body and to give her an understanding of the movement to be visualized. The teacher's hands were used to help the student sense the location of specific parts of the body, to indicate the direction of imagined movement in the area, and to help her recognize the sensory reports which accompanied change in neuromuscular coordination in response to concentration on imagined movement. The procedure taught in the posture laboratory was practiced daily by the subjects in various positions, in standing, and in walking. Good mechanics of everyday movement were emphasized repeatedly in teaching. In using imagery concerning everyday voluntary movement, such as walking, the imagery was always located in some area of the trunk, never in the moving limbs. as a

An

entire skeleton

SKELETAL DEVIATIONS IDENTIFIED IN POSTURAL ALIGNMENT

189

Measurements Duplicate measurements of skeletal relationships and alignment (recorded by a secretary) were taken a week apart on each subject before and, similarly, after a semester of teaching. Before the measurements were taken, the subject was told to stand easily with her weight distributed evenly

on both

feet

and her arms hanging freely

at the sides.

When

she grew

unsteady, the subject was asked to take a few steps and then resume her standing position.

The Posturimeter (Figure 62), designed by the American Child Health Association, was used to determine the vertical and horizontal position of various skeletal parts. Other measuring instruments used were the stadiometer, tape line, and wooden calipers. Each surface projection of the-skeleton was measured in relation to as

many

other skeletal parts as possible, with awareness that no part of

the skeleton could be considered a fixed position for measurement. Only the vertical uprights of the "Posturimeter" and the position of the heels of the feet

ment

which

it

of horizontal

prescribed were unchanging references forTneasure-

and

vertical position of various parts of the skeleton,

such as the head, the top of the breast bone, the

first

and twelfth thoracic

vertebrae, and the pelvis.

An example

of the

number and type

of

measurements made

is

that of

the anterior part of the tip of the acromial process and the inferior angle of the scapula of each side in relation to both the anterior

superior spines of the

Figure 62.

The

ilia

Posturimeter.

on either

side,

and

and posterior

to the tip of the spinous process

190

PATTERNS OF SKELETAL ALIGNMENT

of the

first

thoracic vertebra. In this particular situation, 20

measurements

on each side determined the relationship of the top of the acromial process and the inferior angle of the scapula to the front and back of the pelvis and to the first thoracic vertebra. Thus, the difference, if any, between the 20 measurements taken in duplicate before and again after a semester of posture teaching were used to determine the direction of change in position of the shoulder blades relative to other parts of the skeletal structure. anterior

and posterior superior spines of the

ilia

were measured

The

in relation

each external malleolus. The difference in the vertical and horizontal position of the central parts of the skeleton were determined from measurements made with the Posturimeter. to

measurements of skeletal relationships, of which the measurements were also made of the circumference and of the pelvis at their largest parts, and of the standing

In addition to the

above

is illustrative,

of the rib-case

and

sitting heights of the subjects.

Analysis of Measurements

*

At the end of the two-year teaching program

all

measurements were

analyzed in the following ways: 1. is,

To determine

the degree of reliability of the measurements, that

the degree of agreement (a) between those taken in duplicate at the

beginning of the semester, and (h) between those taken in duplicate at the end of the semester of teaching. 2.

To determine

the differences,

if

any, in measurements taken at the

beginning of the semester and those taken after the period of teaching at the 3.

end of the semester.

To determine which changes

in skeletal alignment,

common to the majority of the subjects. Many of the measurements, taken a week

apart,

if

were found

any,

to

were

be highly

being exactly the same. If there was no more than % inch difference, an average was used; if there was only % inch difference, the

reliable, often

lower number was always used; otherwise the measurement was discarded

Measurement of the

and posterior sometimes as much as %, inch. Body sway probably had the greatest influence on these measurements. They were discarded as unreliable, but nothing was lost by this discard since both the horizontal and vertical changes in position of the center-front and center-back of the pelvis were determined on the posturimeter where the heels of the feet were maintained in a prescribed as unreliable.

superior spines of the

ilia

relationship of the anterior

to the malleoli varied the most,

position.

Comparison of measurements taken before and again after the semester showed that significant changes in postural alignment had oc-

of teaching

SKELETAL DEVIATIONS IDENTIFIED IN POSTURAL ALIGNMENT

191

all subjects. Some of these changes, though reliable, seemed be highly individual in that there was no consistency in their occurrence in other subjects. Other changes, however, occurred with sufficient frequency to be classified as common to a majority of, and often to all, subjects. These changes were the following:

curred in to

1.

The height both

sitting

and standing was increased, with greater

increase in the sitting than in the standing height. Probably sitting

height

was increased by lengthening

of the spine, a less forward

head, and by decreased anteroposterior height was robbed of teroposterior

tilt

some

tilt

of the pelvis. Standing

of this increase because decreased an-

of the pelvis

moved

the femoral sockets and fem-

oral heads higher in front.

The shoulder girdle moved forward and downward, approaching symmetry of position. 3 The spine increased in length from the spinous process of the first 2.

bilateral

thoracic vertebra to the 4.

The

end of the sacrum.

distance between the great trochanters of the femora

was

increased as measured across the back of the pelvis, with concomitant decrease in distance across the front. 5. 6.

The circumference of the pelvis decreased at its largest The width and circumference of the rib-case decreased

part. at the level

of the ninth rib. 7.

The mid-front of the pelvis moved forward and upward with concomitant backward and downward movement of the back of the pelvis at the

8. 9.

10. 11.

12.

most prominent part of the sacrum.

The head moved backward. The first thoracic vertebra moved backward. The twelfth thoracic vertebra moved forward. The top of the breast bone moved upward and forward. Change in the position of the pelvis resulted in an approach the lower limbs toward a vertical position; that

moved backward

is,

of

the femoral joints

in relation to the position of the ankles.

The above changes, found in almost all subjects, indicate unequivocally ahgnment through the use of imagined movement

that change in postural as

an ideokinetic technique of teaching, uncomplicated by any voluntary

holding or positioning of parts of the body,

is

feasible.

The

results indicate

that ideation (ideokinesis) is accompanied by subcortical patterning of muscle coordination, and that movement occurs in response to ideas. It was, therefore, postulated that ideokinesis is an effective means of producing measurable changes in postural alignment.

A study

of the changes indicates that, corresponding to the increase in

PATTERNS OF SKELETAL ALIGNMENT

192

height, weight masses

were

closer to both the center

hanging structures such as the ribs pelvic base; the anteroposterior

and shoulder

tilt

and Hne of gravity; were closer to the

girdle

of the pelvis as the base of support

upper structure decreased; and backward movement of the pelvis, occurring with the decrease of its anteroposterior tilt, resulted in an approach of the lower limbs toward a vertical position for their support of body weight. These changes indicate that a closer approach of skeletal alignment to conformity with principles of mechanical balance had been made; and, since voluntary effort to hold or place any part of the body in a supposedly better position constantly had been discouraged, the improvement in the mechanical functions of the skeleton in weight support and movement resulted primarily from subcortical patterning of muscle function in response to the ideation involved in the process of locating and for the

movement

imagining

in the body.

Location and Direction of Imagined

Where direction

in the skeletal structure

must

take to bring

it

its

Movement

must movement be located, and what alignment into closer conformity with

the principles of mechanical balance?

The above

findings provided in-

valuable information for the development of an organized and orderly use

movement throughout the body. Location and direction were from a study of the location and direction of movement of the skeletal parts associated with the 12 specific changes which occurred in most of the subjects; (2) from the structural design of these parts; and (3) from the significance of function of each in weight support, movement, of imagined

derived

(1)

or both.

Nine areas of the skeleton were identified

as those

whose

location

and

alignment had the greatest influence on the alignment of the structure as a whole.

The

location

and direction of imagined movement

in

each of

these areas was identified as a line-of-movement between specific skeletal

each beginning and ending in bone. Each line-of-movement resulted from the coordinated work of all muscles engaged in its production.

parts,

Two hnes-of-movement, which relate to the spine and the rib-case, promote mainly a relaxation of muscles unnecessarily engaged in weight support. All others promote recoordination of the action of muscles, especially of those attached to the weight-supporting Class

I

levers, to

make

them less dependent on muscle power to maintain their stability. It is much more difficult to recoordinate muscles than to relax them, but recoordination

is

essential

if

the thrust of weight

is

to

be centered through

joints in-

stead of continually sagging against their ligaments.

Each line-of-movement influences every other line-of-movement, and together they promote increased

neuromuscular coordination.

efficiency

in

subcortically

controlled

SKELETAL DEVIATIONS IDENTIFIED IN POSTURAL ALIGNMENT

193

Lines-of-Movement

Each

of the following lines-of-movement (see Figure 63)

is

described

changes which occurred with posture teaching; also defined are the location, direction, and purpose of each line-of-movement. 1 A line-of-movement to lengthen the spine downward. We know that the spine lengthened both by the specific spinal measurements and by

in terms of the

the increase in sitting and standing height.

and

The

anteroposterior

tilt

of the

lowered the level of support of the spine. Thus, one of the directions of movement in the spine as a whole was downward as the response to imagined movement's having released tightness in the muscles of the back, especially in the lumbar area. 2. A line-of-movement to shorten the distance between the mid-front of the pelvis and the twelfth thoracic vertebra. As a result of posture teachpelvis decreased,

in

doing so

ing, the front of the pelvis

moved upward and

moved forward, shortening ical, structural,

to

more

it

the twelfth thoracic vertebra

the distance between them. Various mechan-

and functional

factors support this

change

as contributing

efficient support of weight, as follows: (a) the relative location

of the sacral table and the femoral heads; (b) the transfer of weight forward, downward, and outward from the sacral table through the pelvis to the

® V

BACK

FRONT

Figure 63. Lines-of-movement, with location and direction of movement indicated on schematic drawings of the body.

PATTERNS OF SKELETAL ALIGNMENT

194

acetabulae and femoral heads;

on the front of the femoral

(c)

joints;

the function of the iliofemoral ligaments

and

(d) the location of the

psoas major

muscles, whose shortening can influence both the balance of the lumbar pelvis

form of a forward curve, and the position of the front of the between the lumbar spine and the proximal femora (see Chapters

5 and

7).

Of

all

spine, in the

the skeletal relationships, that of the mid-front of the pelvis to

the twelfth thoracic vertebra

most important

dom

of

is

the most difficult to achieve, yet

for balance of the central skeletal structures

movement

and

it is

the

for free-

of the lower extremities.

A

line-of-movement from the top of the sternum to the top of the spine. The changes which indicated the need for this line-of-movement 3.

were increase in the length of the spine, increase in the sitting and standing heights, backward movement of both the first thoracic vertebra and the head, and upward movement of the breast bone. These changes all have a bearing on the relation of the top of the sternum and the front part of the upper rib-case to the forward cervical curve. The change in position of the head and the first thoracic vertebra indicates also that the upper spine has assumed a better alignment in relation to the pelvis. This lineof-movement may either lengthen or decrease the distance between the upper front of the rib-case and the cervical spine, depending on previous body alignment — whether of a "military bearing" or "debutante slouch."

Two

factors strongly influence success in this line-of-movement:

(a)

the attainment of a good relative position of the pelvis and lumbar spine,

and

(b) consistent location of

sible in all

bending

in the femoral joints insofar as pos-

forward movements of the trunk, with minimal bending in the

spine. 4. A line-of-movement to narrow the rib-case. The decrease in the width and circumference of the rib-case and the lowering of the position of the shoulders indicate that less muscular effort is put forth in "holding" either the chest or shoulders in position. Even though imagined movement in the rib-case is invariably toward the central line of the body or toward the spine to which the ribs attach, the objective is not to narrow the ribcase but to promote flexibility in the rib-case as allowed by its 100 or more movable joints, and to increase the range of movement of the ribs as may be needed in breathing. Success in this line-of-movement makes a marked contribution to alignment of the spine for weight support, to flexibility of the shoulder girdle, and to a more efficient position of the pelvis and lower limbs. 5 A line-of-movement to widen across the back of the pelvis. The fact that all patterns of normal movement of the lower limbs begin at the femoral joint indicates the great importance of the stability and mobility of this joint, both for weight support and for movement. The position of the .

SKELETAL DEVIATIONS IDENTIFIED IN POSTURAL ALIGNMENT

195

heads of the femora in their sockets is as important to the efficiency of their mechanical function as the position of the hub of a wheel on its axle is to its mechanical function. When muscles across the back of the pelvis are constantly tighter than necessary, the heads of the femora cannot be centered in their sockets; and their movement, especially that of flexion,

meets strong muscular resistance. This line-of-movement helps to release the tightness of the outward

femora which so often occurs when the ribs are held upward and the anteroposterior tilt of the pelvis is too marked. It gives the pelvis a better contour in reducing its backward prominence; it does not increase the horizontal width of the pelvis — as most students postulate when first exposed to this line-of-movement. 6. A line-of-movement to narrow across the front of the pelvis. This line-of-movement improves muscle control on the inside of the thigh joints and thus contributes to the centering of weight in the femoral joints. Whereas the preceding line-of-movement released muscle tightness on the back of the pelvis, this one promotes an increase of muscle work on the inside and front of the femoral joints, which helps to prevent weight from sagging against the Y ligaments. Even though these ligaments are the strongest in rotators of the

(the lifted chest)

the body,

when

they are subjected to persistent stretching stress they will

when such stress removed. The muscles whose activity is increased by this line-of-movement are probably the psoas major, the iliacus, the pectineus, and the adductor brevis and longus on each side of the body. 7. A line-of-movement from the center of the knee to the center of the femoral joint. The change of the lower limbs toward a vertical position for support of the pelvis indicates an improved relationship of the femora to the pelvis at the femoral sockets. This change, with others in the pelvic area as indicated in the two preceding lines-of-movement, results in a better balance of each half of the pelvis as a Class I lever with the femoral joint as its fulcrum. The direction and centered location of imagined movement in the thigh is essential to promote balance of muscle action around the femur and primary control of the lower extremity close to the pelvis. Only when the lower limb is controlled close to the pelvis can it engage in its synergy of movement with minimal strain placed on the joints of the knee, ankle, and foot. Success in this line-of-movement below the pelvis is as important in promoting change of the pelvis toward a more efficient position as is success in the line-of-movement above the pelvis to narrow the rib-case. In other words, the alignment of structures above and below eventually lose their ability to return to normal length

is

the pelvis necessarily influences the balance of the pelvis 8.

A line-of-movement from the big toe to the

of teaching, emphasis

itself.

heel.

During the semester

was placed on walking with the

toes pointing direcdy

PATTERNS OF SKELETAL ALIGNMENT

196

ahead. This, with decreased

tilt

of the pelvis

ora close to the pelvis, results in a joints, less

and better control

more centered

of the fem-

w^eight thrust at the ankle

pronation and eversion of the feet, and hence reduction of the

inside length of the feet.

A line-of-movement to lengthen

the central axis of the trunk upward. changes in the position of the skeletal parts ultimately contribute to a lengthening of the central axis of the trunk, this line-of-movement is one w^hich promotes many simultaneous changes in the trunk, especially in the alignment of the spine and the position of the head, as the student gains experience with other lines-of-movement. Furthermore, it supports 9.

Since

all

the concept of centered control of both the balance and the the body as a whole.

The

movement

of

an imagined central axis can exert indirectly a strong influence on the efficient performance of all patterns of movement in any activity. If the dancer, for example, wishes to bend laterally as far as possible, he invariably will bend farther wdthout muscular strain by thinking of bending the central axis instead of trying to thrust stability of

his ribs sideways.

Although each line-of-movement is identified by location and direction promote changes in a particular area of the body, the effects of each are all-pervasive. Successful realignment of one part of the body both depends upon and leads to realignment throughout the body. Imagined movement can help to increase the efficiency of the whole person in a manner which can never be equaled by voluntary movement of any part or section of the body. When the central nervous system is free to mobilize muscle coordination to put an idea into action, it has no boundaries to its influence to

within the body.

movement is a mental process, its success depends knowledge and understanding of the anatomical, neuand mechanical facts which support each line-of-movement.

Since imagined

upon the rological,

student's

As the student gains knowledge, he loses his false notions about posture and movement and their expression in the body. He becomes less subject to the influence of postural fads and fancies. He improves his ability to sense muscle strain, and learns how to thwart such strain so that it will not become a painful handicap to his activities.

Bilateral Skeletal

Whereas the

first

study

Alignment

in the

Standing Position

was concerned with

analysis of the effects of

teaching on postural alignment, the second study was concerned solely with analysis of bilateral deviations in postural alignment of the skeletal frame-

work +0

(63, 80). The study included 497 subjects, ranging in age from 17 41 years old, and divided into four age-sex groups. It was hoped that this

relatively large

group of subjects would provide meaningful data regarding

SKELETAL DEVIATIONS IDENTIFIED IN POSTURAL ALIGNMENT

trends in bilateral skeletal alignment in the upright position

among

197

the gen-

eral population.

Bilateral measurements were made on the anteroposterior x-ray photographs of the skeletal framework of the trunk and proximal femora of each subject in the standing position. A vertical line through the center-top of

was established as the line of division between the right and Any skeletal part was considered to be deviated from symmetrical

the sacrum left sides.

alignment

if its

horizontal, diagonal, or vertical distance from a point of

reference was greater than that of its corresponding part from a corresponding point of reference on the opposite side of the structure. Thirty-six of the

measured asymmetries

in skeletal

alignment showed

a rehability coefficient ranging from r = 0.71-0.98, the reliability, in gen-

from the center of gravity increased. Body sway had the greatest influence on the reliability of the position of distal parts of the structure. The correlation of the 36 asymmetries was analyzed to determine those which showed a consistent degree of correlaeral decreasing as distance

in standing

tion with

each other, but a lesser degree with

Patterns of Deviation from Bilateral

all

other asymmetries.

Symmetry

Seven patterns of deviation, the same in each age-sex group, emerged from the analysis of the correlations of the asymmetries. Five patterns were located in various parts of the pelvis and proximal femora, each representing rotation of the pelvis primarily in one of the cardinal planes, with lateral deviation of the femora, mainly in the coronal plane. Another pattern was located in the lumbar spine and represented lateral deviation which was either continuous or in the form of a lateral curve. Finally, there was a pattern of deviation in the shoulder girdle and upper rib-case which represented a difference in the bilateral height of these parts.

The General Pattern of Deviation from

Bilateral

Symmetry The pattern

of deviation in the

lumbar spine and two patterns

in the

=

and proximal femora showed a sufficient degree of correlation (r 0.46-0.76) to indicate a trend toward a general pattern of alignment in the pelvis

The asymmetries entering into the forma0.73showed a high degree of reliability (r

central skeletal structure (80). tion of the general pattern

=

The intercorrelation of asymmetries ranged from 0.20-0.96. Two factors seemed to influence the degree of intercorrelation: (1) the plane

0.98).

in

which the

pelvis rotated primarily to

produce the asymmetry, and

(2)

the distance between the asymmetries being correlated.

Asymmetries representing horizontal and/or sagittal rotation of the had the lowest correlation with lateral deviation of the lumbar spine.

pelvis

This lack of correlation

is

logical, since neither horizontal

nor sagittal rota-

PATTERNS OF SKELETAL ALIGNMENT

198

tion

would have much influence on the

table.

crease

On

lateral slant of the supporting sacral rotation of pelvis in the coronal plane to inhand, the the other

its

height and lateral prominence on one side would markedly influ-

ence the lateral indeed,

it

slaait

of the sacral table as the base of support for the spine;

would tend

to tip the

Asymmetry

Prediction of Bilateral

The

low spine sideways. of Alignment

reliability of the deviations in the

general pattern and the relatively

high degree of intercorrelation of the three patterns of deviation which

formed the general pattern permit a reasonably accurate prediction of the central pattern from the lateral deviation of the pelvis (see Figure 64). For instance, using lateral prominence of the pelvis to the left as a point of reference, the following asymmetries in the central skeletal alignment will tend to occur and be reflected in patterns of movement:

The asymmetry

1.

left, its

on the rotary

of the pelvis appears in

horizontal rotation to the

left,

and

its

its

greater height on the

greater anteroposterior

tilt

The difference in anteroposterior tilt is possible through slight movement at the pubic symphysis and sacroiliac joints. Greater left.

prominence of the

left

buttock often appears wdth the asymmetry of pelvic

alignment.

The lumbar spine

2.

side.

This

on the 3.

is

right than

The

deviates or curves laterally to the right (opposite)

often accompanied by a greater indentation of the waist line

left

on the

left side.

femur is more prominent

laterally

than the right at the level

Figure 64. Skeletal alignment in close agreement wdth the central pattern of alignment, drawn

from an x-ray photograph of a subject of the skeletal study.

SKELETAL DEVIATIONS IDENTIFIED IN POSTURAL ALIGNMENT of the great trochanter,

and the femoral head

is

199

farther from the central

vertical line.

The

direct opposite of the

above occurs when the pelvis

is

prominent

laterally to the right side.

The rotation of the pelvis (see Chapter 5) on two femoral heads, rather than on one only, complicates the picture of deviations in the pelvis and

movement producing them. The posand degree of movement are innumerable.

their interpretation in terms of the sible variations in direction

No

rotation occurs solely in

one of the orientation planes, and

all

rotations of

the pelvis occur together in differing degree from person to person. Hence, it is

not surprising that no two subjects were alike in the degree of their

various deviations in the pelvis.

The

pivotal point of pelvic rotation

is

the femoral joint, which

As distance

is

close

any part of the pelvis from this pivotal point increases, the degree of deviation tends to increase and to vary in direction. Simultaneously, such deviation is accompanied by slight movement at one or both sacroihac joints and the pubic symphysis. Though deviation at the pubic symphysis was easily measured and showed a high degree of correlation with other pelvic asymmetries, deviation at the sacroiliac joints was not. Hence, the study gave no definite information which would indicate whether rotation occurred in one or both sacroiliac joints with the rotation of the pelvis in various directions. Experience of the author with students whose alignment agreed in general with the central pattern of deviation revealed in the x-ray study, and who had muscular to the central line of the body.

pain over a sacroiliac

joint,

of

has indicated that

movememt

usually occurs

one joint only — usually the sacroiliac joint on the side opposite to lateral prominence of the pelvis. In a few subjects the alignment of the lumbar spine was somewhat unusual in that adjustment to a lateral slanting base at the sacral table was made immediately in the lowest one or two vertebrae to such an extent that the alignment of the other lumbar vertebrae above it deviated to the same side as the pelvis did. The joints of the lumbar vertebrae allow more variations in the pattern of alignment of the lumbar spine than that allowed in other pelvic and femoral patterns of deviation in which fewer joints in

are involved.

Measurements indicated a tendency toward outward rotation of both femora in practically all subjects, but the femur with greater outward rotation showed no consistent association with lateral prominence of the pelvis, nor did its outward rotation enter into any pattern of deviation. The conclusion that can be drawn from the central pattern of asymmetry of skeletal alignment, as stated above, is that adjustment for balance in its central area shows a general similarity from person to person and that

PATTERNS OF SKELETAL ALIGNMENT

200

it

can be deduced with a

When

fair

degree of accuracy from lateral prominence

lumbar spine in opposition to that of the pelvis can easily be determined by inspection and/or palpation, it is usually possible to predict the central pattern and its influence on movement of the lower limbs — and this prediction is invariably confirmed by

of the pelvis.

lateral deviation of the

the person's experience.

Deviations in the alignment of the thoracic and cervical spine, though characterized by a high degree of reliability

(r

= 0.73-0.93), failed to con-

form to a consistent pattern of alignment. This observation indicates that adjustment for balance of the spine above the lumbar region tends to be highly individual, and its alignment cannot be inferred from other deviations.

Deviations in the pattern of asymmetry of the shoulder girdle and upper thorax showed a reliability of r =0.71-0.88, but their correlation with

each other was relatively low sex groups.

The

(r

^0.42-0.47), though similar

in the age-

coefficient of correlation of the shoulder girdle pattern

with patterns forming the central pattern of deviation was too low to be significant, ranging from r 0.33 to 0.27 in the age-sex groups. These

=

findings indicate that in normal subjects area, as in the thoracic

and

asymmetry of the shoulder girdle is highly individual and cannot

cervical spine,

be associated with any degree of accuracy asymmetry in the area of the pelvis.

to

asymmetries or patterns of

Handedness and Asymmetry of the Shoulder Girdle handedness associated with asymmetry of the shoulder girdle? In the skeletal study, which had only 34 to 3^ as many left-handed as right-handed subjects, only a minor trend toward such a relationship was uncovered. In right-handedness the left shoulder and left upper rib-case tended to be higher, and the upper three thoracic vertebrae slanted from below upward to the right. The reverse pattern tended to occur with left-handedness. No statistical significance was found for the occurrence of these relationships, however, and therefore asymmetry of the shoulder girdle and upper thorax cannot be reliably associated with handedness. Neither did Huelster (44, p. 189) find a significant relationship between handedness and bilateral contour asymmetry in the shoulder height. She did, however, find a marked relationship between handedness and contour asymmetry at the Is

base of the neck.

The Central Pattern of Skeletal Deviation and Function Lower Limbs

of the

Just as

most people tend

to

show a preference in the functional use show a preference in the func-

of the upper extremities, so do they tend to

SKELETAL DEVIATIONS IDENTIFIED IN POSTURAL ALIGNMENT tional use of the

lower limbs. This difference in functional use

is

201

invariably

related to deviations from symmetrical alignment.

The lower limb

y^hich

is

closer to the vertical line passing through the is, the limb which is more centered in relabe more stable and more reliable for weight muscular work to carry out its function in both

center- top of the sacrum, that tion to the trunk, tends to

support; and

it

requires less

weight support and movement. In fact, the lateral difference in degree of muscle work can quite often be observed in a person as he walks. In any activity

which requires support by one limb, unless

or has

it is

sciously prevented, the limb closer to the center of the

body

been con-

will automati-

be given preference. This observation was also made by Huelster when starting to walk (44, p. 239). The limb farther from the center, that is, less centered in relation to the trunk, cally

as she recorded the leg preference

normally has a greater range of movement than the better centered hmb. This increase in its range of movement results from the concomitant move-

ment

in the pelvis

and lumbar

spine,

which

of their deviations from symmetry. In the

limb, the concomitant

movement

is

in the pelvis

ter to the direction of their deviations

and lumbar spine cannot contribute

augmented by the direction of the more centered and lumbar spine runs coun-

movement

from symmetry. Thus, the pelvis an increase in range of move-

to as great

ment as they can to the less-centered limb. The difference in the use of the lower limbs manifests

itself in

physical activities, whether in athletics, games, occupational

most

movement,

movement. The author has noted that only those persons who have a central pattern of alignment which differs to some extent from the central pattern discovered in the skeletal study will lack any marked or complete preference for one limb over the other.

or everyday

Skeletal

The

Asymmetry and Related Muscle Development

location

and patterns of

skeletal

asymmetry

as

determined from

the x-ray photographs were compared, finally, with patterns of relatively greater muscle development (hypertonus) in

400

of hypertonus of muscles that hypertonus

was

was determined by

who were The pattern

of the subjects

students in posture classes of the author over a period of 3 years. palpation.

The author found

closely associated with the pattern of bilateral asym-

metry of the skeletal structure. Hence, with sufficient skill in the art of palpation (which admittedly takes some time to acquire), the teacher can determine the pattern of hypertonic muscles and interpret it in terms of deviations in skeletal alignment.

some muscles results, as discussed more frequent and continuous work in maintaining the Class I, weight-supporting bony levers; and from their

Relatively greater development of previously, from their

the balance of

202

PATTERNS OF SKELETAL ALIGNMENT

more continuous work III

levers,

in maintaining a supposedly "good" position of Class

such as the ribs and shoulder girdle (see

p. 184).

The Significance of Inefficient Skeletal Alignment (Poor Posture)

From

the results of the two studies

we can conclude

that the significance

of inefficient skeletal alignment resides in (1) the patterns of hypertonic

muscles which accompany the patterns of deviation in skeletal alignment; (2) the lack of suppleness of hypertonic muscles, and hence their tendency

range of movement; (3) the need for increased muscle conovercome the restriction imposed on movement by hypertonic muscles; (4) the increased tendency to injure those joints, ligaments, and muscles that are steadily under strain in the upright position; (5) the increased wear and tear on fibrocartilages, ligaments, and bone itself, which often hastens the development of osteoarthritis; and, finally, (6) the tendency of muscles under strain to become painful, especially in the low back and in the shoulders, and to be afflicted with crippling spasms in response to any movement or activity which finally adds the extra strain which a muscle or muscles cannot endure. As we delve more deeply into the problems of posture and of its skeletal, muscular, neurological, and mechanical aspects, we grow ever more keenly aware that its improvement may be the one factor which, with a proper amount of training, can enable a person to reach his greatest height of attainment in any field of activity for which he possesses the necessary talent and interest. to restrict the

traction to

Part

FOUR

^^^^t^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^'^^^'V^^^^^^^^^^^^^^^^^V

Facilitators for

the Improvement of Posture and

Movement

18 The Posture Laboratory

Much

of the instructional

work

of ideokinetic recoordination for better

body balance and movement is done in the posture laboratory. Because the learning of this method, the practice of imagined movement, is essentially a mental discipliney the posture laboratory should be comfortably cool, free from all extraneous noise and confusion, and softly lighted. The size and equipment of the room depends largely on the number of students to be accommodated in it at one time. The posture laboratory should have tables on which students rest in various positions for their work. A folding table measuring 72 or more inches long, 29 inches high, and 30 inches wide has been found to be useful for all students, regardless of height or weight. It will support two students, heads are at opposite ends of the table. No table should be wider than 30 inches, a width which most teachers can reach as a rule,

when

across easily

their

whenever necessary.

two or more layers of blanket. more important for the teacher than for the student, since it is far easier and much more comfortable to move a hand over a blanketed table than a bare one, especially when the hand moves between the student's body and the table top. Although the floor would be perfectly adequate as a base of support for the student, having the students on the floor tends to be cumbersome and

Each

table should be covered with

This requirement

is

strenuous for the teacher.

have as many low stools (approximately 18 inches long, 12 inches wide, and 12 inches high) as there are students. These are used for work in the sitting position. They may also serve to support the feet when the student sits on the table to do further

The posture laboratory should

work

at the

completion of

his

also

work

in the lying position.

Small pillows approximately 12 inches by 16 inches, are used in many different ways. They are needed for head support in the constructive rest position for

all

students, particularly at

first,

and may be continuously who have

required by those students with relatively deep chests and those

205

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

206

the problem of a forward head with

marked

AND MOVEMENT

suboccipital tension

and

exaggerated cervical curve. Pillows are often used under the balls of the

between the ankles, the elbows, and the knees. A foam rubber, approximately 2 by 4 by 16 inches, placed under the balls of the feet, is better than a pillow to keep the feet from sliding forward away from the pelvis in the constructive rest position. A complete skeleton should always be available for student inspection and study, and for the teacher's use in teaching. Knowledge and appreciation of the skeleton as a weight-supporting and moving structure is of feet, or in side-lying strip of

cardinal importance as a point of departure in the educational procedure in the posture laboratory.

Separate bones also are useful equipment,

especially an assembled spinal

column and

pelvis

and a separate thigh

bone. Besides tables, blankets, stools, pillows, skeleton, and some separate bones, the posture laboratory should have a blackboard for illustrations,

an adas of human anatomy for its illustrations (Spalteholtz [73] is especially good), toys, mechanical gadgets which can be used for illustration of movement in various images, and paper towels to protect the pillows. Traditional contour pictures illustrating the supposedly "good" posture in contrast to various types of poor posture are not advised because they tend to promote voluntary imitation. They do not encourage "thinking through" the body, nor do they increase knowledge of the skeletal framework. Mirrors are not advised, but

may be

if

they are present in the work room they

useful at times for pointing out deviations in a student's

body— but

always with explanation of the deviations in terms of bony relationships, not body contour.

The

clothing of the students

are not restricted by tight

fit

may

vary, as long as the

body and

its

joints

of any part of the garment. Tight clothing,

especially in the area of the pelvis, knees, and shoulder joints, interferes with sensory reports both of change in pressure contact with the supporting surface in rest positions and change in muscular tightness. In the area of the joints that are bent, tight clothing quickly leads to a feeling of muscular strain and a desire to straighten the joint, even though the weight of the

part

may

then distort trunk alignment.

Desirable Attributes for

Good

Training

Most fortunate, of course, is the teacher whose own mechanics of movement are above reproach. Poor mechanics of movement not only set a bad example, but they waste the time and energy of the teacher. Although the posture of the teacher may be far from ideal, it should imagined movement in its flexibility and ease of

reflect the practice of

THE POSTURE LABORATORY

207

movement. With continued experience in using imagery in one's own body, one gains the abihty to anticipate and prepare for the problems which arise

among

benefits to

the students.

The teacher who has

personally experienced the

be derived from the practice of imagined movement

qualified to use

it

is

best

as a teaching tool.

As we have stressed repeatedly, the teacher needs an extensive funcknowledge of the skeletal structure and a clear concept of the skeletal alignment which conforms to the principles of mechanical balance. He must also be able to adjust this ideal to various types of inherited structure, remembering that principles of mechanics remain the same for all types of body build. Going beyond the concept of good postural alignment, the teacher should be able to visualize the skeleton inside the body contour, and to think and analyze in terms of bones and their relationships — always keeptional

mind the primary mechanical function of each section of the skeletal framework, whether it is weight support, or movement, or both, as in the lower extremities. He must also be able to identify typical deviations from good skeletal alignment from the outside appearance of the body and from its movement. The mechanics of everyday movement must be emphasized in each class session. With careful and thoughtful use of the hands, the teacher can become skilled in palpation of relative muscle development and the interpretation of this in terms of skeletal deviations from good alignment. Finally, the teacher needs to know where and in what direction movement in the skeleton must occur to produce a better alignment (Chapter 17). He must prepare the way for the central nervous system to pattern the ideal muscle coordination in response to movement imagined but not voluntarily performed.

ing in

Bodily Positions for Posture

Work

Imagined movement may be practiced in many different positions of and also during movement which is largely automatic, relatively slow, and without exertion. In the rest positions, the broader the base of support of the body and the nearer the center of gravity is to the supporting surface, the less muscle action will be needed to maintain the position — and hence the less established neuromuscular habits will interfere with the neuromuscular coordination patterned subcortically in response to imagery. rest,

The Constructive Rest Position (CRP)

The most frequently used the posture laboratory

is

position for practice of imagined

structive rest position (CRP),

modifications in Chapter 19.

which

is

movement

in

knee-bent position, the condescribed in detail, with its possible

the back-lying,

AND MOVEMENT

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

208

The Side-Lying Position In the side-lying position the to rest

bent

it

at

head

is

supported on a pillow or pillows

in line with the center of the trunk.

The thigh and knee

approximately a 45-degree angle, although one knee

joints are

may be more

bent than the other if this is more comfortable. The shoulders are placed comfortably forward, and the arms rest in front of the rib-case with the

elbows bent. The student can make this position even more comfortable by using pillows to prevent the pull of any appendage on the trunk. Thus, a pillow between the feet, another between the knees, and still another between the bent elbows prevent the weight of the limbs farther from the supporting surface from pulling on the trunk.

wide

If

the individual's pelvis

relative to the waistline, a small pillow can also

is

be placed under the

waistline.

The Face-Lying (Prone) Position Lying on the front of the body is the least favorable position for most is used less frequently than any other position for practice imagery. It is least helpful from the standpoint of the pull of gravity, because of the extended position of the lower limbs. If it is used, the head is turned to whichever side is more comfortable. The arms, with elbows bent, rest on the supporting surface at either side of the trunk or head in the location which is more comfortable, or sometimes more favorable for the work to be done. To prevent the pelvis from being pulled postural procedures and

downward in front (increased anteroposterior tilt) by the function of the Y ligaments, the student should place a pillow or folded blanket of sufficient height under the lower trunk (not the thighs) to allow the thighs to sag forward.

He

can also put a pillow under each ankle

tion of the feet

is

if

the extended posi-

uncomfortable.

The Four-Legged Position In the four-legged position (see Figure 65), the weight of the

body

is

supported on the hands and knees. The wrists, with the fingers pointing straight forward, are directly under the shoulder joints; and the knees are

under the thigh joints. If the extended ankle position is uncommay be placed under the ankle joints. The head, rib-case, and pelvis should be in line with each other; and the upper thoracic spine should not be allowed to sag toward the floor between the shoulder blades so that the shoulder blades look like wings projecting upward from the back. The shoulder blades should be close to the rib-case. The back should give the appearance of a table top sufficiently level and strong to support a weight any place on its surface. The person whose upper thoracic spine sags between the shoulder directly

fortable a pillow

THE POSTURE LABORATORY

Figure 65.

The

209

four-legged position.

be one who has the problem an amount of pulling stress on the sternoclavicular articulations on the front. It should not be allowed, even though changing it voluntarily will produce distortion of other parts of the spine and back. In this position, as in all others, the alignment and relationships of the skeletal framework can be no better than one's neuromuscular habits allow. blades in the four-legged position

of a forward head. Sagging

The

Sitting

The

is

likely to

toward the

floor places

and Standing Positions

Chapters 21 and 22. knee and ankle joints should be no farther apart than the femoral joints, and the feet should point straight ahead. These joints will not be in vertical relationship to each other (see Chapters sitting position is described in detail in

In the standing position the

16 and 17), though imagined movement wdll often result in sway of the body to produce such a relationship momentarily. The arms hang freely at the sides. If they are used at all to aid in maintaining equilibrium, they

The feet may also be placed in a step posione forward and one backward, but with the weight equally divided between the two. This position of the feet will help to maintain the equilibrium of the body as it sways in response to imagined movement. should be used only minimally. tion with

Walking In walking the feet should always point straight

and ankle

joints

and the

foot of

each limb move

ahead so that the knee

in the sagittal

plane of the

femoral joint (see p. 255). Walking with the toes turned out is poor mechanics in the use of the feet. It is all too often a habit of everyday movement, especially of the dancer, which, like various poor occupational habits, wdll

unduly retard progress toward more efficient neuromuscular coordination throughout the body. Therefore, the mechanics in the use of the feet, like the mechanics in all everyday movements (see Chapter 22), must be given voluntary attention, while one concentrates on imagery, especially in the trunk, as the activity proceeds automatically.

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

210

The synergy attention,

of the

movement

and equilibrium

AND MOVEMENT

of walking proceeds without any direct

maintained even as imagined movement

is

is

repatteming muscle coordination subcortically. The student should concentrate on imagined movement before starting to walk, and continue his concentration while walking, which he should do at his regular pace. Concentration on imagery in the pelvis often results in the step's being shortened. Shortening or lengthening of the step, however, should never be

done

voluntarily.

"Walk

naturally, with the

usual admonition after one has located and

arms hanging freely" is the visualizing whatever action

is

the image demands.

Lesson Content

Although the content of each laboratory lesson must be well planned, it

should always remain flexible enough to handle those problems of the

students which need immediate attention, even though their solution

may

require the presentation of facts and principles reserved for a later lesson.

The students

some

followdng are examples of needs for immediate attention which

may have

part of a

at

any time:

movement

tional procedure, or

(1)

muscular pain or

strain; (2)

pain during

pattern either in a sport, the dance, an occupa-

any other

activity; (3)

complete inability to perform

movements vdthout pain, which frequently occurs in the dance; (4) lack of range of movement; or (5) a question regarding the improvement of a technique of a sport. The contribution the posture teacher can make in the last situation is limited to the improvement of posture, that is, to helping the person attain a more efficient machine for the sports activity. That this help can be given has been proven many times in the author's work with athletes. certain

There can be no hard and

fast rules

governing the procedure, nor in the

amount of work that can be accomplished, in each laboratory session. Much depends on the personality of the teacher, the breadth of knowledge background of experience, his ability to use hands both to aid the student in the location and direction of imagined movement and in sensing and interpreting skeletal and muscle change, and his ability to interpret the bodily expression of each student. "at his or her finger tips," his his

When a class has been organized and its members

have a general under-

standing of the method of working, each lesson might proceed with something like the following: 1.

Presentation of facts and principles which support the imagined

movement 2.

to

be presented.

Description and illustration of the imagined movement.

3. Individual

help in locating the imagined

with repeated explanation as

may be

movement and

necessary.

its

direction,

THE POSTURE LABORATORY

211

As a class progresses, successive sessions should enlarge the student's knowledge of the human body as a mechanism for movement. Thus false ideas regarding posture and movement can gradually be supplanted with factual knowledge, and poor habits and practices can be discouraged— especially those which apply to the mechanics of everyday movement. Individual help can be increased, and more time can be spent in determining the problems involved in the progress of each student. Although all lines-of-movement should be known and practiced by each student, the relative emphasis to be placed on each will vary from person to person. Also, the positions for work may be changed or modified, as needed for the particular student.

Records of Postural Alignment

The most

objective records of postural alignment are x-ray photographs

of the skeletal structure in the standing position with the weight evenly

distributed

on the

feet, the

arms hanging freely

at the sides,

and a plumb

line placed beside the subject to indicate the line of gravity. Unfortunately,

an expensive process which usually can be employed only for research or in an individual case referred for medical assistance. Photographs, both back and lateral views, with a plumb line beside the body, provide a record which can be compared with later photographs, providing the subject is given the same directions in regard to the standing position. Since a record is desired of the student's habitual alignment when this is

standing, the teacher should not encourage

him

to

assume a posture con-

sidered "good"; instead he should stand as well as possible with ease.

If

records are to be kept for individual students, then photographs usually are economically feasible.

Descriptions of deviations in postural alignment are the least reliable

and assigning a grade to anyone's "posture" is a presumptuous undertaking. The results of any study of posture which is based on the subjective judgment of so-called experts are highly questionable and can only cast doubt on the entire field of posture knowledge and procedure. Yet we have arrived at many of our prevailing dogma concerning posture in just this manner. In comparing either x-ray photographs or photographs of subjects taken at different times, remember that a very small change made in joint relationships can produce a marked amount of ease and freedom of movement. Likewise, there may be a far greater change in peripheral bony relationships, especially in the relation of the pelvis and ankles, than the very tiny change at weight-supporting joints would seem to indicate. A day-to-day or week-to-week memory of the posture and movement problems of each student is very important for both the student and the

of

all

records,

212

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

AND MOVEMENT

Any teacher may want to make note of particular things to remember about each student, especially when the number of students is large. teacher.

But as a teacher becomes more familiar with individual problems, especially there is reliance on palpation of muscles to determine the student's progress, the need for records grows less and becomes of historical value only.

if

Responses to Imagined Movement

As in any educational procedure, students will respond differently to imagined action as taught in the posture laboratory. Some students will need repeated explanation and individual help while others may grasp each idea quickly and will direct their attention at once to concentration on the image. In doing so, this "quick" student may forget the teacher and look into space or even close the eyes for better concentration. Any student who appears tense is not grasping the idea of how to proceed. In CRP (the constructive rest position) tension may be manifested in lack of ease in the student's hands and taut muscles — especially of the shoulders and neck, the abdominals, the hamstrings, and in resistance to any slight pressure on the rib-case (stiffening against it), or to any of the teacher's efforts to move any part of the body. The reason for such "holding" must be discovered. It may be that, in the presentation of imagined movement, some statement conflicts with a belief about movement. The student may be unable to accept the idea that changes in his body can be made without putting forth any muscular effort, he may fail to comprehend what is required of him in response to directions given, or he may simply be a "tense type" of person in practically all situations. The "tense" person presents a difficult educational problem because helping him involves changing a personal trait rather than a habit. Images must be developed to which the student can relate and which ease tensions. Sometimes a student will report pain following a practice session by himself and will be inclined to blame imagined action for it. Usually the problem lies in his giving voluntary aid to imagined action without realizing it. This can occur even among those skilled in the procedure, especially when the student is particularly eager for results. On the other hand, there are times when release of muscle tightness in one area of the body exposes a problem of muscle strain of which the student was not formerly aware. If this is the reason for the pain, pillows may be used temporarily to make the rest position more comfortably, and more emphasis must be placed on imagery which will recoordinate muscle action rather than on that which relaxes muscle tightness. Movement of very small range which requires work of the muscles whose antagonists are those in the area of pain is the most effective. Determining what such voluntary movement should be — and the location and direction of imagined movement however,

is

frequently very difficult,

if

to

accompany

it

—

not impossible.

I

THE POSTURE LABORATORY

213

Benefits of Posture Education and Training

Many factors influence the student's progress in attaining better posture its concomitant benefits. Among these are (1) the degree of the original

and

deviations from good alignment, (2) the frequency of posture lessons, (3) the amount of help given by a teacher, (4) the demands of one's occupation or daily activity, (5) the extent to

which there

is

daily practice,

and

(6)

the mechanics of everyday movement. Persistence in bad habits of sitting, standing,

and the use of the body

in the

motor

skills of daily

movement

greatly hinders progress toward neuromuscular efficiency in both posture

and movement.

improvement vary in numand degree with each person. Nevertheless, they usually in-

Students' reports of the benefits of posture ber, kind,

clude the following. 1.

A more

slender figure and better carriage of the body both in

standing and in movement, without effort or thought of "holding" a position or attitude. 2

Increased ease of

movement and

less fatigue

from the day's usual

activities.

3. Elimination of

muscular pain and, concomitantly, increased aware-

ness of both muscular strain and what to do about

becomes

it

before

it

painful.

4.

Elimination of previous awkwardness in some situations, and

5.

Increased

6.

Greater reHabiUty of balance and increased safety in movement.

7.

Better sleep and increased benefits from very short periods of

8.

Increased factual knowledge and understanding of movement,

greater ease in the presence of other people.

with more

flexibility.

ability to evaluate

benefits or possible

harm

rest.

popular articles on posture and the

of procedures in various commercial

establishments.

and often disappearance, of psychological and emotional problems as ease in the body increases. A more dynamic body freed from the efforts of "holding," and therefore prepared to recover quickly from any situation of im-

9. Easing,

10.

balance before

Of

it

proceeds too

far.

all ages and which can be claimed logically to result directiy from better skeletal alignment: (1) a more slender figure, (2) increased flexibility in joints in accord with their design, and (3) decreased expenditure of energy. These benefits occur simultaneously, and

many

the above benefits reported by the author's students of

different occupations, there are three

they can be measured.

214

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

The

AND MOVEMENT

which accrue from improved posture are they exist, for surely the release of muscle Undoubtedly highly individual. strain and tension has vicarious benefits on various vital functions. Health claims, however, are not essential to support the need or value of posture improvement. The three benefits mentioned above are quite sufficient. extra health benefits

I

19 ^^^^^^^^^^t^^^^t^^^k^i^V^^^'N^^t^^^^^

Constructive Rest

The

physicist defines a

body

are in equilibrium and

human body

at rest as a condition

when no work

is

"when

all

opposing forces

being done." Physically, for the

be at rest, then, it theoretically should be in a position that requires no muscular effort. Physiologically, rest gives time for the bodily processes to return to minimal activity, thus providing a period of recuperation. Rest, therefore, is physiologically essential to man's activities; and the value of daily rest and the knowledge of how to attain maximal benefits from even a short period of rest should be part of the education of to

every person. Unfortunately, youth with learning fully the

its

quick recuperative powers considers

how to rest as nonessential, and many adults fail to appreciate many benefits derived from proper rest. Yet knowing how to rest

good mechanics in the use of the body. Both play a part in thwarting the harmful effects of inefficient neuromuscular habits which both intensify with age and set the background for a goodly number of muscular aches and pains, especially backaches. is

as important as understanding

The Constructive Rest Position

The position of the body for constructive rest (CRP), not for sleep (see Chapter 22), is one in which the pull of gravity aids in reducing muscle strain and in balancing the relaxation of muscles throughout the body. It is similar to the "hook-lying" and "physiological rest" positions. The requirements of such a position are: 1. The body is to be supported by a solid, level surface, such as the floor or a table (never a bed), either of which may be covered with layers of blanket or a rug. (Hereafter the supporting surface will be referred to as the floor.) This support becomes the frame of reference for judging changes which occur in the body during the period of rest, and from day to day. 2.

As large an area of the body as possible, in view of

its

structure

and

215

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

216

the ligamentous support around

its joints,

AND MOVEMENT

should rest on the floor; and

the center of gravity of the body, located in the pelvis, should be as close to this base as possible.

The

body should be such that approximate mechanical balance; that is, the distribution of its structural weight should balance the body so that no muscle work need be added to maintain equilibrium in the position. 4. The arrangement of the upper and lower extremities in relation to the trunk should be such that as much of the weight of each as possible will press toward its articulation with the trunk. 3.

relative position of the parts of the

the skeletal framework

itself will

Assuming the Rest Position

To meet the preceding requirements, one should follow these directions: 1. Assume a back-lying (supine) position on the floor with a small If you are slender and already have relatively good posture, you may need a pillow only for your first several times of practice. A deep-chested person needs a pillow of greater depth to maintain the ahgnment of the head with the trunk. If you tend to have a forward head, you definitely will need a pillow to help release tightness of suboccipital muscles at the base of the head. Rest your head on the pillow, placing the chin as close to the front of the neck as is com-

pillow under the head only, not the neck.

fortable. 2.

Bend

the thigh and knee joints to bring the feet to rest on the floor

as close to the pelvis as

is

comfortable.

be approximately 90 degrees. be

felt at

the knees;

if

If less

more than

The angle

than

this,

this,

of the knee-bend should

muscular strain

may

soon

the influence of the weight of the

on producing a better position of the pelvis will be diminished. lie with the legs extended while resting on the floor, for the Y ligaments will pull the front of the pelvis downward toward the feet and hollow the low back. The difference in the height of the low back from the floor when the legs are extended and when they are bent at the knee and thigh joints can readily be felt by placing the hand under the low back. This is a prime example of how the position of the lower limbs in relation to the pelvis can affect the alignment of the spine whether lying, sitting, or stand-

thighs

Never

ing. 3.

Place the feet, preferably in line with the knees and thigh joints, so

the toes point straight ahead.

They probably

will not maintain this position

very long unless you are in the habit of walking with the toes pointing straight ahead. Even correct positioning, however, may not overcome the effects of tight is

outward rotators on the back of the

pelvis

when

the body

at rest. 4.

Rest the arms across the front of the chest, but do not fold them or

grip any part of the

body with the hands

(see Figure 66).

CONSTRUCTIVE REST

217

Figure 66. The constructive rest position (CRP).

Counteracting the Effects of Hypertonic Muscles It is

the

not

CRP

A

uncommon

at first

many people

for

to find

it

impossible to maintain

without holding the legs and arms in the prescribed posi-

frequent experience, as one relaxes,

knees to fall apart, shde off the chest. This overrelaxation results from the lack of balance of tonus of muscles around the joints. Hypertonic muscles are less supple than well-tuned ones, and they relax less quickly. Hence, they pull more strongly on bones tion.

the feet to shde

away from the

pelvis,

is

for the

and the arms

to

than their opponents do, and thus distort the CRP. To counteract the pull of hypertonic muscles, the following aids (see Figure 67) are advised: 1

knee

Tie the thighs together just above the knees so that the center of each aligns

with the center of

its

thigh joint (see p. 67 for the

method

of

By doing so, you and tighter muscles on the back of the pelvis and outside of the thighs from pulhng the knees apart. Unless you engage daily in very strong activity, you will be able in time to omit the ties and brace the knees upright by the position of the feet, as described below. 2. Place a lift, as a roll of rug, newspaper, blanket, books, or a strip of foam rubber under the balls only of the feet to counteract the tendency of the tight muscles on the front of the thighs (the quadriceps extensors) to straighten the knees and thus move the feet away from the pelvis. If the rest position is assumed on the floor so that the feet are next to a wall, the wall itself can hold up the balls of the feet. The lift prevents the need for contraction of the hamstrings on the back of the thighs to maintain the finding the exact location of the thigh or femoral joint).

will prevent the stronger

bent position of the knees. 3. For a very few people, turning the toes inward (pigeon-toe) or moving the feet farther apart will serve to brace the knees upright so they do not fall apart. Even if the distance between the feet changes, however, the

knees should remain in

line

with the thigh

joints.

When

there

is

balanced

relaxation (or tonus) of muscles around the joints of the lower limbs, the

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

218

AND MOVEMENT

Figure 67. The rest position, illustrating the means of counteracting the pull of hypertonic muscles.

feet will point straight ahead, in the 4.

same

and the ankle, knee, and thigh

joints will

be

sagittal plane.

Tight muscles between the shoulder blades and spine will tend to

back and hence cause the arms to slide off the front of the chest. The arms may be slipped through a loop of cloth to support them just above the elbows so that each elbow is in line with the thigh joint on its side of the body. But the need for support can usually be eliminated by following the procedure of hissing with the arms resting beyond the head, as suggested on p. 278. pull the shoulder blades together in

Modifications of

For

many

tiie

Constructive Rest Position

beginners

it is

not only impossible to maintain the prescribed

itself may at first be uncomeven painful. For these students the teacher may be tempted to modify the CRP to provide increased comfort. Such modification should be done with caution, however, for invariably the chosen position will favor continued tightness of the very muscles which cause the discomfort and so are in greatest need of relaxation. The sensation of discomfort or pain always occurs in areas of overly tight muscles and in poorly aligned areas of concentrated pressure of body weight on the floor — problems which can best be remedied through practice of the rest position. For example, in the person whose anteroposterior pelvic tilt is exaggerated habitually in the standing position, often with a prominent abdomen, the contact of the back of the pelvis with the floor tends to be much too small in area and always too close to the lower end of the sacrum to be comfortable. Both marked underweight and poor posture, with its accompanying patterns of muscular tightness, contribute to early discomfort in the rest position. There are various ways the rest position may be modified to reduce or even eliminate problems of discomfort or pain until a more balanced relaxation of muscles has been achieved. Some ideas are to:

rest position

without aids, but the position

fortable or

1.

Put more padding on the

2.

Place a small pillow under only the lower part of the pelvis.

floor.

CONSTRUCTIVE REST 3.

219

Lie on the floor with your seat close to a lounge so that the lower legs rest

on the lounge

(or a chair seat)

with the knees directly above

the thigh joints. 4.

Place a pillow under the lower back, as well as under the lower part of the pelvis.

The low back

pillow,

however, should be eliminated

as soon as possible. 5.

Bring the knees to rest on the chest for a few minutes to relieve areas of weight pressure on the back of the pelvis.

6.

on the side temporarily, and rub the hurting areas if is continued, however, be sure to put more the head to align it with the trunk (see Chapter 18). under support

Turn

to lie

possible.

If

side-lying

Cautions Regarding Rest

The

following cautions will help the student avoid mistakes often

in the early practice of constructive rest.

They should

aid

him

made

in achieving

the maximal benefits from constructive rest.

you may consider good. Follow you feel straight. Adjust your body at any time for comfort, but never for an alignment you may think is better. The notion that the low back should be "flat" may lead some 1.

all

Never

force the

body

into a position

directions for assuming the

students to force

it

CRP,

lie

so that

against the floor. In the

first

place, the idea

is

false

(Chapter 16); in the second place, it requires muscular work which interferes with the objectives of balanced relaxation. 2.

The length of time you can rest without discomfort increases with CRP. The period of rest should probably never be longer

practice of the

20 minutes is advisable. Regular daily rest, howyou can finally attain a fair degree of relaxation in 5 or 10 minutes if no more time can be spared for it. The period of rest needed depends on the degree of fatigue, the pressure and strain of the day's activities, and the amount and intensity of the muscular work perthan 45 minutes; ever,

may mean

at least

that

formed. 3. If at all possible, rest

pains or

if

your posture

is

twice a day, especially poor. Rest

especially valuable at the close of the day's

and one

if

you tend

may be taken any

to get

time, but

back it

is

work before an evening meal,

two sessions of rest are impossible, the just before retiring is probably more important because it can contribute to better sleep and to more complete relaxation during sleep. 4. To get up from the rest position, always roll over on the side; then, if resting on the floor, come to the four-legged position with the weight on the hands and knees and get up slowly to avoid any possible dizziness from sudden change to the upright position. To retain as much as possible of the beneficial effects of rest on trunk alignment, never bring the trunk just before retiring at night. If

220

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

AND MOVEMENT

any upright position from the back-lying position without first turning to rest on the side. 5. Each student will sense his progress in his own way, but he is likely to notice some or all of the following: (a) the areas in which the back touches the floor, especially the back of the pelvis, increase in size; and any discomfort in these areas either lessens or disappears entirely; (b) the arms rest more comfortably across the front of the chest; (c) less muscle strain is felt in many areas of the body; (d) there is a feeling of greater relaxation and the body seems lighter and easier in movement; (e) muscle strain is more quickly noticed in the day's activities, giving warning of the need of rest; (f) sleep is often improved; (g) "nervousness" and general tension decrease; and, finally, (h) changes occur much more quickly after assuming the CRP, so that one must adjust his position for comfort very soon after lying down on what has become a friendly support. 6. Some people are prone to fall asleep in the rest position. If they do, their legs are likely to sag to one side to distort the rest position and produce muscular strain and stiffness. If you are such a person, place the feet as far apart as comfortable, turning the heels out and the toes inward, as a means of keeping the knees upright if you should fall asleep. If the lower legs are resting on a lounge or chair, no harm comes from falling asleep. If the knees tend to sag to one side or the other as you rest, bring them to the upright position and adjust the position of the feet again. 7. To accumulate and retain the good effects (both in muscles and in skeletal alignment) which can occur with rest, it must be practiced daily, to

at least once. If

it is

practiced before strenuous activity the activity tends

be easier; if just after strenuous activity, the muscles engaged most strongly in producing movement are given a better chance to relax and thus to reduce the tendency toward less suppleness through their overdevelopment relative to other muscles. Before a "trying performance," it is always advantageous for the performer to start with minimal muscular strain, which can be gained in constructive rest. to

Making Rest Constructive framework and the function of its the body other than that described

In view of the design of the skeletal

is no arrangement of above which distributes its weight in such close conformity with principles of mechanical balance. Thus the position itself is conducive to rest of a constructive nature insofar as the pull of gravity promotes a decrease in muscle tightness. Rest alone, however, will not change neuromuscular coordination to place the framework in a more efficient alignment in the upright position. The most effective procedure for changing the upright alignment is concentration on imagined movement in the body without

ligaments, there

CONSTRUCTIVE REST exerting any physical effort. This ideation results in

movement

is

221

the ideokinetic process in which

of various parts of the skeletal framew^ork;

no physical effort is put forth, because voluntary movement would interfere with the subcortical planning of muscle coordination in response to ideation. it

does

this

only

if

20 Imagined Movement:

An

Ideokinetic Facilitator

is the driving force of all creative endeavor, and stimulating and challenging the student's imagination is the most crucial ingredient in successful teaching. In the ideokinetic approach for posture improvement, however, the need for challenging the imagination becomes even more important than usual. We rely on it to bring about the subcortical patterning of muscle coordination which will produce and maintain an efficient

Imagination

alignment of the skeletal machinery.

When a person imagines movement, putting forth no voluntary effort to aid its execution, the coordinated action of

the imagined

movement

muscular

muscles which produces

be patterned subcortically. Imagining the it involves no muscular effort by the subject, because muscular effort interferes with the skeletal changes which the imagined movement is designed to produce. To change skeletal alignment by imagined movement, therefore, one needs to know where and in what direction the spatial relationship of bones must be changed to attain a more efficient structure. Having established this, one needs only to concentrate on visualizing a movement that will promote these changes to occur in the various places in the body. It will take time to establish more efficient neuromuscular habits; they are attained only through repeated practice.

movement

is

will

a thought process only;

Imagined Movement Versus Voluntary

The

Effort

ideokinetic approach to better skeletal balance through the use

movement is a radical departure from the long-established technique of relying on the volitional effort of the individual to "put" and "hold" the parts of his body in a better alignment. The old technique preof imagined

scribes the practice of exercises to strengthen

weak muscles which

often considered to be the cause of poor posture, and

222

it

are

accounts for the

IMAGINED MOVEMENT: AN IDEOKINETIC FACILITATOR

223

many admonitions concerning

posture which have come into common use. and teachers exhort Parents children to stand tall, stretch up, put the shoulders back, hold the head up and the chin in, tighten the "stomach" muscles, flatten the low back against the floor if supine lying, or against the wall if standing, and finally (the most reprehensible of all admonitions), to tuck the pelvis under. These exhortations are the province of the drill sergeant and the exercise master, but not of the educator. The concept that poor posture results from poorly developed or weak muscles in certain areas of the body is a faulty premise to begin with. The body's response to poor structural alignment, regardless of cause,

is

to

develop patterns of greater muscle activity to cope with the added work load required to maintain equilibrium in an unbalanced structure. Hence the problem lies in the estabhshed neuromuscular coordination which dominates the subcortical patterning of muscle response in all voluntary movement. Voluntary movement to increase strength in the weak muscles,

which undoubtedly

exists,

will simultaneously increase strength in the

stronger muscles also, because of the prevailing habits of neuromuscular

movement uses the old habits and even tends to them more firmly. It maintains the pattern of overdevelopment of muscles which correlates with the existing deviations from efficient structural alignment. Thus neuromuscular habits of coordination are intensified by voluntary efforts to improve posture, and there is no salutary coordination. Volitional establish

on the internal mechanics of structural alignment, even though outbetter. Only by changing the coordination of muscles toward patterns of balanced action around, and close to the joints of fulcrums of the weight-supporting Class I levers of the framework, can the structure simultaneously be brought into better alignment and increased conformity with principles of mechanical balance. No amount of study or work on the mechanics of the body in relation to outside objects will ever substitute for consideration of the internal mechanics of its bony levers. This is basic to the highest level of accomplishment in any field of activity. The application of imagined movement as a teaching method departs from volitional techniques by emphasizing change in the subcortically controlled neuromuscular coordination. Simply stated, the student is instructed to concentrate on envisioning movement occurring within his body without contributing any effort to its performance. In fact, the contribution of any voluntary effort negates the influence of the imagined movement on the subcortical patterning of muscle coordination. This does not mean that imagined action cannot be used while movement is being performed voluntarily, but in this situation the imagined movement cannot relate to the moving part or parts. Instead it must relate to some other nonmoving section of the body (Chapter 23). effect

ward appearance may seem

224

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

The Premise

for

AND MOVEMENT

Imagined Movement

Why is the teaching of imagined movement the most effective means of improving neuromuscular coordination? Certainly in the realm of mechanics the need for mechanical balance of a machine for efficient performance without undue wear and tear goes unchallenged. This balance is built into The human body obeys the same mechanical laws as any machine and, therefore, it too must meet the same structural requirements the machine.

for efficiency in movement. Because of the design of the skeletal framework, however, it can never be aligned for absolute, stable mechanical balance. In any upright position there must always be some muscle and

hgamentous action working to maintain balance in which, ideally, strucconform as closely as possible with principles of mechanical balance. Since there are so many adverse influences on the development of the muscular patterns of action necessary to balance the body in the upright position, there is an ever-present postural problem of varying degree in all individuals. In any person, at whatever age, the upright position is maintained automatically, which means that his own established neuromuscular habits are in control to such an extent that his figure and movement help to identify him as a particular individual. When postural alignment is good, the basic neuromuscular habits of coordination which maintains its equilibrium are likewise good; but when postural alignment is poor the basic neuromuscular habits are inefficient and become a handicap to good movement. Considering the role that subcortically patterned muscular action plays in all movement, and the fact that this subcortical patterning cannot be changed through voluntary effort, it becomes obvious that the only way to improve skeletal alignment is through influence from the cortical level — that is, through education basic to the understanding of movement and through ideation and concentration on visualizing movement in the body. This ideation is effective only when the student rehes completely on mental activity as it deals with facts, and on an imagined movement without voluntary effort. Imagined movement cannot be introspected; it is a spontaneous response evoked as a natural concomitant of the purposive act— the idea of movement. Its effectiveness is based on the premise that the central nervous system will pattern subcortically the muscle action which will obtain the visualized goal of movement (12) in only one way, namely, the most efficient way for the purpose. It can do this only when voluntary aid is not tural alignment will

imposed.

imagined movement draws on the sciences, especially It is impossible to devise meaningful and effective images of movement within a structure that is Httle known and only vaguely understood, and it is likewise an exercise in futility to devise a movement

The teaching

of

anatomy and mechanics.

IMAGINED MOVEMENT: AN IDEOKINETIC FACILITATOR to

be imagined that disobeys

all

fundamental laws of mechanics.

important to understand the nervous system's role in

movement

It is

as

225

also

both the

communicator, which sends and receives messages, and the coordinator, which patterns the muscle work which makes it possible for man to achieve his goals, whether they He in an occupation, recreation, sports, or the arts. Both the teacher and the student must be able to appreciate fully and reall movement (Chapter 15). know and understand the principles of the function of muscles than it is to know their names, origins, insertions, and individual functions. On the other hand, the posture teacher who wishes to

spect the role of the nervous system in It is

grow

much more

important to

and creative

must study muscles reframework from the deepest to the most superficial layers, be acquainted with the recent knowledge revealed through research, and especially be familiar in skill

ability in his teaching

peatedly, be able to visualize their alignment on the skeletal

with the contributions of the early outstanding authorities in the

field of

movement, such as Beevor (6), Duchenne (23), Winslow (89), and Wright (92). Today's knowledge of the muscles and the nervous system is vast but by no means complete, and research continues to reveal facts which increase our understanding of the complicated process of movement.

Identifying Postural and

Movement Problems

must quickly identify and assess the body alignment and movement among the students. In order to do this, the teacher needs (1) a concept of good skeletal alignment based on facts of anatomy and mechanics, and adjustable to differences in body build; (2) knowledge of typical faults of posture, and the ability to locate the key areas of poor relationship of parts of the skeleton; (3) the abihty to determine where and in what direction movement is needed to bring the alignment of the skeleton into closer conformity with In every posture class the teacher

severity of various problems in

principles of mechanical balance; (4) the ability to note restriction of range

and direction of movement in the movement patterns of each student; (5) the abihty to assess the degree of integration of the trunk both while standing and during movement; and, finally, (6) the ability to detect false notions about posture and movement as manifested by the appearance and use of the body.

The posture teacher who

is

skilled in palpation of muscles to

determine their relative degree of development and in the interpretation of muscular development in terms of skeletal alignment has the advantage of being able to confirm the conclusions drawn from observation. However, the constructive use of the hands in teaching posture is never any better than the factual and functional knowledge the teacher has of the body.

human

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

226

Inefficiency

Imposed on Subcortical Patterning of Muscle Action

There are many ways

in

which

patterning of muscular action.

inefficiency

Some

and

is

built into the subcortical

inefficiency results

some

from the postural

can be attributed to teaching. The criticism often given activity teaching, both in schools

exhortations previously mentioned, but activity

AND MOVEMENT

in studies of

many types, is that

all

also

too often

it

lacks uniformity of termi-

nology, conciseness of explanation, and accuracy of description. This inconsistency,

among

which extends

to a

wide range

of activities,

is

even found

To confuse the student further, describe and demonstrate a movement

teachers within a single institution.

sometimes the activity teacher will and frequently the description and demonstration will appear to be totally unrelated. This confusion is endemic to sports and dancing, but it is by no means limited to them. A student exposed to a number of inadequacies by different teachers often winds up with utterly confused concepts of movement and with misguided beliefs which cannot help but adversely influence his subcortical patterning of neuromuscular coordination. Thus the beliefs and the most frequently practiced patterns of movement are reflected in the body alignment and in its movement.

That Which Moves

in

the Imagination

That which the individual visualizes in movement in his body may be bone itself, as the round head of the femur moving inward to snuggle close to the inside of its socket to close an imagined gap between the two. It may be a mechanical gadget, as a sliding curtain rod located in the center of the trunk elongating upward under the center-base of the head to push it upward. It may be something fanciful, as growing an Alice-in-Wonderland neck of great length. In each case, movement occurs only in response to something which is visualized. The nine lines-of-movement discussed in Chapter 17 identified both the location and direction of force needed to improve skeletal ahgnment. In view of these lines-of-movement, it should, therefore, be necessary only to visualize a force (albeit the resultant of straight line properly located in the sults.

Unfortunately,

it is

many

framework

forces) at

work along a

to obtain the desired re-

only the rare abstract thinker

whose imagination

be stimulated by the concept of a theoretical force moving along an imaginary straight line. Consequently the teacher must design images dewill

picting forces

and their direction of action

to

which the student can relate teacher must have a

own knowledge and practical experience. The repertoire of many images for each line-of-movement, from

his

since all images are not equally effective in all students, and because an image used repeatedly tends to lose its value as a challenge to subcortical patterning of muscle

IMAGINED MOVEMENT: AN IDEOKINETIC FACILITATOR

227

There are times when no familiar imagery will solve a problem. Students engaged in strong activity sometimes suffer a highly specific muscular problem which does not respond to the typical line-of-movement images. In these cases images for the specific area must be designed in the midst of teaching on the basis of existing bone alignment and relative muscle action — a most interesting challenge to any posture teacher. coordination.

Education

Teaching in the posture laboratory provides the freedom from pressure and a favorable atmosphere for movement education which no other part of an activity program can provide. In fact, real progress cannot be made without the posture laboratory. Since results are gained through thinking (ideation), every possible

means

of challenging the

student must be used. Every line-of-movement with deals with specific parts of the skeletal framework,

mental

its

activity of the

appropriate imagery

and together they deal

with the entire structure as a unit. There should be a graphic description of the mechanisms involved in each line-of-movement, their location, and the suitability of their design for their particular function in weight support and movement. Such descriptions should be illustrated in various ways on the skeleton — by drawings, pictures, toys, individual bones, and comparisons with machines, all of which help the student to build a sound concept and an accurate mental picture of how the body balances and moves. Throughout such explanations and illustrations, the student should be urged to visualize and locate in his own body the skeletal mechanisms being discussed. Early in his laboratory experience he should be given an explanation of the role of the nervous system in movement. This need not be complicated, but it should be extensive enough to give the student a realization of the very hmited extent of voluntary control over movement, of the folly of trying to control any of the muscle work in movement directly, and of why exercises and the voluntary movement of parts of the body into suggested positions of alignment are neither the answer to posture nor the complete answer to

movement problems. The Construction

of Imagined

Movement

Experience in the use of imagined action in teaching posture and in movement has shown that the central nervous system makes no mistakes in choosing an efficient neuromuscular action in its response to visualized movement, if such movement is allowed by the desolving problems of

and physical laws, and when there is no intermovement. Imagining a movement for which the not designed elicits either no response or an uncon-

sign of the skeletal structure ference' from voluntary skeletal structure

is

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

228

scious increase of general muscular tension.

visualized

movement

has also been found that

across the line-of-action of muscle or muscles, or in

with the direction of muscle

line

It

AND MOVEMENT

fibers,

produces relaxation of these mus-

cles.

The

followdng principles

may

serve as guides in designing

v^hich can be imagined in the body.

To

movement

successfully use these principles,

needs an extensive functional knowledge of the its typical deviations from efficient skeletal structure, alignment, and the location and direction of movement needed to improve body alignment. 1 Each imagined movement must comply with the design of skeletal structure, especially its joints and the movement they allow. 2. The direction of imagined movement must promote change in position of weight-supporting parts to bring them into better conformity with principles of mechanical balance to the extent allowed by the design of the skeletal framework. 3. Imagined movement must obey physical laws in that force of some type produces the movement, even though the movement may be visualized without regard to what produces it. If the student asks how the imagined movement is produced, whether by the pull of gravity as some muscles release their tightness, or by change in coordinated action of muscles, the teacher must be able to answer his question. 4. The anteroposterior curves of the spine should never enter, as a whole, into the construction of an imagined movement of the entire spine. The only imagined movement which influences the alignment of the entire spine is either lengthening down the back, or lengthening the axis upward. Imagined movement may be related, however, to a single vertebra or to any complete curve of the spine, either lateral or anteroposterior. however, the teacher its

first

ideal alignment,

Imagined movement should never be described in terms of muscles is too extensive and complicated to understand even if it could be determined. 6. Imagined movement must be designed in terms of structures which are familiar to the students. No one can build a picture in his mind's eye out of material with which he has no experience. For instance, an accordion is familiar to most if not all people while a mortise is not. 7. Imagined movements tend to lose their challenge to thinking with 5.

or their action, for this

continued repetition; furthermore, they do not appeal equally to all people. For this reason it is necessary to design and use many different images for each line-of-movement.

An

imagined movement may not be suitable for all the various posibody may assume for posture work. Some images may be changed somewhat for different positions; others may be suitable for only one 8.

tions the

position.

IMAGINED MOVEMENT: AN IDEOKINETIC FACILITATOR

229

The Presentation of Movement To Be Imagined As stated above, posture teaching is an important educational discipline. of each image affords valuable opportunities to supply factual information which is useful not only for the moment but also throughout life. Posture training will give the student the knowledge with which to evaluate the degree of truth in the ubiquitous writings on fads promoting "cure-all" solutions to "figure" problems. No one except the person himself can change his basic patterns of neuromuscular coordination; and therefore both his figure and factual knowledge (not opinion) are needed to guide his work. Imagined movement does not lend itself to demonstration by the teacher since the movement is not actually performed. Its effects can be noted in a student's body, however, as the teacher directs him in his imagined movement, especially in the standing position in which a remolding of bodily

The presentation

alignment

is

readily observed.

tarily imitated.

Hence the

What

is

observed, however, cannot be volun-

teacher's ability to

communicate images

in a

man-

ner which will stimulate the mental response of the student becomes of utmost importance; there is no other way to improve the basic neuromuscular coordination throughout the body

The

more promptly.

following principles for the presentation of

movement

to

be imag-

ined apply mainly to work in the posture laboratory, although the activity teacher

change 1

may also use them, own body.

especially

if

he has used imagined action

to

his

State the purpose of the imagined

movement

in terms of the skeletal

it should change, and why such change is needed. Use a graphic description of the movement to be visualized, illustrating it when possible on the skeleton or with a toy, a picture, a drawing, or a comparison with movement of a machine. 3. Be specific in locating the imagined movement in the body and the direction it is to take. This can be done on a skeleton, on the student's body, or on the teacher's body. Preferably it should be shown first on the skeleton, then on the student's body. 4. Be clear and precise in the description of movement to be imagined; and proceed slowly enough to allow the student time to locate and visualize in his body what is being described. Describe it first for the class as a whole, then again when individual help is needed as the teacher moves among the

relationships 2.

students.

any description. Talking too much on the action to be imagined. 6. Use freely such words as imaginey visualize, as if, watch, and pretend. The author seldom uses the term relax, mainly because of its negative implications. When it is used, emphasis is placed on "balanced relaxation" of 5.

Use

as

few words

as possible in

interferes with the student's concentration

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

230

muscles, and this in reality

efficiency of

is

AND MOVEMENT

muscle coordination. Efficiency

cannot be gained by relaxation (diminishing work in muscles) or by voluntary movement. It is gained through the subcortical response to ideation—

imagined movement.

Never

7.

tell

a student to "feel" an action taking place; this

the cart before the horse.

One

feels the results of the change.

first

is

putting

imagines to produce a change, then

Imagining prompts outgoing messages from

the central nervous system to produce change in muscle action; the feeling of such

change

is

then reported back to the central nervous system by the

proprioceptors scattered throughout the body. However, a student

be asked to compare or restriction of

his feeling of

movement

such items as muscular

may

sensitivity, pain,

before and after the practice of imagined

movement. 8. Give frequent warnings against helping an imagined movement. There must be no physical effort put forth. Helping occurs frequently, even

among

those with experience in using imagery. Sometimes, with these

warnings, students should be told that if

not, they

need not be concerned,

if

they note results, this

for they

have

is

good; but

at least contributed to

general ease in the body.

Take time to repeat and clarify ideas so that the mental picture of movement to be watched will be precise, especially when the imagery

9.

the to

be used has been presented in a previous

class session,

and

it is

not fully

understood.

While teaching, talk with the voice free from strain and without all imperious exhortations to complete the task. Thinking does not proceed on command, nor does it follow a rhythmic count. The voice should be low, resonant, well-modulated in tone, and varied in inflection. It should never be monotonous and hypnotic. 11. In presenting an imagined movement, use the present participle of verbs to emphasize movement in progress, as "watch the accordion closing or being closed. " Always emphasize forces in action. 12. There are times when students are so eager to make progress that they become tense and unwittingly give voluntary help to imagined action. This can be changed only by putting the students at ease. The technique for this may be an unexpected, possibly humorous change of subject, maybe a joke — anything that will break the tenseness. 13. Once a class has become accustomed to working with imagined movement, if any voluntary movement is to be included it must be clearly labeled as such. Otherwise the student continues to imagine without 10.

urgency, and especially avoid

performing.

The teaching

of imagined movement, interdisciplinary in origin, requires a good knowledge of the appHcable sciences, the abihty to communicate,

and the abihty

to evaluate the student's response. This response in the

IMAGINED MOVEMENT: AN IDEOKINETIC FACILITATOR beginning technique.

is

innately the student's response to the teacher and the

The teacher can

231

new

follow this response by watching the student's

facial expressions.

His eyes invariably express curiosity, disbelief, lack of

understanding,

even an analysis of the teacher;

or'

or,

more

positively,

understanding, readiness to cooperate, and concentration on imagining

movement. These are all primary student-teacher reactions which must be considered. As in any teaching procedure, the willingness to learn, based on the student's trust and confidence in the teacher, is the prerequisite for successful teaching.

21 Lines-of-Movement and Imagery

One important

movement

as an ideokinetic image be correlated with the pertinent line-of-movement. The lines-of-movement derived from the first study presented in Chapter 17 locate and designate the direction of change required in the relative position of the parts of the skeletal framework to bring it into better ahgnment. Movement of any skeletal parts or part is brought about by muscle action patterned at the subcortical level of the central nervous system in response to concentration on movement in an imagined situation. Hence for imagined movement to be successful, the image and the movement which occurs in it must relate closely to that which is needed in each line-of-movement.

aspect in the use of imagined

technique for postural improvement

is

that the

The Empty In the Constructive Rest Position

The image

of the

images, contains

all

"empty

suit,"

Suit

(CRP)

which

is

actually a composite of

many

nine lines-of-movement and offers a good vehicle for

more difficult. It is used movement in your body. In your mind's

and

continuity from the simple to the

for locating

directing imagined

eye, you are the

empty suit. The suit

is

made up

of trousers with a zipper

on the

front, bell-shaped

and a zipper upper front. In addition there is a soft shirt collar inside the coat neck, an empty head, and the feet imagined as tassels. [1]* In the CRP, the trousers are supported at the knees by the cross-bar of an imaginary hanger suspended from the ceiling; the arms of the coat trouser legs, a belt, a coat with a circular neck but no collar,

on

its

rest across the front of the coat.

*The

232

The

suit is in

a disheveled condition.

[2]

boldface numbers in brackets refer to the uncaptioned drawings in Chapters 21 and 23.

LINES-OF-MOVEMENT AND IMAGERY

To

straighten out this

much wrinkled

mind's eye, the following movements as

if

suit,

you must

visualize, in

233

your

they were occurring in the empty

which is you. Now and then in the following description, parts of the empty suit are located for you by reference to a part of the body. Rest and

suit,

concentrate; do not give help to any imagined action. Inadvertently, this actual

you

movement may occur without your realizing it. Insofar as it does, the results the imagined movements are designed to promote.

forfeit

The Trousers 1

Watch the upper as its

2.

knee

is

part (thigh) of the trouser leg collapsing together

supported over the cross-bar of the hanger.

Watch the crosswise crease at the level of the rest on the empty seat of the trousers, noting

thigh joint sinking to particularly the sink-

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

234

AND MOVEMENT

ing of the inner edge of this crease. Concentrate on one trouser leg at a time. 3.

The

trouser leg

is

of the thigh joint,

midfront

is

twisted to the outside from the knee to the level which means the long crease which should be at

likewise twisted to the outside.

Watch the

trouser leg

being twisted inward across the front until the long crease is on the mid-front, that is, in line with the center of the knee and the center of the thigh joint. This imagined twisting also a very difficult

is

a very important, but

imagined movement.

4.

Watch

5.

is a tassel, made up of different lengths of thread or yarn toward the toes, shorter at the heel) which are tied together around the top at the level of the ankle joint. This circular binding is loose, allowing the inside vertical strings to fall inward away from the center of the ankle. Watch the circular binding tighten to draw the vertical threads on the inside of the tassel toward the

the bell-shaped lower trouser leg sagging together in folds

that are flimsy. Imagine their looseness.

The

foot

(long

center of the ankle joint. 6.

Repeat

7.

The

all

imagery

in the other trouser leg

seat of the trousers has

many

and

tassel.

vertical wrinkles,

making

it

look

though it were accordion-pleated. Watch these pleatlike wrinkles being smoothed away, from center outward, to produce a much broader seat. (This will not give you a broader seat; but, oft repeated, it will give you a better hip line.) Pay special attention to the center pleats which are the deepest and most firmly set, and therefore need the most smoothing outward from center. 8. Now that the seat of the pants has width and no longer pulls the trouser legs into a twisted position, watch again the sinking of the crosswise crease at the level of the thigh joint, also the trouser leg being twisted inward across the front, preparatory to closing the zipper. 9 You are now ready to watch the closing of the front zipper of the trousers. This is hampered by trouble at the lower end of the zipper where all the difficulties you have ever experienced with zippers are combined. Stay with it in your imagination until you finally see the troubles overcome and the zipper slowly sliding up the midas

two sides of the front of the trousers. movements to be visualized in the trousers, buckle sinking to rest on the back of the coat.

front to bring together the

10. Finally, to complete the

watch the

belt

The Coat 1

.

Watch

all

parts of the coat slumping as far as they car toward the

floor until all the front, sleeves included,

of the coat.

have collapsed on the back

LINES-OF-MOVEMENT AND IMAGERY 2.

235

Watch crosswise wrinkles on the back of the coat being smoothed downward. The wrinkles in the low back are being smoothed first, and then the imagined downward smoothing action progresses slowupward. In the area of the upper back the wrinkles are large, deep, and firm; they need attention with repeated downward smoothing, especially if you have a "dowager's hump" and/or a forward head. Finally, the entire back is free from wrinkles and the coat tail reaches beyond the seat of the empty trousers. There are also vertical wrinkles on the back of the coat, but only in the outer region of the shoulders. They are especially deep at the inner borders of the shoulder blades. Imagine these being smoothed outward until the coat becomes very broad shouldered. At the center back between the shoulders of the coat, however, crosswise wrinkles persist and must be smoothed downward again. Alternate the outward and downward smoothing in the upper back of the coat. Now imagine the zipper at the upper mid-front of the coat being closed to make the circular, collarless neck meet at center-front. With this zipper you run into trouble in the last inch of its upward movement. Stay with this until the difficulties are overcome and the ly

3.

4.

zipper

is

completely closed with sufficient upward force so that

downward,

the front does not sag

round-shouldered

man

as the front of the coat

on a very

often does.

The Soft Collar neck of the coat which has so many crosswise wrinkles in back that it has almost disappeared within the coat. Imagine these wrinkles being smoothed upward until the top of the collar reaches the base of the head — a long distance.

There

is

a soft,

tall collar

inside the

The Empty Head Visualize your head as a large, empty ball. In your imagination, look around at the emptiness inside, noting the great distance from side to side between the ears, and from front to back at the level of the upper jaw bone, which is on the level of the base of the skull. Above all, visualize the

emptiness of the head.

upward motion toward the head is limited to side, and to the two zippers on the front; otherwise, imagined movement is downward toward the heels, or outward In conclusion, note that

that in the soft collar

on

its

back

from center on the back of the trousers

seat,

and on the back of the outer

part only of the shoulders of the coat. If

your imagined work has been given exclusive attention, you will have

spent 20 or 30 minutes in the rest position. of your

body with the

floor will

The

size of the areas of contact

have increased, and your low back

will

be

AND MOVEMENT

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

236

closer to the floor.

If

these changes have not appeared on your

first trial

with

empty suit, look for them with repetition of the experience of being an empty suit, but never voluntarily make them. Try to become aware of, and remember the;5e areas of contact with the floor and their size, for future reference at the beginning and end of a period of rest on the floor. These are some of your best indicators of progress. At the close of the rest period get up slowly in the manner previously indicated (see p. 219); and if any area of contact with the floor should hurt, rub it with a circular motion for a few moments. the

In the Sitting Position

For the

sitting position

the empty suit needs some inside support:

a centered upright rod on which the head

sits, and (2) a crosswise rod on which the coat hangs. Sit on a chair in which the back is vertical, forms a right angle with the seat, and is low enough for your feet to rest easily on the floor. Place your "hips" as close as possible against the lower part of the chair back so that you sit on your bony rockers, the tuberosities of the ischia (see p. 34), and not on the back of your pelvis or part way up your spine. All movement imagined in the empty suit in the constructive rest position can be used in the sitting position as long as you maintain the position of the inside supports in your imagination. Thus you can ease your body any time your mind is free from attending to other things.

(1)

at the level of the shoulders

In

Standing and Walking

Most people are familiar with the scarecrows the farmers set up in their hoping they will frighten crows and other birds away. In the standing position, you, as the empty suit, need inside supports similar to the scare-crow. In the pelvis there is a level board extending crosswise, [3] half way from front to back, to support the vertical rod for the head and the

fields of grain,

crosswise rod for the shoulders of the coat.

board tends to

tip

downward

in front in

that the top of the vertical rod

which

the base of the head, not under crosswise board moving

upward

it.

it

[4]

Unfortunately, this

everybody, and supports will

[5]

be

this tipping

means

far out in front of

In your mind's eye

watch the

board in a level position (do not help), and bring the top of the vertical rod back under the center of the head. The crosswise board is supported in turn by a vertical rod under each end. These rods extend to the ground through the trouser legs. In your imagination pay attention to the inner supports; then use any imagined movements in the empty suit that appeal to you. As you walk while being an empty suit, pay no attention to the trouser legs; concentrate

on movement

head), and walk naturally.

in front to place the

in other parts of the suit (your trunk

and

LINES-OF-MOVEMENT AND IMAGERY

237

^J

Imagery to Promote the Lines-of-Movement working with imagined movement as a teaching tool, people do not respond uniformly to all images. Yet there are some images to which most people respond favorably, regardless of age, sex, activity, or occupation. Just as subjects respond differently to different images, however, they also respond differently to images which activate the various lines-of-movement. This is a rather important observation, because it leads the teacher to start with a line-of-movement in which response to imagined action is universally easy to attain, and then to progress to those where response comes more In

slowly.

The

following lines-of-movement have been arranged in the order of

imagined movement on first exposure. Under each line-of-movement images are given which have been found to be generally useful. The position or positions in which each image should be practiced is indicated after its description.

their increasing difficulty in response to

To Lengthen the Spine Downward

The

first

line-of-movement releases tightness of muscles of the back, low back. For an explanation of why persistent tightness

especially of the in these muscles

is

completely unnecessary, see

p. 63.

unbaked loaves

of dough and watch them back of the heels. (Standing) [6] 2. Imagine yourself lying on a flat toboggan so that its curved-up end presses against the back of the thighs. Watch your seat slide or lengthen 1

slide

Visualize the buttocks as

downward

downward to fit

to the

into the curve of the toboggan, thus to increase the pressure

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

238

AND MOVEMENT

end against the back of the thighs and sharpen the angle on the front between the thighs and the abdomen. (CRP) [7] 3. Visualize the trunk as a sandwich in a vertical position with a back layer, a middle layer of filling, and a front layer. Watch the back layer sliding downward. (Sitting, standing) [8] of the curved

4. Imagine each side of the pelvis as a paddle wheel, such as is used on a Mississippi steamboat, revolving to move their lower sides downward toward the heels, their upper sides upward toward the head. They are turning on an axle extending crosswise through the pelvis. The movement of the paddle wheels is somewhat like continued rotation of the pelvis to move it up in front and down in back. Watch the movement; put forth no effort. (CRP) [9]

To Widen Across the Back of the Pelvis

The second line-of-movement releases tightness of the muscles on the back of the pelvis — muscles whose tightness interferes with free flexion of the thigh joints in walking, sitting, and most activities. 1 Imagine the pelvis as a toy accordion with handles on either side and vertical pleats on the front and back. Watch the accordion being opened .

LINES-OF-MOVEMENT

AND IMAGERY

239

back to remove all pleats. (Any position, also walking) 10] Imagine the pelvis as a circular shower curtain ring with two hanging curtains on the back of the rim. Watch these curtains separating at centerback and moving aTound to the front. (Standing) [11]

wide

in

[

2.

3.

Watch the buttocks

as separate loaves of soft,

unbaked dough

flatten-

down on the floor from their own weight and flowing sideways away from each other to widen the space between them. (CRP) 4. Watch hip pockets on the back of the pelvis moving around to the front. (Any position, and walking) [12]

ing

10

From the Center of the Knee

to the Center of the

Femoral (Thigh) Joint

The third line-of-movement promotes control of the thigh close to the somewhat like the control of a whip or fishingpole at its handle. It

pelvis,

femur around the femur and femoral also helps to center the

in its socket joint.

To

and balance the muscle action

get this result such muscles as the

must take a muscles which control and move

pectineus, iliopsoas, adductor brevis, and adductor longus

stronger part in the coordinate

work

of

the thigh. 1.

Imagine a rod the size of a broomstick extending from the center of the knee deep into the center of the thigh socket. (Place a finger over this socket to help you localize it in your thinking.) You will tend to point the lower end of the stick to the outside of the socket, and fail to sink it deep enough. In your mind's eye move the lower end of the stick inward, then sink it deep into the center of the socket. Visualize an uncooked doughnut on this pole at any chosen

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

240

AND MOVEMENT

level— perhaps half the distance from the knee to the socket. The doughnut has been pulled apart on the inside. Watch it [13] being molded to close the gap on

its

inside, simultaneously

keeping

downward against the doughnut being moved slowly and carefully

the outside edge of the doughnut from sagging stick. Then watch the downward to the bottom

of the rod without destroying

its

constant attention to the inside of the doughnut to keep

it

form. Give

from

pull-

it moving downward on the inside as fast as it moves downward on the outside of the stick. (CRP) Pretend the thigh has been molded of clay but has two bad defects

ing apart and to keep

2.

has a prominent bulkiness extending from the outinward and downward on the front; also, there is a diagonal gap between it and the low front of the trunk where it should be continuous with the front of the trunk. Watch the clay being molded from the outside bulge diagonally inward and downward across the front to give a good contour to the thigh and fill in the diagonal gap between the thigh and the trunk on the front. The distortion of the contour of the thighs, often seen in the male and sometimes in the female dancer, indicates a lack of centered control at the thigh joints. No voluntary movement will change this^istortion; the movement must be visualized. (CRP) Imagine two clam shells in crosswise position, back to back, in the center of the thigh joint. Imagine the one on the front in the process of closing while the one on the back is opening. In your mind's eye keep the inner end of each clam shell touching at the back so that the opening of the one on the front looks upward; that on the back looks downward. (CRP and standing; if the back clam shell opens in standing, there will be a release of tightness in the hamstrings.)

in

its

contour.

It

side diagonally

3.

[14]

LINES-OF-MOVEMENT 4.

AND IMAGERY

241

Imagine that the round head of the femur is a ball sunk deep into the femoral socket. In your mind's eye watch the ball rotating inward so that an eye painted on its front would be turning to look at the other femoral head. Next, imagine the ball rotating so that the eye on its front looks toward your head. (CRP) Note: In most positions other than the CRP, this line-of-movement is secured by other lines-of-movement.

To Narrow the Rib-Case

The

fourth line-of-movement releases tightness of muscles between

the shoulder girdle and the spinal column, and of those muscles which

have been contracted either

to

achieve a "high chest" or in response to

"pull-up" of the trunk or "stretch up" to a taller position.

recommended for shoulder girdle and more action

this

The imagined

line-of-movement produces a more flexible

with increased range of movement

flexible ribs,

for freer breathing. 1.

Visualize the rib-case inside the shoulders as a large fat prune, ex-

tending from the base of the neck to the level of the lowest

Watch

it

wrinkle repeatedly

ders toward the center, until

2.

3.

all its

ribs.

over to shrink away from the shoul-

circumference

is

reduced

to that of

a broomstick. (Any position) [15] Imagine the rib-case as a toy accordion with handles on each side just under the arms and vertical pleats on the front and back. Watch the accordion closing inward away from the shoulders and toward the center until it is no wider than the neck. Pay particular attention to the closing movement of the pleats on the back, especially the center-back. (CRP, sitting, standing) [16] Imagine the rib-circles as tongs which can close in against the bodies of the vertebrae in back as if they were small barrels. Watch one pair after another of the tongs (rib-circles) closing in back to dig deep

As they close, they are putting more space between and the shoulders. (CRP, sitting, standing) [17] Visualize glove fingers or tight-fitting sweaters on the back part of the ribs on either side of the spine. In your mind's eye watch these covers push toward the spine just as one would push on the finger of a glove. Between each two ribs, imagine the same action as would be used to push the base of a glove finger against the crotch between fingers. Strong inward action toward the spine is needed between the ribs. (CRP) [18] into the barrels. their sides

4.

To Narrow Across the Front of the Pelvis

The

line-of-movement aids other lines-of-movement in the central part of the body in promoting a better position of the pelvis. It would seem fifth

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

242

AND MOVEMENT

II 16

would be coordinated with the work of the ihopsoas and other inner deep muscles of the thigh in response to suitable imagined movement to close inward across the front of the pelvis. that the transversaHs in particular

1.

and on the front and back. This time watch the front pleats closing together. (CRP, sitting, standing, walking) Visualize the pelvis as a basketball whose vertical opening at the center-front of the pelvis must be laced together. Watch the sides of the opening being pulled together as the lacing proceeds from below upward. (CRP, sitting, standing) [19] Visualize the ilia on either side of the pelvis as elephant ears. Watch them being folded tightly across the front of the pelvis. (CRP) [20] Imagine the ilia as wheels on an axle extending crosswise in the pelvis. The wheels slant outward at the top (front of pelvis). Watch them moving to a vertical position so that their hubs give even pressure against the axle. (CRP) [21]

Visualize the pelvis as an accordion with handles on the sides vertical pleats

2.

3.

4.

LINES-OF-MOVEMENT AND IMAGERY

243

20

21

From the Big Toe

The

sixth

to the Heel

hne-of-movement aids

in reducing pronation

and eversion

of

the foot by promoting better integration of the foot to support the thrust of

superimposed weight centered 1.

at the

ankle

joint.

Visualize the ankle joint as a hinge, Uke a door hinge, with the pin

which holds the two leaves of the hinge together extending crosswise through the ankle

joint.

One

upward into downward and

leaf of the hinge extends

the lower part of the leg; the other extends diagonally

forward into the foot. Note that the pin fails to connect the two leaves of the hinge completely because it has moved toward the other ankle joint. Watch it moving crosswise toward the outside of the ankle joint until it completely connects the leaves of the hinge. (CRP, sitting, or any position without weight on the feet) 22] Watch the big toe, as a small turtle if you wish, crawling back slowly to the inside of the heel. (Any position without weight on the [

2.

feet) 3.

4.

[23]

Imagine the foot as a duck's foot stuck in the mud. The duck's leg is centered in your leg; the webbed toes extend outward in the direction of your toes and heel. Watch the foot being pulled out of the mud, the toes leaving the mud last. (Any position without weight on the feet) [24] Imagine the internal malleolus (inner ankle bone) moving up the inside of the leg, something like a rooster's spur extending upward from the inside of the ankle joint. (Any position without weight on the feet)

[25]

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

244

Note:

When

weight

is

AND MOVEMENT

being supported on the feet or they are to be

used in walking or running, integration of the foot is encouraged more specifically by proper use of the feet through pointing them straight ahead. In standing, try to locate the center of the ankle joint in your imagination. If you are successful in doing so, the axis of weight thrust moves backward to the center of the ankle joint and causes loss of balance backis making no mistake in response to then ideally the ankle, knee, and thigh joints ideation in this instance, should be in vertical alignment in the standing position, even though this

ward.

If

the central nervous system

may never

occur with any degree of consistency.

[

23

:.i\>

To Shorten the Distance between the Mid-Front of the Pelvis

and the Twelfth Thoracic Vertebra

To help you bone.

It

marks the change

If

backward curve lumbar spine.

of the

into the forward curve of the

good,

its body end of the breast

locate the twelfth thoracic vertebra, note that

projects forward into the trunk at the level of the lower

of the thoracic spine

the relationship of the front of the pelvis to the lumbar spine were all other problems of body alignment would tend to be minor. The

LINES-OF-MOVEMENT AND IMAGERY

245

importance of the position of the pelvis in posture and movement has long been recognized, and a good deal of effort has been expended in developing ways to reduce the anteroposterior tilt of the pelvis through voluntary

These

effort.

effort's,

unfortunately, often

compound

the existing difficul-

For instance, "tucking the pelvis under" tends to reduce the forw^ard curve of the lumbar spine so that its upper part becomes a continuation of the backward curve of the thoracic spine down to the level of the third or ties.

fourth lumbar vertebra. In the person

who

has assiduously practiced

"pelvis tucking," the resulting alignment of the bodies of the vertebrae

leads to a degree of distortion (mechanical strain) in the shape of the

lumbar vertebrae and in their intervening discs. This distortion is next to impossible to improve very noticeably with any amount of work in the posture laboratory. The beauty of the slight forward curve on the surface of the low back is apparently lost forever. The adverse effect of "pelvis tucking," however, extends even beyond structural alignment. Its practice requires the voluntary contraction of the abdominal muscles and this interferes with their pattern of coordination with

all

other muscles of that area

With advance in age, muscles become less firm; and the ability to contract the abdominal muscles voluntarily begins to weaken. This weakening results in the sagging of the abdomen into a "pot belly." (see p.

1.

149).

Imagine that the lumbar spine is made up of wedge-shaped blocks, wider at the front (or top) and narrower at the back (or bottom). There are great spaces between the bases of the wedges. Watch them being pressed together to close these spaces and thus form an arch whose upper surface reaches almost to the abdominal wall. (CRP) [26] 26

Imagine the bodies of the lumbar vertebrae are the segments of a large worm with its head located at the fifth lumbar vertebra, or even hanging over the sacrum into its inside hollow. The tail segments of the worm lie in the area of the twelfth thoracic vertebra. The worm's feet rest on the floor; it is stretched out with its back flattened down. Watch it begin to work to pull its segments together in preparation for

movement, arching

its

back high

abdominal wall, but leaving

its

manner it

movement. (CRP)

integrates itself for

to almost

touch the

belly parallel with the floor. In this [27]

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

246

AND MOVEMENT

27

3.

Imagine the pelvis as a box camera with a glass front and black curtains in back. Watch the black curtains opening from the back center sideways so that the photographer can see through the front glass.

Then, in your mind's eye, watch the camera moving up in front so that it is level for taking pictures directly ahead — not on the ground. Play back and forth on these two movements: curtains separating in back; camera moving up in front. When you think the camera is right for picture taking directly ahead, walk forward naturally, concentrating on maintaining the position of the camera with open back curtains. Keep the camera directed forward in your mind's eye, so that you do not get a panoramic view in your pictures. (Standing, walking)

[28]

/

^

^--^\

\ N

/

>\

28

4.

cream cone. It tips down in front so that the ball of ice cream bulges toward the front and places pressure against the mid-front of the rim of the cone. Watch the front rim of the cone moving up to a level position to allow the ball of ice cream to fall back into place within the rim. Finally, watch a sugar plum at the level of the twelfth thoracic vertebra moving forward to

Imagine the pelvis as the rim of an

ice

the center-top of the ball of ice cream. (Standing)

[29]

LINES-OF-MOVEMENT AND IMAGERY

From the Top The top

of the Sternum to the

247

Top of the Spine

must be located for the student at the center base of the head on the skeleton, or on pictures. It can be found by placing a finger of each hand in a horizontal position under the opening of the ear and pointing inward. If the fingers were extended toward the center from each side they would meet at the center base of the head at the top of the spine. Indeed, the center base of the head is on a level with the upper jaw of the spine

bone.

This line-of-movement is especially important for the person with a forward head. Since the head sits on top the spine, the forward head indicates that the top of the spine is too far forward in relation to the rest of

Though the entire spine needs to be better balanced, the pivotal backward movement of the top of the spine is probably in the

the spine.

area for

center of the thoracic spine. 1.

Watch the top is

of the breast

bone moving up in front, or imagine it it moving upward out of the

a sliding rule and visualize one part of

other part. (CRP, sitting, standing) 2.

Visualize the

first rib circle as

[30]

a bracelet deep within the base of the

neck. First watch it closing in back, then see it moving up in front toward the head, to a vertical position if in CRP, or to a horizontal

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

248

position

if

the trunk

is

upright.

(CRP,

AND MOVEMENT

sitting, standing,

walking)

[31]

a skull cap on the back of the head. Watch

3. Visualize

it

moving over

the top of the head to reach the level of the eyebrows. (CRP, sitting, standing)

[32]

30

32

31

To Lengthen the Central Axis of the Body Upward

The body can be no taller than its height as achieved by the best balance of its skeletal framework. To try by voluntary effort to make it taller than this means more muscular work than is necessary for the upright position,

and

is

a direct interference with the balance of the anteroposterior

curves of the spine. Voluntary effort to stand posterior

tilt

of the pelvis

joints farther

back of the

and the

slant of the

tall also

increases the antero-

lower limbs to move the ankle

line of gravity.

1.

Imagine the central axis of the trunk as a sliding curtain rod, and watch it being elongated upward to raise the head to a higher position. This should be alternated with watching the spine lengthening downward in back hke a kangaroo tail. Both ideations favor better alignment of the pelvis and spine and a better position of the head.

2.

Imagine the central axis as the center pole of an umbrella, the partially open umbrella being the rib-case inside the shoulders. The bottom of the center pole (the handle of the umbrella) is within the

(Standing)

pelvis, the

[33]

handle of the umbrella, and the upper end of the umbrella The cloth of the umbrella is gathered around

pole supports the head. its

center pole at the level of the base of the neck.

To

close the

umbrella, watch the center ring to which the framework of the

umbrella attaches being moved downward, with difficulty because is

it

too small for the size of the center pole. Simultaneously, as often

LINES-OF-MOVEMENT occurs in reality

upward

when

AND IMAGERY

closing an umbrella, the center pole

as the center ring

is

249

is

moving

moving downward. (Standing,

sitting)

[34] 3.

4.

Imagine yourneck growing like an Alice-in-Wonderland neck to raise the head higher and higher. (Standing, sitting) [35] Imagine that the head is a helium-filled balloon which, being lighter than air, rises. (Sitting, standing, walking) 36] [

33

\

250

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

Ancillary Responses to Imagined

AND MOVEMENT

Movement

Given the complexity of the human body and its many interdependent it comes as no surprise that the response to an imagined movement is not hmited to change in the specific location of the imagined movement, but is complemented by ancillary responses w^hich may have farreaching effects on skeletal alignment. Thus some images, although used primarily to change particular skeletal relationships, simultaneously produce other changes of a type that occurs with other hnes-of-movement. This phenomenon is most frequently observed when imagined movement requires recoordination of muscle action rather than a relatively simple functions,

lengthening or relaxation of muscles.

These

ancillary responses

which occur with the recoordination of

muscles can be explained rather simply. Through the operation of the principle of reciprocal innervation, muscles

which are antagonists

to the

imagined movement will lengthen in proportion to the shortening of the agonists which produce the movement. Thus, some imagined movements, insofar as they are successful, lengthen some of the muscles whose lengthening has been provided for by other lines-of-movement. For instance, when images narrowing across the front of the pelvis are operant, antagonistic muscles across the back of the pelvis must lengthen in the same manner as they would in response to imagery to widen across the back of the pelvis. In view of the above, one might well question the necessity for any lengthening lines-of-movement. Experience in the posture laboratory indicates that the lengthening of tight, overdeveloped surface muscles as required in recoordination of muscle work is limited by their lack of suppleness. Hence, for satisfactory progress, special emphasis must be placed on imagined movement which will lengthen such muscles and give them more suppleness for response in reciprocal innervation. Relaxation of these

muscles does not

can and do relax

mean a loss of any of their power; it means only that they when their contraction is not needed. They become more

supple, and hence give less resistance to

The

number

movement.

is induced by the imagery used to shorten the distance between the mid-front of the pelvis and the twelfth thoracic vertebra. Any satisfactory change in skeletal alignment in this area is possible only when muscles which must lengthen in the pro-

greatest

of ancillary responses

cess of recoordination are supple

by the law

enough

to give full response, as dictated

of reciprocal innervation.

Remember, however, that the law of reciprocal innervation works in one way only; that is, contraction of agonists is accompanied by diminishing contraction of antagonists to antagonists (relaxation)

is

movement, but diminishing contraction of

not necessarily accompanied by increasing con-

LINES-OF-MOVEMENT AND IMAGERY

phenomenon

traction of agonists. This will not

explains

why

relaxation of muscles

produce a better skeletal alignment but instead places more of

the stress of weight support against the ligaments. efficiency there

must be recoordination, not

effect a better skeletal alignment

balanced work of muscles around

body

251

with

joints,

To

increase

release, of

movement

muscle action to

less stress on ligaments, more and better control of parts of the

close to the center of gravity.

A second explanation for the

ancillary responses to

imagined movement

stems from the fact that the central nervous system communicates with the muscular system throughout the body. It integrates and coordinates all

movement toward

the ideal accomplishment of man's goals, provided

man

does not interfere with the process through unfavorable voluntary action. Therefore, the subcortical patterning of neuromuscular coordination in

response to ideation can be communicated to central nervous system. Also,

constantly in response to

its

its

all

parts of the

body by the

patterning of outgoing messages changes

sensory input, which keeps the central nervous

system informed of all that is going on as movement proceeds. The central nervous system deals with man as a whole, never in parts, nor as the sum of parts.

imagined movement in the skeletal framework above and below the pelvis will be refected immediately by an ancillary response in the position of the pelvis and the lumbar spine. Often no satisfactory progress can be made in changing the alignment of the pelvis until the skeletal alignment in the rib-case and shoulders and/or in centering the femora in their sockets has also begun to improve. Finally, favorable responses to in the areas

Images for Specific Positions of the Body As stated above, many images for muscular recoordination to effect be practiced while sitting, standing, or walking. The maximal benefit from any image is attained only if there is a full awareness of the ideal skeletal alignment and a clear concept of the problems of balance in these positions. The role of imagined movement, then, is not only to produce better alignment, but also to provide increasingly greater stability in the improved alignment. Stability is invariably a function of continued practice to put firmness into the newly evolved neuromuscular skeletal realignment can

patterns of work. Sitting

A

may

on a table in the laboratory with the feet on a stool, on the floor. The position is as follows: the knees above the level of the thigh joints, knees and ankles are in the

person

sit

or on a stool with the feet

are slightly

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

252

AND MOVEMENT

plane of the thigh joints, the feet point straight ahead, the shoulders hang loosely, and the hands rest easily on the thighs.

sagittal

The movement

of sitting

down and

rising

from

sitting

seldom proceeds

evenly on the twp sides of the body. The pelvis, thighs, and knees tend to weave laterally; they seldom move through a direct path. Thus the pelvis or down from a chair goes through a spiral motion which is marked, depending on the degree of bilateral asymmetry of the skeletal alignment in the standing position (see Chapter 17). To overcome this certain element of clumsiness in standing up, the mechanics of using the legs and feet must be improved (see Chapter 22). One very reliable image toward this end is for the person to imagine that his supporting stool is positioned on a very slippery surface. The trick is to sit down and rise without pushing the stool backward and without falling forward on the face. As the individual thinks of this challenge, invariably the feet will be placed in a step position, and the trunk will lean forward by bending at the thigh joints. The individual should then actually try several times just enough of the movement to lift his weight from the stool and transfer it simultaneously to both feet. He may also be able to reduce the oscillations of the pelvis by visualizing a rough wall on either side of the pelvis, then moving into or out of the seat without scraping the sides of the as

it

moved up

slight or

pelvis against the imaginary walls.

Before discussing further imagined

movement

in the sitting position,

various skeletal features should be reviewed to support imagined move-

ment.

We know

they should front 5).

downward

the

like a rocker,

and

that the tuberosities of the ischia project

any part of the

farthest of

make

pelvis.

Their base

is

shaped

contact with the chair seat at their centers so that their

and back ends are equidistant from the seat of the chair

When

(see

Chapter

they are in the correct position, the coccyx never rests on the

chair seat.

The

thigh joints are in line with and just above the tuberosities

so that in sitting the tuberosity

and the

each side should be in the same ment and save time and energy. If the position of the front of the

thigh, knee,

sagittal it

and ankle

plane to reduce

on move-

joints

lateral

has not been done in earlier teaching,

first rib circle

and the top

of the breast

bone

should be related to the degree of backward curve in the thoracic spine, especially in its upper part. (This can be done by voluntarily rounding the back and noting how this lowers the top of the breast bone.) Any upward

movement

of the front of the first rib circle will

mean

thoracic curve. All these facts should be demonstrated

reduction of the

on a skeleton, if body and

possible; then the student should visualize their location in his

voluntarily try to center his weight

The imagined movements for centering

on the

ischial tuberosities.

of greatest importance for sitting are those

weight on the pelvic rockers, moving the

first rib circle

up

LINES-OF-MOVEMENT in front,

AND IMAGERY

253

and moving the twelfth thoracic vertebra forward toward the

center of the trunk. 1

.

Even though you have tried to center the weight on the pelvic rockers, visualize them as if they are tipped too far forward. Then watch the front end of the rockers moving upward to bring the center of (In view of the [37] muscle pulls equally strongly on both its attachments, if the ischial rockers are already in a good position the effects of the imagined movement will be transferred to the lumbar spine to produce and stabilize its forward curve.)

the rocker in contact with the chair seat. fact that contracting

Watch

3.

the front of the

first rib circle

moving upward

[38]

Watch the

twelfth thoracic vertebra (at a level just below the end of

the breast bone) moving forward to center. 4.

to a horizontal

position.

[39]

Note, in the mind's eye, the imaginary central vertical axis with the

head resting on tion

(it

top.

To

stabilize the

imaginary rod in a vertical posiit

open hand reaching from bending backward.

upward

like a sliding curtain rod

usually buckles backward), see a strong

from the front

to close

Then imagine the to raise the

head

around

it

and keep

axis lengthening

to a higher position.

[40]

AND MOVEMENT

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

254

40

When the

5.

knees tend to

apart, especially in

fall

men, watch hands

in

hip pockets moving the pockets around to the front. Also, imagine that the knees are the heads of either side extending

Watch the

back

two

horses, each with reins from

to either side of the

inside reins being shortened to pull

side of the horses

head

at

femoral sockets.

back on the inner

each knee.

Standing In using imagined

movement

location of the sacral table sits,

its

remember

the

superimposed weight

the location of weight transfer into the thighs at the front of the pelvis,

and the In

in the standing position,

on which the spine with

strategic function of the

itself,

pelvis,

the idea of the

and of

letting this

Y

amount weight

ligament on the front of each thigh

back back muscles and

of weight supported at the

sit,

will ease tightness of

joint.

of the

Y ligaments a chance to anchor the pelvis to the thighs in front enough to counteract the downward pressure at the back. Thus, the ligaments will help to balance the pelvis on the thighs (see Chapters 6 and 7). The images which follow contribute to all lines-of-movement in the central area of the body to produce better skeletal alignment in standing. It is important (1) to reduce the anteroposterior tilt of the pelvis and (2) if

give the

the person is a "pelvis tucker," to move the twelfth thoracic vertebra forward; (3) to center the weight thrust at the thigh joints; (4) to improve the postural function of the psoas major muscles; and (5) to get a better balance of the spine and better positioning of the head. Any image which disturbs the habitual relationship of the low spine, the

LINES-OF-MOVEMENT pelvis,

AND IMAGERY

255

and the proximal femora

balance backward.

forward

When

this

will invariably cause a person to lose his happens, quickly visualize a force moving

and/ or at the top of the image fails to re-establish equiHbrium (and it frequently will), take a step and then repeat the imagery. Using imagery in the standing position need not be confined to a special room or to any particular place. Any few moments when one is standing, regardless of where this may be, imagined movement can be practiced — the at the level of the twelfth thoracic vertebra

breast bone.

more

If this

often, the better.

In addition to the images given

under the discussion of lines-of-movement, the following have been found useful. 1.

Visualize an lines

Xin

the median sagittal plane of the trunk, one of

its

extending from the inside of the lower end of the breast bone

to the front

edge of the sacral

table; the other extending

from the

front of the twelfth thoracic vertebra to the inside of the pubic sym-

physis at the mid-front of the pelvis.

Watch the

lines of this

together at the top and bottom to form a vertical line in the imaginary central axis of the trunk.

concentrate on watching forward

If

movement

X closing

common

with you lose your balance, of the twelfth thoracic

vertebra and/ or a force pulling the top of the breast bone forward to stabilize the body.

2

[41]

Visualize the pelvis as a large spool with a small rod through ter opening.

The

spool

is

its

cen-

tipped so that the top of the center rod

outside in front of the body and the bottom of the rod

is

is

outside the

back of the body below the level of the pelvis. Watch the rod moving to a vertical position to coincide with the central axis of the trunk. As it moves, it will place the spool in an upright position. This image, too, will invariably result in loss of balance backward: therefore; one should try to retain balance as long as possible by imagining for-

3.

ward

acting forces as indicated in the previous image.

step,

and repeat the imagery.

Then take a

[42]

Imagine the top of the central axis far out in front of the base of the head; the bottom of the axis at the center-base of the pelvis. Watch the axis moving to an upright position as its upper end moves backward to center under the head and give it support. [43]

Walking While walking, you will not need to worry about loss of equilibrium (61). It is maintained automatically even as imagined action is changing the subcortical patterning of muscle coordination toward this end. In walking emphasize voluntarily pointing the toes straight ahead, letting the shoulders hang, and allowing the arms to swing freely.

If

the shoulders

256

FACILITATORS FOR THE IMPROVEMENT OF POSTURE

AND MOVEMENT

43 41

42

are tense or

stiff,

imagine the arms sagging out of their sockets at the shoulwould when the rubber holding

ders to dangle in space as the arms of a doll

them in place has lost its elasticity. [44] The image of the box camera is especially suitable for realignment in the pelvic area and for a smoother gait (see p. 246). Pay particular attention to opening the curtains on the back of the camera, and to taking pictures straight ahead instead of trying to get a panoramic view, as would result from horizontal rotation of the camera in walking. In the mind's eye only, the camera remains level and facing straight ahead. This imagined steadiness will tend to reduce pelvic movement to that which is a necessary reaction to change in weight support from

one limb to the other ease and balance in walking

in walking.

Another image which adds to is that of the bowl full of water. First, in the standing position, visualize the bowl moving up in front to a level position; then walk forward at your usual speed (not slowly), keeping the bowl level in the mind's eye only, so that water does not splash out the front or over the sides. [45] pelvis as a level

how

and important the utility of imagined action is in neuromuscular coordination in the upright position, its overall effect can only be rated as supplementary to that attained in the lying position — especially the constructive rest position which does not require muscle work for balance and uses props of various kinds to overcome the tight muscles which would pull parts of the body out of good Regardless of

to

improvement

alignment.

useful

LINES-OF-MOVEMENT

AND IMAGERY

257

45

44

The

practice of imagined action as a specific ideokinetic procedure,

works toward greater neuromuscular efficiency with improved skeletal alignment and concurrent change for better overall contours of the body. The changes do not come easily. The recoordination of muscle work in all movement for greater efficiency requires not only the complete understanding of the rationale for imagined movement but also irrespective of position,

the discipline of persistent practice. For

may seem

pursuit of this technique

too much bother, and they are the poorer for it, because they know the rewards inherent in its practice — persistent efficiency movement and the release of tensions.

will

in

some the

never

Part FIVE

Techniques To

Reduce Strain and Improve Neuromuscular Coordination

22 Good Mechanics in Everyday Movement

Habitually poor mechanics in the performance of

movement can

quickly

good habits of neuromuscular coordination, whether performance of competitive and professional activities or in the performance of a// daily movements. It is as important to teach good mechanics for everyday movement as for special activities, and such training should be an integral part of the educational process. Just as it is incumbent on all teachers, but especially the English teacher, to use good English in daily communication, so is it incumbent on all teachers, but particularly activity teachers, to use good mechanics in everyday movement. The example set in teaching must not, however, be restricted

inhibit or destroy

in the

to the confines of the

Good mechanics the safety of

classroom or to special teachers.

in all daily routines reduces

muscular work, increases

movement, reduces muscular and ligamentous

strain, elimi-

nates waste motion, and helps convey a sense of ease and grace of move-

ment. Poor mechanics ultimately compounds the inefficiency in one's habitual patterns of

movement

muscle action

to the point that eventually only a small

spasmed and makes movement extremely painful, if not impossible. Thus a backache is precipitated seemingly without cause. The low back muscles, are those most frequently strained, although spasm often occurs in muscles in the area of the shoulders and neck too. Backache, however, is a prevalent or effort in a daily activity can throw muscles into

rebellion

complaint

among

adults.

It

invariably

is

the culmination of continued poor

mechanics in everyday movement. One cannot expect to maintain great efficiency for any physical professional activity unless he follows principles of good mechanics in all his routine activities. A person cannot move successfully by two standards of mechanical quality — good in professional performance and poor in daily routine — without paying the price of steady accumulation of muscular strain, and perhaps pain and even impaired movement. Stooping, lifting.

261

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

262

pulling, pushing, standing, carrying,

types of everyday

movements which

and walking are some of the many

are done with greater efficiency, grace,

and safety when good mechanics are employed. What, then, are the principal factors involved in the mechanics of everyday movement? Of prime importance are the base of support for the trunk given by the legs and feet, and the movement of the trunk and its upper appendages in relation to this base. Within this framework, other factors to be considered are the alignment or integration of the trunk, the alignment of the head in relation to the trunk, the flexibility of the shoulder girdle and arms, and the freedom of movement of the thigh, knee, and ankle joints — all of which influence the ease and grace of movement. everyday movement maintaining the alignment of the trunk, as an integrated cylinder, and the head in relation to the trunk is of fundamental importance. In all forward bending of the trunk, the alignment of the spine can be maintained until the trunk reaches a 4 5 -degree angle with the thighs, but only if there is normal flexibility in the thigh joints. Further In

all

bending requires some bending or flexion in the spine, in which the trunk, ideally, will then present a long, even, but slight curve with its convexity to the back.

Backward bending of the trunk beyond a perpendicular

relationship

with its base of support is rarely needed in everyday movement. If it is attempted, the Y Hgament on the front of each thigh joint will stop the move-

ment

at these joints,

and further backward movement

will take place within

the trunk through backward bending or extension of the spine. Such extension is most likely to occur mainly in the low back and in the neck: the lumbar and cervical areas of the spine. Repeated backward extension of this type should be avoided. The most common faults in everyday movement are (1) failure to use the lower limbs to form an adequate base for support of the moving trunk; (2) substitution of

movement

in the thigh, knee,

of the synergy of failure to

and ankle

its

as a

whole

at the

Rule for Everyday

that should occur

with the beginning

femoral

at the thigh joints to

weight in relation to the

A

movement

joints; (3) interference

movement of the lower limbs

bend the trunk

distribution of

in the spine for

joints;

and

(4)

maintain the best

feet.

Movement

There is one fundamental rule which should be applied to all everyday movement: Always take a step in the direction you are going to move your body or apply its power. The step assures the follovdng: (1) a longer base over which the body can be moved forward and backward — a much larger base than that suppHed by the feet when they are side by side, (2) better ahgnment and control of the trunk in its movement whether it be forward.

GOOD

MECHANICS

IN

EVERYDAY MOVEMENT

263

backward, up, down, or sideways; and (3) force supplied mostly by the muscles of the lower limbs, with less work in the back muscles. To maintain a good alignment of the trunk with minimal muscle work in movement, good mechanics must be employed; and this means movement must take place in the proper joints, which are mainly those of the lower limbs. Otherwise, the spine all too often will be bent variously to produce the range of movement which the joints of the lower extremities are designed to produce. One often hears the warning, "Make your legs do the work." Yet even the legs can function advantageously only when good mechanics are employed in their use.

Sitting Dowri; Sitting,

and Arising from a

Sitting Position

What chair, when properly used, will give the best support for the body and simultaneously discourage poor alignment of the trunk and head? The seat of the chair should be low enough for a person's feet to rest entirely on the floor. It should be level or slightly higher in front than in back, and short enough to avoid pressure of its front edge on the back of the knee joints. Proper height of the seat positions the knees slightly higher than the thigh joints, and thus directs the weight of the thighs toward the pelvis to favor a more stable position of the pelvis. A seat which is lower at its front

edge— for example, some piano

stools

— results

in constant use of

one or both lower limbs to keep the pelvis from sliding forward. The back of the chair should be vertical; and it should meet the back of the seat, leaving only a small or no gap between the two. The height of the back makes little difference, as long as it does not interfere with the movement of the arms and trunk. The most logical support for the back of the body in sitting is at the back of the pelvis^ not at the center of the back as frequently found in the typist's chair. When the pelvis is placed against the back of the chair, its ischial tuberosities can support the trunk; in this position there is less inclination to rock the weight back on the coccyx and sacrum and thus make a good balance of the spine impossible. To sit down take a step backward toward the chair to place one foot close to or just under the chair, if possible. Then bend the trunk forward at the thigh joints, never at the waist, and aim your seat toward the angle formed by the chair seat and its back, letting the lower limbs control the movement of your body weight. If for any reason — such as lack of strength, sore leg muscles, or painful back— you need the aid of your arms, place the hands on the arms of the chair, or if there are no arms, on the sides of the chair seat, to aid in lowering the body.

not be changed during this

The

position of the feet should

(see Figure 68). After

one

is

seated,

may remain in the step position, be placed side by side a few inches or be moved slightly forward and crossed at the ankles. In all these

the feet apart,

movement

264

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

Figure 68 (A).

The trunk balanced over the feet in the step position to control movement to The sitting position, w^ith feet in step position to reduce muscular work

the sitting position. (B)

in maintaining balance as trunk

and arms move.

knees should remain upright in Hne with the thigh joints. If the knees tend to fall apart, turning the toes of the feet toward each other will brace the knees upright; although this muscle-saving position does not look very graceful and tends to be difficult to maintain for persons who foot positions the

habitually turn their toes outward.

Since the thigh joints are rotary joints, the knees

may be

crossed

if

does not interfere with even pressure of the pelvis on the chair seat.

this It is

the tendency, however, to cross that thigh which will favor an increase of

lumbar spine which may already be a part of body alignment. If a person is aware that one side of the pelvis is more prominent laterally than the other, he probably should cross only the thigh opposite the lateral pelvic prominence so that he will not exaggerate the existing deviations from good alignment. The size of the any

lateral deviation of the

one's pattern of

thighs can also interfere with easy crossing of the knees.

If

the lower leg

of the top knee does not hang easily and closely to the other leg,

not to cross the knees at

all.

Men

it is

better

often place the ankle of one limb on the

let the knees fall apart. These positions feel more comfortable because of tight muscles on the outside of the thighs and across

knee of the other, or they

the back of the pelvis. It is not advisable to place both feet in a position on the floor lateral to the knees for, if continued, it adds muscular and ligamentous strain on the knees and tends to promote uneven pressure of the pelvis on the chair seat and to bend the spine laterally. Some people start lowering themselves to the sitting position by bending first at

the knees

— an

interference with the natural synergy of

of the lower limbs. In so doing, they look as

if

movement

they will eventually sHde

GOOD MECHANICS off the front of the chair seat since the

(instead of the pelvic base) are

the person

ment

how

his joints

aimed

IN

EVERYDAY MOVEMENT

265

back of the coccyx and the sacrum at the chair seat. Instead of tehing

should work, the teacher should describe move-

of the pelvis toward the chair seat in such a

way

as to elicit "natural"

action in the joints of the lower limbs.

Many

people wobble laterally as they sit down, spiraling the movement of the base of the trunk so that one side of the seat reaches the chair seat

ahead of the other. This

is

a

common

fault,

which usually

results

from the

difference in the relation of the lower limbs to the center of the sacral table.

To coordinate the muscles more efficiently, imagine you are moving bebetween two rough walls (see p. 252). While maintaining this picture in the mind's eye, simply

sit

To get up from the

down

naturally.

chair, reverse the

above order of

sitting

down.

First

place the feet in a step position; then, maintaining both feet on the floor,

bend the trunk forward at the thigh joints (not the waist) and stand upright between the imaginary walls. The weight during this movement is maintained on both feet and in readiness to move forward immediately. The whole process could be described as walking out of the chair between the imaginary rough walls.

Sitting at a

The most common

faults

Desk or Work Table

when working

at a desk, table, or

bench are

the following: (1) chair too far from the desk, (2) bending forward in the

spine instead of in the thigh joints, and (3) feet resting side by side, or some-

times curled around the chair legs, instead of in a step position. In sitting

on a high

stool for

work

at a high table, as in

many

laboratories, the rungs

of the stool are invariably used to support the feet. Support should be pro-

vided for the feet in front of the legs of the stool at the proper height, but

seldom is. When the chair is close enough to the work table, the trunk can be bent forward at the thigh joints without disturbing the resting posi-

it

The step position of the feet gives further stability to position. Thus movement for better use of the arms and hands,

tion of the pelvis.

the pelvic

or turning of the trunk, can occur mainly at the thigh joints with minimal distortion in the trunk;

and any movement

for

more favorable use

eyes will require only slight nodding or turning of the head.

When

of the typing,

the typewriter should be low enough for the lower arms, wrists, and hands to

be in a horizontal position for their work. Otherwise they tend

the shoulders to place the hands in a

Even when work

more favorable

to

lift

position.

is continued over a period of time in the sitting posimuscular fatigue can be greatly reduced when the body is given proper support in relationship to the working surface, and good mechanics are employed in the movement of the trunk and arms.

tion,

266

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION Specific Problems of

Movement

Pushing and Pulling Objects

The more nearly

one's bones are aligned to take the force of either

pushing or pulling, and the better the base over which the body moves, the easier the task. The center of the height and the weight of the object

be pushed or pulled determines the amount of bend in the thigh, knee, and ankle joints, and hence the degree to which the center of gravity of the

to

Figure 69 (A). Pushing with the center of gravity of the body in line with the center of gravity of the object. (B)

Opening a heavy door.

GOOD MECHANICS

IN

EVERYDAY MOVEMENT

B.

A. Figure 70 (A). Opening a

267

wdndow

in

back of a radiator. (B) Reaching upward.

body must be lowered. Applying power too high on an object will mean force does not travel through the arms and trunk to the legs, and the trunk will tend to bend backward in the lumbar area of the spine, thus bringing unnecessary strain on the low back. If, as power is applied to an object, it

should

move

suddenly, the step position prevents loss of equilibrium.

drawer close to the floor, kneeling on one knee establishes a good base and lowers the center of gravity of the body closer to the level of the drawer. In opening a heavy door, the use of the In opening or closing a bureau

step position

makes the

task not only easier but also safer (see Figure

69).

Opening

a

Window

in

Back of a Radiator or Other Object

Placing the body close to a it

considerably easier.

When

wdndow makes a radiator

is

the task of raising or lowering

in the

way,

try turning the

body

sideways to the window and placing one foot on the radiator. Keep the other foot as close to the radiator as possible, then move the window (see Figure 70 A). The step position helps to avoid injury to the low back. If there is nothing between you and the window, face slightly sideways close to the

window, place the

feet in step position,

and proceed with the

task.

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

268

Reaching Upward

upward to place an object on or take it off a high shelf, stand away.from the shelf and place the feet in the step position. The trunk and arms should slant slightly forward to maintain alignment of the trunk during the task (see Figure 70B). If one stands too close to, or under the shelf, there is no way to prevent backward bending of the trunk in the low back, with resulting strain and sometimes injury — especially if the object to be moved is heavy, or if the position must be maintained during work, as in painting or cleaning a ceiling. In reaching

just a little

Stooping Stooping to reach or pick up something at varying distances beyond easy reach of the arms takes place repeatedly throughout the day. Stooping with the knees straight, feet side by side, and bending in the spine is a common mistake which both is awkward and requires more work than necessary.

To pick up something from the

you should place the feet in a step Remember that an object picked while walking or running can be up without loss of stride or waste of energy when good mechanics in movement are used and the very same mechanics in the lower limbs can save time and energy in stooping from position at the side of

and

floor,

close to the object.

the standing position. In tying a shoe, try sitting or kneeling

be in a step will be need

first.

In either case, the feet should

position. In sitting, kneeling, or standing to tie a shoe, there

some degree

bend

reduced in proportion to the flexibility of the shoulder girdle and the degree of bending in the joints of the lower limbs. Too much bending in the thoracic spine for

of

in the spine, but this

is

backward curve tends to body alignment. Squatting to pick up an object is a waste of time and energy (see Figure 71). To the extent that the trunk is lowered, it must be raised again. Moreover, if the trunk remains in a vertical position as one rises from squatting, the hamstrings will not help in the work of coming to the upright position (see pp. 151, 152). Only when the line of gravity of the body falls in front of the thigh joints will the hamstrings engage in this work. To avoid unnecessary work in any one set of muscles, it is better to distribute the work of returning to the upright position between the extensors of the back, thighs, and knees. This distribution will occur only if, in stooping, the trunk bends forward simultaneously with bending of the thigh, knee, and ankle joints. The degree of bend will differ in the two limbs because of the differ-

occurs

all

too frequently, especially

be exaggerated

if its

natural

in one's habitual pattern of

ing position of the feet in relation to the trunk.

We often stoop to put in or recover something from

a tote bag or a suit-

GOOD

MECHANICS

IN

EVERYDAY MOVEMENT

269

.>»-

Figure 71

(A).

Stooping to pick up an object, with the Hne of gravity of the body as close to

the object as possible. (B) Squatting with the trunk vertical to pick

up an

object.

(Compare

with A.)

case.

The same

principles apply to this

movement

as to other stooping, but

bend needed in the and ankle joints. If the suitcase is resting on a chair, you will bend the spine; a slight forward slant of the trunk through its

the height of the tote bag will determine the degree of thigh, knee,

not need to flexion

on the thighs should provide

all

the

movement

necessary.

Carrying an Object Objects

may be

carried by one suspended arm, by holding the object

against the side of the pelvis or against the front of the body, by a strap

over the shoulder opposite to or on the side of the object, or by resting the

on the back. The "backpack" is frequently used by hikers and inworkman who must carry a large, heavy object without the help of another person. In this situation the trunk is flexed on the thighs to center the weight over the lower limbs. As a rule, each person wdll tend to carry an object in a manner which represents an exaggeration of his habitual deviations from efficient body alignment. Except when weight is supported on the back, the trunk should be maintained in the upright position during carrying, and the weight should be shifted frequently from object

variably by a

side to side. If

one knows which side of the pelvis tends

erally (especially

there

is

to

be more prominent

lat-

greater indentation of the waistline on that

and whether the lumbar spine deviates laterally in the opposite direcsafe to advise carrying an object with the suspended arm which opposite to the lateral prominence of the pelvis and on the same side as

side), tion, is

if

it is

270

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

Then as the trunk maintained upright, muscular contraction in proportion to the weight being supported by the suspended arm will occur between the low spine the lateral deviation in the lumbar spine (see Figure 72).

is

Thus lateral bending of the low spine prominent pelvis is avoided. As a general rule, it is easier to carry an object on the side of lateral prominence of the pelvis, since the muscles on the side of the convexity of a lateral curve in the lumbar spine are stronger. This pull, however, will encourage an exaggeration of the existing deviations in the central area of one's body. Unfortunately, our daily activities always tend to increase any inefficient alignment of the skeletal framework. If an object is carried by a strap over one shoulder, adjustments of the spine for its balance above the lumbar region tend to be highly individual (see p. 200). Whichever shoulder is used for the strap, however, the carrier must avoid raising it above the free shoulder. In dancing, the male, and less frequently the female, dancer must receive and lift the weight of another dancer. Timing and coordination of the movement of the dancers is extremely important, but it is equally important that the dancer who receives and lifts another dancer should have his feet in the step position and should lift the dancer close to his body. Unless the dance is to convey a sense of awkwardness, strain, and danger of injury (as we so often see it in daily life), there is really no reason the and the

laterally

prominent

pelvis.

to the side opposite the laterally

Figure 72. Carrying a weight with the suspended laterally

with

its

convexity on the

left. If

left

arm when

the lumbar spine curves

the upright position of the trunk

location of muscle contraction to anchor the weight to the pelvis occurs

cavity of the lateral curve

between the spine and the

pelvis.

is

maintained, the

on the side of the con-

GOOD

MECHANICS

IN

EVERYDAY MOVEMENT

271

choreographer should not choreograph the dance so that the body can move in conformity with physical laws, at least some of the time, and especially

when such movement

will not detract

from the message of the dance.

Movement on

Stair Steps

Going upstairs requires forward bending of the trunk at the thigh joints forward foot as one lifts the

(not the waistline) to shift the weight over the

movement should always occur in the thigh joints, not in the Though the ball of the foot is first to reach a higher stairstep, the whole foot should rest on the stairstep as the body weight is lifted, for this body. This spine.

position gives better leverage in the use of the foot. In running upstairs,

of course, the weight

When

is

supported entirely on the balls of the

going downstairs,

if

feet.

the steps are not deep enough from front to

back for the foot to point straight ahead, it is safer to face slightly sideways and likewise place the feet slightly sidewise in relation to the direction of movement. If a railing is at one side of the stairs, it is always safer to have one hand on it, especially if fatigued, so that balance can be maintained if momentarily lost. Whenever loss of strength in leg muscles, great soreness from overuse of muscles when not in condition, or a lame back makes mounting stairs difficult, one can always assist the muscular work of the legs by placing the hand or hands on the thigh of the limb which must lift the weight, and pressing down on it. Even then, however, the alignment of the trunk should be maintained by adequate bending at the thigh joints.

The Basic Postures Sleeping

The mattress

bed should be firm enough to give only slightly to the If it is too soft, plywood should be placed under it. Any mattress which readily conforms to the contours of the body cannot be good for it. Sleeping on the face or on the back with the legs extended pulls the pelvis downward in front, due to the action of the Y ligament on the front of a

contours of the body.

of the thigh joints (see p. 66). it

can be changed by

sleep

comes

to turn

first

If this is

one's habitual

way

assuming the side-lying position each night,

finally in this position. Also,

it is

When

until

possible to condition oneself

completely from one side to the other as position

the night.

of going to sleep,

is

changed during

sleeping on the side, a pillow should be used to maintain

the position of the head in alignment with the trunk.

The shoulders should

sag forward, and the arms should rest in any comfortable position in front of the trunk

— but

never under the head.

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

272

Standing Standing

is,

for

most people, one of the most

tain over a period of time (see p. 183). at attention for too long a

be

for the circulation.

difficult positions to

main-

The soldier who faints while standing

time illustrates

how

detrimental the position can

On the other hand, standing first on

one limb, then on mus-

the other, with the pelvis thrust far sideways promotes inefficiency of cle coordination as the

change

is

made from one

distorted position to an-

other.

How, then, can one relieve muscle strain and change the pressure of muscles on blood vessels in the lower limbs without resorting to distorted positions? First, distribute the weight evenly between the feet, preferably in a slight step position.

one

shift

the weight slowly, but not entirely, from

foot to the other while trying to avoid

of the pelvis. If

ward

is

cussed.

one foot

is

If

movement can

marked change

slightly to the front, the shift

not especially noticeable; and

the fonvard

this

Then

if

one

is

engaged

in the position

forward or backin conversation,

pass for greater interest in the topic being dis-

one has had the experience of using imagined action

in the body,

technique also can be used to bring change throughout the body which

muscle tension, and yet be too small a movement to be movement can simultaneously improve body alignment. It is the general experience of those who have improved their body alignment through the use of imagined movement will help release

noticeable to others. Moreover, imagined

that this technique helps to

make

standing

much

less fatiguing.

Walking In walking, the feet should be directed straight ahead and weight should be transferred through the center-forward part of the foot, not through the inside of the big toe joint. This movement has been stressed repeatedly throughout this text because the detrimental effects of poor mechanics in the use of the feet extend throughout the entire body. Walking with the feet turned out necessarily increases rotary

movement

of the pelvis in

all

somewhat differently in each person. If, as in sitting down one imagines walking between rough walls no farther apart than the width of the pelvis, the mechanics of the entire movement, especially of the pelvis, will be improved. Also, one can imagine the pelvis as a bowl full of water, not to be spilled during movement. By trying to hold the bowl level in the mind's eye only, the coordination of muscle work can be improved at the pelvis where the turn-out of the feet has its origin.

directions, but

(see p. 252),

When

the length of the stride

is

increased, the

added length

is

attained

mainly through horizontal rotation of the pelvis to move it forward on the side of the forward-moving limb. Uneven rotary movement of the pelvis in walking will always occur in conformity with the alignment and neuro-

GOOD

MECHANICS

IN

EVERYDAY MOVEMENT

273

muscular habits in the central part of the body, and it will differ with each person. Efforts to produce voluntarily what one might consider "enticing" movement of the pelvis in walking invariably results in awkward and uneven movement. Such attempts are frequently seen in television advertisements.

one move forward first when starting to walk? Interwhich is less reliable in weight support, the one on the side of lateral prominence of the pelvis (see p. 201). On the other hand, some persons establish their equilibrium more through muscle work than through mechanical adjustments to deviations from good body alignment, and these persons would not be so likely to "step out" from the promi-

Which

estingly,

nent

leg does

it is

usually the one

side.

From

the foregoing discussion

it is

evident that

many

factors both affect

and are affected by one's everyday movement. It requires a little ingenuity to use good mechanics in everyday movement in view of the variation of purposes and combinations of movement. Indeed, movement is affected by both internal and external considerations. There is little doubt, however, that poor mechanics in the use of the lower limbs has a great deal to do with increasing inefficiency of muscle coordination — especially in promoting muscle strain in the low back which, sooner or later, is likely to precipitate trouble in this area, a complaint already

all

too prevalent in our adult popu-

lation.

In order to establish tions of the

body

good mechanics

in

everyday movement and posimust concentrate on moving

as a matter of habit, a person

correctly over a period of time. This

is

the only

way

to

overcome poor me-

chanics of movement. However, the time and thought given to good mechanics brings with

it

the reward of easier, quicker, and safer daily move-

ment, with delay, or perhaps elimination, of muscle aches and pains that tend to come with increasing age, and all too often even in youth.

23 Voluntary

Movement

The movement techniques recommended here for teaching neuromuscombine voluntary movement with concentration

cular recoordination

on imagined action in the body. These techniques are designed only to promote more efficient coordination of muscle action throughout the body as movement of a part of the body is performed. They do not increase endurance or muscular strength as conditioning exercises do. The muscular recoordination occurring with the performance of any of these movement techniques, while concentrating on imagined action, is invaria'bly too extensive and complex to permit accurate analysis. The first noticeable response in the performer is one of awareness of increased flexibility and ease in his body. Such awareness arises more quickly in some than it does in others, and it varies in degree from person to person. It is ultimately related to the degree of expertise with which the movement techniques are performed and the success in simultaneous concentration on imagined action. The teacher must emphasize repeatedly that the performance of voluntary movement while concentrating on imagined action is extremely difficult, and perfection is seldom if ever achieved. Yet the improvement m joint flexibility and bodily ease which are attainable through these techniques makes them well worth the effort. The movements which are described in this chapter have been chosen from a large number designed and used by the author, and they represent those found to be most effective in teaching posture and solving problems of movement. They have been developed to meet the needs of a majority of people, regardless of their daily and special activities. They may seem simple, and many of them are when they are performed without special regard to their manner of performance. It must be strongly emphasized, however, that these movement techniques have little or no value when they are performed hastily or haphazardly, without concentration on the imagery essential to their success.

274

VOLUNTARY MOVEMENT

275

it should be obvious why every person who is interested in improving his posture must also give attention to his habits in the daily use of his body. Continued poor mechanics in positions and movements, espe-

By now,

work, can be constant barriers neuromuscular habits.

cially in relation to one's

lishing

more

efficient

Principles to

When

Guide the Use of Voluntary Movement Techniques

voluntary

movement

is

following principles should guide 1.

The pattern

used to improve body alignment, the performance.

its

of the voluntary

must be understood

2.

to progress in estab-

movement,

in order to picture

it

its

location

and

direction,

clearly in the mind's eye.

be moved and the joints involved, moving part whether for weight support or for movement of the body, possible mistakes committed in performing the movement, and the reason for the movement from the standpoint of desired change in body alignment all contribute to understanding the movement itself. The clearer the concept of the movement, the better the subcortical programming of it. The voluntary movement must be confined to the part which is supposed to be moved. This may require repeated experimentation,

The

structural design of the part to

the

main function

with

full

of the

attention being given at

good example of

first to

this is shoulder-tip lifting

the

movement

toward the

itself.

A

ceiling in the

constructive rest position (CRP) (see p. 283). The pattern of the movement must be learned first so that it can be performed automatically and the mind can be freed for concentration on appropriate imagery.

Only then

will the student

be able

to

improve the efficiency of muscle

coordination as needed to stabilize the body for the movement. 3.

The range

of

movement

is

invariably very small, sometimes scarcely

noticeable. Quality, not quantity, of

the standards set for

movement

movement

is

sought. Meeting

requires efficient coordination of

muscle action; it is valueless to continue the movement when old habits of muscle coordination remain in control. One often learns to associate and detect faults of movement wdth the imagined action being used, even before there is any marked evidence of these faults. An example of this is thigh flexion in the CRP, in which faults are associated with what is happening to the image of the plate glass and marble (see p. 291). A teacher skilled in the art of palpation can detect relaxation in the muscles of the lower back as it occurs through reciprocal innervation of agonists and antagonists, and can determine before actual movement occurs whether the coordination

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

276

of muscles

ratory to 4.

is

being changed in response to the imagery in use prepa-

movement.

Movement must be performed

repeatedly in order to establish firm

habits in irnproved neuromuscular coordination.

6.

There must be complete rest betw^een attempts to perform the movement. This is absolutely necessary (a) to assess the contrast between no work and the degree of effort expended in the movement, and (b) to determine the effectiveness of the movement in producing greater bodily comfort and increased flexibility. Imagined movement should be used both before and during voluntary movement. There is always a tendency to start the actual movement too soon, once it is understood, without taking time to concentrate first on the imagery being used. The sequence after the movement has been learned is (a) complete rest, (b) imagined action, (c) slow movement with continued concentration on imagery,

7.

(d) sudden release of effort, and (e) sensing the change, if any. Voluntary movement must be slow in order to allow time for imagined action to exert its influence on the subcortical patterning of

5.

the

work

of agonists, antagonists, synergists,

and

stabilizers.

The

movement, the greater the probability that it will be performed by the very neuromuscular habits one is trying to change toward increased efficiency. Imagined action during voluntary movement of any part or parts of the body is invariably located in the trunk. Its direction is often faster the

8.

in the opposite direction of the distortion the voluntary will

produce

in the trunk.

Voluntary

The

movement

Movement

with Imagery

description of each of the techniques discussed in this chapter will

include (1) the position of the body, (2) the purpose of the voluntary movement, (3) the procedure in its performance, (4) suggested imagery, and (5)

comments

as

needed.

When

necessary, the pertinent anatomical facts

will also be given. The teacher must be careful to provide all factual information needed for an accurate, clear mental picture of the movement before any attempt to perform the movement is made. The imagined action found to be best suited to promote increased efficiency of the neuromuscular coordination, patterned for the movement at the subcortical level, will be described. Finally, the kind of mistakes which are apt to occur with the voluntary performance of the various movements, and which are often too subtle for easy detection, will be indicated.

entering into the design of the

movement

VOLUNTARY MOVEMENT

277

Respiration

The inhalation phase of respiration is a muscular function. The diaphragm contracts td lengthen the thoracic area, and the ribs rotate outward and upward to increase the circumference of the rib-case (see Chapter 11). The exhalation phase is at first facilitated by the pull of gravity on the ribs and the

elasticity of both their costal cartilages and the lung tissue; then continued by muscular contraction which increases as expiration is forcefully prolonged.

it

is

always influenced by the position of the body and its postural alignment. The better the alignment of the trunk and head, regardless Breathing

is

movement, the more efficient the muscle action of breathing. The person with a hollow low back (lordosis) and an increased anteroposterior tilt of the pelvis uses the front half of the diaphragm more than the back half, and the movement of breathing occurs disproportionately more in lifting the chest and in forward movement of the upper abdomen. Such abdominal movement is sometimes wrongly attributed to strong use of the diaphragm; in fact, it reflects poor trunk alignment and correspondof position or

ingly inefficient coordination of

all

the muscles engaged in breathing.

The significance of good breathing mechanics varies with the type and amount of activity. It is particularly important for anyone engaging in strenuous activity, such as sports and the dance, and in drama and singing. Some voice teachers advise breathing "to the back"; others, "to the front"; and still

The

others advise centered breathing.

last

conforms wdth the structure

and function of the diaphragm. Its efficiency depends, however, on the alignment of the trunk and the head. Even when breathing is ideally centered in the trunk, it will be slightly more noticeable on the front of the abdominal area, as the downward excursion of the diaphragm places pressure on the abdominal organs. Anyone who has watched the development of a sprinter or distance runner over a period of to throw the head back, breathe more shallowly, however, the alignment

years has probably noticed

how

at first

he tends

break the alignment of the trunk and head, and especially at the end of a race. As he improves,

of the trunk and head improves correspondingly be good, even to the end of the race. Although the struggle of breathing persists, it becomes more effective. A flexible rib-case, loose shoulders, and a good position of the head in relation to the trunk help

and continues

to

the runner's respiration, just as they aid anyone's breathing, particularly that of those

who engage

Respiration

is

in strenuous activities.

employed

in

many

of the

movement techniques used

in the posture laboratory. In order for the student to use

he must

it

intelligently,

generally understand the skeletal structure involved in breathing,

the structure of the diaphragm, and

its

movement. Since the diaphragm

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

278

is

complicated in both structure and function,

we

shall simplify its operation

here by likening it to a dome-shaped piston with centered control as it moves up and down in a cylinder. The trunk is the cylinder; the diaphragm is the piston whose outer circumference is attached to the inner circumference of the lower, very irregularly shaped opening of the rib-case. The movement in breathing occurs through depressing the upward curve of its dome during inspiration and allowing it to return to its normal height during expiration.

Hissing Hissing

a technique of exhalation in which resistance

is

is

given to the

outflow of air by placing the tongue against the upper front teeth and forcing the air past this resistance. for exhalation, especially

No

when

Thus more muscular

the hiss

is

prolonged as

effort

much

is

required

as possible.

by bending the trunk or by pressing the arms against the rib-case. Both bring undesirable muscle action, and hence one must guard against them. The hiss should not be explosive; it should be slow and lazy. Its sound is similar to either of the following: a prolonged sibilant sound like a continued ''ssssss, " or the sound of escaping air from a tire or steam from a teakettle. A "big" breath should not be taken in preparation for hissing; this action means only that some of the air is expelled before muscle action is required, and thus time is wasted. The value of hissing lies in the muscle work of closing the rib-case downward and inward by contraction of the muscles which are opponents to those which are active in maintaining a high, tense, and inflexible rib-case. This technique of expiration will finally engage the abdominal muscles in an ideal way, providing no bending takes place assistance should be given

in the spine.

Hissing

may be performed with the body in any position. When it accom-

panies prescribed movements, to be given later, the position of the body will

be indicated.

may be substituted for hissing, though neither be as effective in promoting flexibility in the shoulder girdle and ribcase. Buzzing like a bee, or buzzing a tune, such as "Yankee Doodle," as long as possible on one breath are other possible substitutes for hissing and are somewhat better than whistling and singing. Whistling or singing

will

Position

I.

Purpose.

To

Constructive rest position (CRP). increase flexibility of the shoulder girdle and rib-case.

Procedure. Note the degree of ease of the arms as they rest on the front and whether there is need of "holding" them so they do not slide

of the chest

off the chest.

Then place both arms

to

reach easily beyond the head and

VOLUNTARY MOVEMENT to rest

on the

floor.

The elbows may remain bent

The position of the arms should not be forced. Take an ordinary breath and hiss as long as

as

needed

279

for comfort.

possible without bending

the thoracic spine. Rest. Repeat this hissing four to eight times, resting

between each attempt and trying to hiss a little longer each time. Breathe naturally at least two times between each effort. Return the arms across the chest, and note whether they rest more comfortably and without being held in place. If not, try the procedure again. Imagery. Visualize the rib-case as an elongated balloon collapsing

ward toward a central

line in its entire length during

Comments. Many people cannot maintain the the front of the rib-case in

arms overhead invariably

CRP

each period of

position of the

in-

hissing.

arms across

without holding them there. Hissing with

results in

an easy

rest position for the arms.

Most

students use the technique at the beginning of a laboratory class before the instruction of the day of

work on

is

started

and

at the

beginning of each period

their posture outside the laboratory.

Position

II.

Sit as tall as possible

with comfort, with feet supported and

the hands resting easily on the thighs.

Purpose.

To

increase the flexibility of the shoulders and ribs, and to

improve the trunk alignment (see Chapter

17).

Procedure. Use imagined action to promote a better trunk alignment with increased ease while maintaining a vertical position of the imaginary central vertical axis (see pp. 253, 254).

Next, try the technique of shoulder shrugging as a means of sensing the shoulder girdle. Lift the shoulder tips toward the eyes; then immediately drop them without bending the imaginary axis. One shrug should be enough to sense the effort involved in lifting the shoulders.

flexibility of

While maintaining the imaginary central vertical following sequence of

movement:

(1) lift

axis,

perform the

and drop the shoulder

tips to

note

the effort needed, (2) raise the arms easily above the head and hold them there, (3) hiss as long as possible (with arms up) on one breath only, (4)

drop the hands on the thighs without allowing the central vertical axis to bend, and (5) shrug the shoulders to compare the effort with that used in the first shrugging. Repeat the movement sequence with hissing three to five times, noting by means of the shoulder shrugging any difference in the effort used.

Imagery. While raising the arms above the head and

when dropping

the arms, concentrate as hard as possible on the imaginary upright axis.

This imagery will help to maintain the stability of the spine as a weight-

supporting structure, regardless of the location or

movement

of the arms.

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

280

Pretend that the trunk

is

a long balloon collapsing inwardly around the

central vertical axis as hissing proceeds, or use any

row the

image designed

to nar-

rib-case (see p. 241).

Comments. To gain a clear sense of flexibility of the shoulders, emphasis must be placed on dropping them without muscular control immediately after they have been lifted toward the eyes. There is often a tendency to move the shoulders up and down several times without letting them drop completely and to move the shoulders toward the back of the head instead of toward the eyes. Centered Breathing

The CRP should be used

Position.

breathing. Later any position

may be

for the first practice of centered

used; in fact

it

can be practiced well

while walking. Purpose.

The

when one

tion

practice of centered breathing helps to (1) promote relaxa-

is

extremely tired and generally tense following certain

types of work; (2) reduce emotional stress and tensions; (3) aid in "calming

down"

its

accompanying muscular

after exciting activity; (4) discourage

the habit of shallow, chest breathing; and (5) promote a better alignment of the trunk.

Procedure. Breathe naturally without trying to change voluntarily the rate

and depth of breathing. These

will take care of themselves.

Imagery. Imagined action varies somewhat, but thinking

is

always

centered in the trunk. 1.

Imagine the diaphragm as a piston in the cylindrical trunk moving up and down a few inches in the center of the trunk at about the level

end of the breast bone. Watch the piston moving upward toward the head during exhalation; downward toward the pelvis during inhalation. Let the rate and depth of the breathing occur as it will without voluntary control. If a deep breath is taken, as for sighing, watch the piston moving farther downward toward the

of the

pelvis until exhalation begins. 2.

Imagine a long thermometer containing red mercury in the central axis of the trunk. Watch the red mercury move upward toward the head in exhalation and downward toward the pelvis during inhalation.

3.

Imagine the central vertical axis as a rod with a close-fitting ring on it at the level of the lower end of the breast bone. Watch the ring moving upward on the rod toward the head during expiration— but with difficulty because it is so tight fitting, then downward toward

VOLUNTARY MOVEMENT the pelvis in inspiration.

4.

The more

difficulty

one can imagine

movement of the ring, the better the results will be. The following image is more easily conceived in the position (see p. 000). Imagine that the trunk

is

281

in the

prone-lying

divided into a front

and back half by a plate glass which is parallel to the resting surface During inspiration, watch air moving down the trunk back of the plate glass to fill imaginary lungs, or balloons, located in the seat of the pelvis to elongate them to the heels. This will mean a slow, controlled intake of air as one tries to avoid forward movement of the chest against the supporting surface. Next hiss the air for the body.

out as lazily as possible, but without effort to prolong the

hiss.

Take

a few natural breaths; then repeat the process. Contrary to the pro-

cedure for centered breathing described above, one tries to breathe down the back and to control the rate and depth of the breathing. This position and method of breathing are especially helpful for the

person

who

habitually holds his chest high and experiences

diffi-

culty in breathing in strenuous activity.

Head

Flexion on the Spine

Position.

CRP.

Purpose.

To

release suboccipital muscle tension

gration of the trunk during this

and

to

promote

inte-

movement.

Procedure I. Flex the head on the spine without lifting it (the head) from its supporting surface. This is accomplished by rotating the head in a sagittal plane on a horizontal axis from ear to ear to move the chin into the front of the neck.

Imagery. As the head

is

rotated forward slowly as far as possible, the

upward pressure against the arms. This movement distorts the trunk alignment. To promote better action of muscles which maintain trunk integration, watch the chest sink downward chest will tend to rise to produce

toward the supporting surface as the head is slowly rotated forward. At the completion of head flexion, do not place it in its former position; just quit work and let the head rest where it will. This is most important. Rest completely; then try the movement again. Start with visualizing the chest sinking; then flex the head and continue concentrating on the sinking chest. This movement with its imagery should be practiced until the chest no longer rises in response to the movement of the head. Sometimes muscles at the base of the skull remain tight, and one can feel their resistance to head flexion. They can be loosened with the use of one or more of the following images.

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

282

1.

Imagine that the skull is divided into a front and back half, but the back half has slipped downward so that its top part is lower than the top of the front half. Watch the back half moving upward until the

two halves are even

at the top of the skull. (46)

46

2.

Imagine the action in the collar of the empty suit (see p. 235). It has slumped downward into wrinkles within the back of the coat collar. Watch it being smoothed upward until it reaches the base of the

3.

Imagine a skull cap on the back of the head being moved forward until it reaches the eyebrows (see p. 248).

skull.

Procedure

11.

When you

are successful in flexing the head on the spine

the head from

without

lifting

there

muscular control of

is

its its

supporting surface, continue flexion until

minimal lifting. where it will. The

entire weight, but with

Then

stop the effort suddenly, and let the head rest sudden release of effort enables one to note the extent of upward movement of the chest, that is, the extent to which head flexion sufficient to gain control of its weight has distorted trunk alignment. Its greatest distortion comes at the moment of gaining complete control of the weight of the head, and this is the time when one must concentrate strongly on watching the chest sink. The shoulders will also tighten at this time, but this tightening can be lessened with the image of the rib-case as an accordion closing inward (see p. 241).

Comments. The location of flexion of the head on the spine should be determined by the student by placing a finger of each hand in a horizontal position under each ear, between the upper back of the jaw bone and the mastoid process. If he elongates the fingers in the imagination to meet each other at the center base of the skull, he will have located both the atlantooccipital joint

The

rising chest

and the horizontal is

axis

on which the head turns. it by the sterno-

a typical reaction to the pull on

cleidomastoid muscles working to lift the head. The tightening of the shoulders typically accompanies a great many of our more difficult movements.

Experience indicates that emphasis on flexion, or rolling the head forward, until its weight is supported by muscles, is more likely to produce

VOLUNTARY MOVEMENT and retain the type as

it is

of

movement

283

desired: continued flexion of the

Hfted very shghtly. Flexion of the head on the spine

is

head performed

by very deep muscles — the right and left rectus capitis lateralis, rectus capitis anterior, and longus capitis. The contraction of these muscles as synergists must be maintained to counteract the extension of the head on the spine by the sternocleidomastoid muscles as they contract to lift the head. Emphasis in teaching on rolling or flexing the head on the spine retains the action of the deep anterior muscles. Shoulder Tips Moving Forward or Upward Toward the Eyes Position its

I.

CRP,

in

which the elbows must

rest

on the chest closer

to

central line than the tips of the shoulders (acromial processes) to prevent

the weight of the arms from automatically producing undesired contraction in the pectoralis

to

major muscles.

Purpose. To increase the freedom and flexibility of the shoulders and promote primary control of the movement of the upper extremities close

to the trunk, that

is,

at the shoulder girdle.

Move the tips of the shoulders forward (toward the ceiling abduct the shoulder blades on the back, without any action in the pectoralis major muscles. The movement may be confined to one shoulder only. Procedure.

in

CRP)

to

Most people tend

to

move

the shoulder tips forward by contracting

the pectoralis major muscles which form the front boundary of the pits as

they attach the upper

arm

arm

to the front of the rib-case. Since these

muscles are not attached to any part of the shoulder girdle, they are not opponents of the invariably tense muscles on the back between the shoulder blades and the base of the head and the spine as far thoracic vertebra.

To

down

as the twelfth

release the tightness in these muscles

between the

shoulder blades and spine through reciprocal innervation, the work of

moving the shoulder blades forward away from the spine must be performed by their antagonists, primarily the serratus anterior and pectoralis minor muscles. The serratus anterior muscles are attached to the vertebral border of each shoulder blade and pass between it and the rib-case to attach to the front of the rib-case. The pectoralis minor muscles attach to the coracoid process of each shoulder blade and to the front of the rib-case. Learning to eliminate contraction of the pectoralis major muscle as moves forward is not always easy. The following experimentation may help. Place the fingers of one hand on the pectoralis major the shoulder tip

muscle of the opposite arm, that

is,

on the front of the arm

pit at the outer

part of the front of the rib-case. Lift the shoulder tip forward and note any

change

in the firmness of the

muscle beneath the

fingers.

It

should soften

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

284

becomes firmer and bulges forward. It may help to imagine the testing fingers elongating downward to pass between the side of the rib-case and the shoulder before starting the movement, then continuing to elongate during the shoulder movement. In other words, as the shoulder tip is lifted, one imagines the fingers moving toward the back of the body. It may also help if one locates the joint for the movement at the top of the breast bone on the front. The shoulder girdle pivots from here in its movement. Sometimes the student learns the proper technique more quickly by and

sink;

if it

contracts,

it

raising both shoulder tips very slowly forward simultaneously, while con-

centrating on watching the chest sinking in the opposite direction. Shrug-

ging the shoulders, as ness, or dislike, also

is

sometimes done

may produce

to express lack of interest, aloof-

the right technique.

Hissing can be added to shoulder tip lifting as follows. Start hissing

then move the shoulders very slowly forward trying to move them no more than an inch by the time the breath gives out. Only a slight movement, if it is well done, will produce appreciable comfort in the shoulders, but if the movement is carried too far it can produce reactionary tightening (stretch reflex response) in the muscles that have been released in the first part of the movement through reciprocal innervation. first;

The student

often

is

more

successful

if

the teacher's finger tips are

placed on the ribs just inside the vertebral border of the shoulder blade is being moved forward and pressed gently toward the spinal column. The pressure of the teacher's finger tips helps the student to localize and give direction to the imagined movement.

that

Imagery. Imagined action should be used both before and during movement. It must be designed to close the ribs inward and downward while the imaginary central axis remains straight. The rib-case may be pictured as a closing accordion, a shrinking prune, or a closing umbrella (see pp. 241, 249). Watching the front of the rib-case sinking against its back also helps create effective muscular coordination.

Comments. The upper extremity may be compared to a whip or a lariat which is moved by force applied to its handle. In the upper extremity the force of the one-joint muscles between the shoulder girdle and the trunk is transferred through two- and multi-joint muscles to the finger tips. Those muscles effectively harmonize the movement of all the joints of the upper extremity. This action, along with the increased comfort of the shoulders

and neck, makes flexibility and efficiency of muscle action on the shoulder worth working for. Sometimes a person tries to move the shoulder tips too far forward. In doing so, he may pull muscles on the back between the shoulders and trunk girdle well

VOLUNTARY MOVEMENT

285

before their suppleness has been increased sufficiently to take the strain.

This "overmovement" then elicits the stretch reflex, and the muscles on the back tighten against the pull. Here, as in other movement techniques for posture

the

improvement,

it is

quahty of neuromuscular coordination, not

amount of muscle action, which is being sought. Moving the shoulder tips forward diametrically opposes the

direction

frequently prescribed in kinesiology books for the "correction" of round shoulders and round upper back. Nevertheless, we have found this exercise to

be helpful for the following reasons. 1.

The shoulder

girdle

is

a hanging and sitting structure, situated over

It hangs by muscles attached to a higher level column and to the base of the skull back of the atlantooccipital joint; it is superimposed over the top of the rib-case, and sits on the breast bone at the front. It is not a weight-supporting structure responsible for the position of any other skeletal parts.

the top of the rib-case.

of the spinal

2.

Engineering principles, as well as the principles of muscle function, suggest that in dealing with round shoulders, one must the alignment of the skeletal parts which give

3.

The shoulder

it

consider

first

support.

girdle articulates with the trunk only

on the front

the rib-case at either side of the top of the breast bone.

Any

of

forceful

adduction of the shoulder blades pulls these articulations, and mus-

respond automatically by contracting to protect the joints. pectoral muscles eventually respond to stretching, whether by an outside force or by self-adduction of the shoulder blades, by contracting against the pull (stretch reflex). This stretching procedure implies that it is tightness of the pectoral muscles which causes round cles

4.

The

shoulders. Contrary to this, the pectorals and their fascial sheaths probably shorten to accommodate their length to the distance between their origin and insertion — a distance which is shortened when

the shoulders are "round." 5.

To

exercise the adductors of the shoulders to "hold"

posedly good position

ment

of the

is

framework

somewhat

them

like trying to correct

of a building

by pulling on

its

in a sup-

poor align-

roof with guy

ropes.

Practice of forward

movement

of the shoulder girdle, as here advised,

alignment of the skeletal framework except accompanying imagined movement improves it. Flexible shoulders, however, will contribute to the effectiveness of other procedures with the various lines-of-movement designed to improve the alignment of the will not contribute to a better

insofar as

skeletal supports of the shoulder girdle.

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286

Position

II.

an upright position with the weight centered on

Sitting in

the tuberosities of the ischia, with the feet supported, and with the hands resting easily

Purpose.

movement

on the

thighs.

To promote and maintain the

integration of the trunk during

of the shoulder girdle.

Procedure. First concentrate on the imagery suggested to produce integration of the trunk with greater ease in the sitting position (see pp. 252, 253). Move the shoulder tips upward toward the eyes (or forward),

but not so far as possible. Next

moving the shoulder

let

the shoulders hang.

upward and forward

Then

start hissing,

forward only) during the remainder of the hissing expiration. At the end of the hissing suddenly let the shoulders drop to fall where they may. Their resting position will be as good as the coordinated action of the musculature of the shoulder girdle and the trunk will allow. tips

(or

Imagery. Sometimes the image of sitting on a one-legged stool helps

weight of the body on the tuberosities of the ischia. In the parts of the trunk must be tied inward and downward to the central axis, which balances over the leg of the stool. to center the

mind's eye,

all

Whether the shoulder

tips are

toward the eyes, the movement

moved forward, will

upward upward and

or forward and

tend to pull the ribs

bend the central vertical axis of the trunk to make it convex toward the back. To avoid this, while moving the shoulders, imagine a hand reaching inward from the front at the level of the lower end of the breast bone to close tightly around the axis and stabilize it against bending (see p. 253). Try to reach back far enough from the front with the imagined hand, and be sure

to close

Comments.

strongly around the axis.

it

If

one seems

ischial tuberosities,

to sit

what value

with the weight centered through the

lies in visualizing

the tuberosities as rockers

ends (see p. 253 )? If weight is centered on the tuberosities, the imagined action will produce a better balance of the forward curve of the lumbar spine, mainly through increased contraction of the psoas major muscles. These muscles are of strategic importance both to postural alignment and to movement. But their most efficient coordination cannot be established by voluntary movement, and there is doubt that anyone senses the work of these muscles apart from all other pro-

moving up

at their front

prioceptive reports that reach the consciousness. Furthermore, according to the

more recent

the cortex, or

if

studies, impulses

they do,

we remain

from the sensory spindles do not reach unconscious of them (59).

VOLUNTARY MOVEMENT

287

Realignment of the Forward Head

A forward head is one that trunk. Instead,

it is

no longer aligns with the

vertical axis of the

displaced forward, and the depth of both the cervical

and thoracic curves tends to be greater than normal. The head is extended (tipped backward) on the cervical spine, and this position may result in suboccipital tension which is often marked in the deep muscles. In the CRP, the spine of the student with a forward head contacts the floor at about the level of the fifth and sixth thoracic vertebrae (ideally this should be near the second or third thoracic), and the first thoracic vertebra is much too far forward from the floor. The chin points toward the ceiling instead of down toward the front of the rib-case. Since the head is the uppermost part of the skeletal framework, its position "on top" can be improved only if the entire structure underneath is brought into better alignment for its support. Yet some misguided techniques of teaching begin realignment of the body at the head. This training cannot be supported by either anatomy or mechanics. To place and hold the head in a supposedly "good" position by using such admonitions as "up and forward" is as fallacious as placing and holding the shoulder girdle in a supposedly "good" position. On the contrary, whatever improves the alignment of other skeletal parts below the head will also improve the position of the head. Position

Purpose.

I.

CRP

with a small pillow under the head, not under the neck.

To promote

a central position of the head over the trunk.

Procedure and Imagery. The sequence of techniques of movement with imagery which has proven to be effective in promoting a better position of the head follows. Those that have been discussed in detail previously will be named only. First, work toward increasing the flexibility of the rib-case and shoulder girdle. No satisfactory change of the spinal column is possible without this flexibility and it will bring with it a change for the better in the position of the pelvis. To change the alignment below the pelvis too, employ imagery which promotes the line-of-movement from the knee to the center of femoral joint (see pp. 239, 240). It may further be necessary to use imagery to

widen across the back

its

front (see pp. 242, 243), both of

and to narrow the distance across which promote better centering of the

of the pelvis

femoral heads in their sockets. After this preliminary work,

all

of

which may not always be necessary,

tightness of back muscles should be released as

much

as possible. In addi-

smoothing crosswise wrinkles out of the back of the coat "empty suit" (see p. 235), (1) imagine the spine growing long like a kangaroo tail, starting very wide at the top in the area of the coccyx and

tion to imagining in the

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

288

watch a chain made up of very heavy Unks resting on the floor at the center of the back and moving downward toward the heels; or (3) imagine a bicycle chain moving down the back from the first thoracic vertebra to circle around the lower end of the trunk and move up the front to circle the top of the rib-case and continue again down the back. Suboccipital tension may be released next by using the following imagery, some of which has already been described: (1) the skull cap (see p. 248); (2) moving the back half of the skull upward (see p. 282); (3) imagining muscles at the base of the skull in back as sculptor's clay which is being sgraped off from the center sideways, until the base of the skull is clean as far forward as the junction of the head with the spine; and finally (4) watching a fountain in the center of the empty head shooting upward in a vertical stream to the top of the skull where it breaks and sacrum;

runs

(2)

down

the interior surface of the skull.

head forward, with very slight Hfting (as described between the various imagined actions, always imagining the chest sinking simultaneously. This exercise helps one to determine whether suboccipital muscle tightness has been reduced. Perhaps the key area for needed change, in addition to the pelvic area, is the upper part of the thoracic spine and the first few rib circles. The first rib may be visualized as a bracelet with its closing in back (see p. 247). First watch the bracelet closing with difficulty; then watch it move backward to rest on the floor, then upward in front toward the head so that it is vertical with the floor. These imagined movements may be repeated with the next three rib circles, though the first is the most important. They should be followed by the movement of head flexion on the spine. Try

above)

rolling the

now and

Position

II.

then,

Sitting or standing.

First, voluntarily assume the best position body in the sitting position, moving the head back to center over the trunk. Then, while maintaining the central axis in the mind's eye, begin imagined action to release the muscle strain throughout the body. Finally, watch the first rib circle moving upward in front to a horizontal position. Remember that this rib circle is very small and must be visualized deep inside the base of the neck. Return attention to the central vertical axis, and stabilize it at the center (see p. 253); this is as important as moving the first rib circle up in front.

Procedure and Imagery.

possible of the entire

Comments. The problem of the forward head is difficult to overcome it involves change in the alignment of all the weight-supporting structures below it. Furthermore, it involves change in habits of everyday movement, especially that of bending the spine (a habit encouraged by because

VOLUNTARY MOVEMENT the often heard admonition to "bend at the waist"

—a

289

directive that should

be completely discarded — instead of the thigh joints, as should be done. Changing such habits requires determination to think about and practice good muscular coordination as often as possible each day. To move the head forw^ard at any time, the trunk as a whole should be flexed on the thighs so that the spine itself need not be bent. Thus the head is moved forward only because its base of support, the top of the spine, is

moved

forward. Finally, the only necessary

flexion

on the

eyes.

(If

first

movement

of the

head

is its

vertebra, the atlas, as needed for the best use of the

the eyes do not have normal vision, they must be corrected with

lenses insofar as possible.)

Thigh Flexion

CRP. This is the most favorable position for successful training abdominal muscles to work within their resting length, which is the distance between the lower rim of the rib-case and the upper rim of the pelvis when they are in efficient alignment. Supine lying with the legs extended pulls the pelvis down in front and elongates the abdominal muscles, making it impossible to achieve adequate thigh flexion (see Chapter 16). Position.

of the

Purpose.

To promote

resting length all

efficiency of their coordination with

other muscles in the central area of the body.

Procedure. is

contraction of the abdominal muscles within their

and thus improve the

tion of

It is

as important for the thigh to

be flexed

efficiently as

it

work effectively to stabilize the integrathe trunk during movement. The technique of thigh flexion must

for the

abdominal muscles

be learned

to

first.

In trying to understand the concept of control of the

movement

of the

thigh close to the pelvis, try thinking of the thigh as a fishing pole, the

lower leg as the string attached to the end of the pole at the center of the knee, and the foot as a fish with its tail at the toes. The fish is pulled out of the water by applying power to the handle of the fishing pole. [47]

The mistakes that are most likely to occur with thigh flexion should be determined by the student through experimentation, described here in relation to flexion of the left thigh.

To get

of thigh flexion, first flex the left thigh to floor, the toes leaving the floor last. is

flexed, note

whether

the pelvis on the floor, erally

there

it

is

shifts to

the

a general idea of the

lift

movement

the foot completely from the

Let the foot hang. Next, as the thigh

weight changes the location of the pressure of and if so, in what direction pressure moves. Genits

left side

and toward the heel; anatomically speaking,

pelvic rotation to the left -and increased anteroposterior

tilt,

slightly

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

290

more on the

left side

—a

natural reaction to the increased pressure of the

weight of the flexed thigh on the

left pelvis.

47

To discover by palpation the occurs with

left

location of undesired muscle

thigh flexion, the fingers of the student's right

work which hand should

be placed on the back of the right thigh on the upper part of the right hamstrings close to the tuberosity of the ischium where they are attached.

Before flexion of the thigh begins, these muscles should be relatively If

soft.

they are not, switch immediately to the imagery for the line-of-movement

from the knee

239, 240). As the

thigh

is

flexed, the hamstrings of the right thigh tend to tighten in

most people

to

brace the right thigh against the pelvis and thus stabilize

position against

to the thigh joint (see pp.

its

left

left thigh. When this happens, muscular being done by an appendage of the trunk (the right thigh) when it

the pull of the weight of the flexing

work

is

should be done by the abdominal muscles of the trunk.

The work

in the abdominal muscles can also be tested by resting the hand on the abdomen. These muscles should be relatively soft in CRP, since their only action should be that which occurs with breathing. As the left thigh is flexed, however, the abdominal muscles tighten — but they should not bulge forward in a curve if they work within their resting length, which they seldom do. Thus when the thigh is flexed correctly in the CRP, it involves work in the abdominal muscles but not in the hamleft

strings of the resting limb.

Finally, to note

whether the thigh

is

moving

in the sagittal plane of

should be flexed as far as comfortable without bending the spine. Most people move the knee toward the outside of the trunk, the thigh joint,

it

because of excessive muscular hypertonus on the outside of the thigh. This deviation in direction of movement indicates a lack of centered control

VOLUNTARY MOVEMENT of the thigh close to the pelvis.

It

291

sometimes helps to visualize the thigh which is the handle of the knife. [48]

as a knife blade folding into the trunk,

Through

this

experimentation the student learns that in ideal (and

very rare) thigh flexion, whether single or double, the thigh moves in the

plane of the thigh

sagittal

leg is

and

foot

joint,

the hamstrings do not contract, the lower

hang under the control

of gravity,

muscle power

for

movement

applied to the thigh close to the pelvis, and the position of the pelvis

is

maintained by strong contraction of the abdominal muscles acting within their resting length.

Of

all

the factors listed above, the student should

first

concentrate on

flexion of the thigh without tightness in the hamstrings of the other limb.

This coordination must become automatic before progress can be made.

Imagery. The average student will need far more than one image to help him to overcome the various mistakes of thigh flexion. In order to

move

the thigh in the sagittal plane, one must maintain the head of the

femur, in the mind's eye, in close contact with the inside of the socket as flexed. To understand this image, visualize the head of the deep socket, by studying the structure of the joint either on a skeleton or in anatomical pictures (see Figure 5A). Another useful image

the thigh thigh in

is

is

its

that of the thigh fitted diagonally against the lower trunk, as in

china dolls (see

p.

some

257). Visualize the inside of the thigh pressing firmly

against the trunk so that no gap occurs

between the two during thigh

flexion.

The image

of the plate glass, which relates to the entire trunk, has be most effective in laboratory experience in promoting contraction of the abdominal muscles within their resting length. The imaginary plate glass divides the trunk into front and back halves, is parallel with the floor, and is as long and as wide as the trunk without the shoulder girdle. A fist-size marble rests on the plate glass at the level of the lower

proved

to

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

292

end

of the breast bone.

[49]

Flexion of the

press the left corner of the plate glass

left thigh, for

downward toward

example, will

the floor, and the

comer. Hence, the student must concentrate on maintaining the level position of the plate glass so the marble will not roll, while slowly and steadily trying to flex the thigh, that is, to start pulhng the fish (the foot) out of the water. One soon learns to interpret mistakes made in the movement of thigh flexion, as described above, in terms of what is happening to the plate glass and the marble.

marble

will roll to this

The abdominal muscles must never be tightened voluntarily before or during the movement of thigh flexion, for this action will completely defeat the purpose of the exercise. Their use must be determined subcortically in response to the

image of maintaining the

level plate glass (or

any other

appropriate image) on which the person concentrates. They should start to contract

from their resting length and continue their contraction

to the

it is needed to stabilize the relation of the pelvis to the rib-case. Avoid sudden or fast movement, for this does not give the imagined action time to produce change in neuromuscular coordination in the area. It takes long practice and many repetitions of thigh flexion, with strong concentration on imagery, to build efficiency in the abdominal muscles. Once their coordination with other muscles is improved, however, it is of lifelong value, both in maintaining efficiency of skeletal alignment and in preventing the onset of muscle pain and strain, especially in the low back, pelvis, and lower limbs. Thigh flexion, single or double, may be accompanied by hissing. If so, as the student hisses, he uses imagery preparatory to thigh flexion. Then toward the end of a hiss, on one breath, he slowly and slightly flexes his

extent

thigh.

When

the pattern of bilateral skeletal alignment in the central part of

the body shows well-defined lateral deviation in opposite directions in the lumbar spine and pelvis, the thigh on the side of the laterally prominent pelvis

is

usually the one in

which

flexion should be practiced

frequently. This thigh tends to be farther from the central pelvis

and hence more

difficult to flex.

Indeed, the student

is

Hne

more

of the

often aware

VOLUNTARY MOVEMENT of this difficulty through previous

the difference in the fort at the pelvis

movement

and upper

movement

experience. While w^alking,

of the limbs, as

thighs,

is

293

vs^ell

as in the

muscular

often quite evident. In this case,

ef-

more

time should be spent flexing the thigh on the side of the laterally prominent pelvis (which is often accompanied by greater indentation of the waist line

on the same

side)

skeletal alignment as

both to reduce the bilateral difference in the central

much

as possible, and, especially, to learn

how

to

keep the asymmetrical alignment from becoming worse with advancing age.

Double Thigh Flexion. To flex both thighs simultaneously is much more difficult than flexing only one thigh, because it requires far more abdominal work. As in single thigh flexion, but even more significantly here, the student must refrain from voluntary contraction of the abdominal muscles. The same imagery may be used here as was applied for single thigh flexion. If the imagery is effective and if the muscle action for flexion is efficient, the back muscles in the region of the lumbar spine will soften — in fact, before

movement

is

started.

The

position of the pelvis wdll not change,

it will press more heavily on the floor. Double thigh flexion in CRP, when its performance

although

the foregoing procedure,

is

is

in accord

with

quite effective in rescuing the natural forward

curve of the lumbar spine from the straightening effect of ardent "pelvis As previously stated, however, permanent change in the form of

tucking."

the lumbar vertebrae and their intervertebral discs, resulting from changed weight thrust through them, often makes complete recovery of the natural forward curve of this section of the spine impossible. In the posture laboratory double thigh flexion with imagery is often alternated with the use of imagery only, which

One

is

located in the area of the

image is that of the lumbar spine either as wedges or as a segmented worm, its segments being the vertebrae (see p. 245). If this imagined action is successful the back muscles will soften on either side of the low spine, and the spine will curve forward slightly from the supporting surface, becoming more flexible and subject to easy movement by the teacher's hand. On the other hand, the back muscles may tighten if the person voluntarily "helps" the image — and if so, good results cannot be expected. Another image is that of visualizing the lumbar spine as a large muscle, something like the muscle on the front of "Mr. World's" upper arm. Watch this muscle contract to shorten and bulge forward toward the abdominal wall. lumbar

spine.

useful

Comments. One

of the faults of thigh flexion

attention of the teacher

is

which may escape the

that of voluntarily adducting the thigh to bring

head closer to the inner border of its socket. In this situation, the teacher must emphasize again that only imagined action will recoordinate muscle action to center the head of the femur in its socket. its

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

294

Another

fault

which seems

to require

repeated warning

is

that of

holding a flexed position of the foot during thigh flexion instead of letting it

hang.

CRP may seem like an easy movement. When performed with the aim of securing work of the abdominal muscles within their resting length, however, it becomes extremely difficult. It is not taught in our posture laboratory until the student is experienced in the use of imagined action, has made improvement in skeletal alignment, and has had experience in voluntary movement techniques for the head and Flexion of the thigh in

it is

the shoulder girdle.

There are various reasons for inefficient work of the abdominal muscles. is poor posture, of whatever type it may be. Another is the habit of voluntarily tightening the abdominal muscles. There probably are few people who have not been told at some point to "pull in the abdomen," usually wrongly called the "stomach muscles." Sometimes the practice of tightening the abdominal muscles has been so deeply ingrained in a person's behavior that the muscles remain tense even in CRP when there is no movement and no reason for action of the abdominal muscles except as they cooperate in normal breathing. Still another reason for inefficient use of the abdominal muscles is the repeated practice of exercises which require the abdominal muscles to start their contraction from an elongated position. This occurs with all exercises which start from supine lying with the legs extended. Such exercises appear among practically all physical fitness and conditioning programs. They require either flexion of the trunk on the thighs, in which

One

the flexion partakes of the nature of the "curl-up", or flexion of the ex-

tendedlower limbs on the trunk (see Figure 73). In either case, the starting and the design of the exercise is such that efficient neuromuscular coordination becomes impossible. Bad habits of movement are built by such exercises, and these carry over into awkward movement of the body in daily hfe. But this is only one of the faults of such exercises. Their repeated practice results in a forward position of the head and a rounded back, which is invariably accompanied by round shoulders. The contour of the body, as seen from the side during the "curl-up" and similar exercises, indicates the deviation in the alignment of the head and trunk toward which the repetition of the movement is building. Nor can increased flexibility of the joints be claimed for such exercises. On the contrary, flexibility is decreased in proportion to the imbalance they position

build in the weight-supporting Class

I

levers, especially those of the spinal

column (see Chapter 16). Lastly, the practice of these types of exercises promotes habits of poor body mechanics. Good movement of the body cannot be expected when poor movement is practiced persistently as a part of a fitness or conditioning program.

VOLUNTARY MOVEMENT

295

Figure 73 (A). The curl-up. (B) Flexion of the extended limbs on the trunk.

It is

why

indeed

difficult to

understand

why

such exercises are advised and

they continue to appear in kinesiology texts and physical fitness

When the design of bones and joints, the principles of muscle and the laws of mechanics are heeded, any imaginative person can design exercises which either promote integration (efficient alignment) programs. function,

of the trunk, or are not detrimental to

its

alignment, as

movement

occurs

in the various parts of the body.

Movement of the Feet and Ankles Many of the problems of the feet and

ankles have their origin in poor and the inefficient neuromuscular habits which accompany it. As the body above the feet gains improved alignment, foot problems quite often disappear, even to the extent that they require no special attention. When special attention is necessary, the objectives which must be kept in mind are (1) centering weight through the ankle joints, and (2) good mechanics in the use of the feet. skeletal alignment

Centering weight at the ankle people, the line of gravity joint

and the

axis of

the ankle joint. Only

falls in

weight thrust

when

joint. In

the standing position of most

a coronal plane in front of the ankle is,

the pelvis

is

therefore, in front of the center of persistently in an efficient position

and transfer of body weight can weight be centered through all improvement of skeletal alignment contributes the ankle joints and an efficient use of the feet.

for the support

the ankle joints. Hence, to

balance at

it passes through the center have a clear concept of the structure and

In order to shift the axis of weight so that of the ankle joints,

one must

first

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

296

anatomical features of the joint (see Chapter

The image which has somewhat unique in that

9).

been used successfully for centering the weight is involves merely concentration on visualizing the location

it

of the joint, that

is,

of the center

a search in the mind's eye for the center. This mental

effort results, among other things, in a realignment of the lower limbs toward a more vertical position. The most notable phenomenon associated with these changes is a loss of balance backward, resulting from the inability to produce immediately the neuromuscular coordination in the pelvis, proximal thighs, and lumbar spine which will maintain balance as weight centers through the ankle joints. When balance is lost, try concentrating immediately on such imagery as a force moving the top of the breast bone or the twelfth thoracic vertebra forward, or a hand stabilizing the central vertical axis (see p. 255). These images will promote the muscle coordination needed to gain equilibrium of the body. You will always be able to regain balance by taking a step backward, and, with constant repetition of the experience, you will improve the alignment of the entire body. Practice, however, will never bring complete success in maintaining equiHbrium when thinking is centered at the ankle joints, because the prevailing direction of movement in our daily activities is forward, and this movement favors the tendency to increase the anteroposterior tilt of the pelvis. (The belt buckle leads.) Furthermore, the sway of the body in standing consistently moves the axis of weight thrust in various directions

in relation to the center of the ankle joint.

Mechanics in the use of the feet. In standing and while walking, the be directed straight ahead. Thus, when weight is centered at the ankle joint and the toes are directed straight ahead, a sagittal plane should bisect the ankle joint and foot. The path of weight transfer through the foot in walking and running lies in this sagittal plane. toes should

Flexion (Dorsi-flexion) of the Foot Position.

knee

CRP, with one foot supported at the Achilles tendon on the Each knee must lie in the sagittal plane of its own

of the other limb.

thigh joint;

it

must not sag inward or outward.

Purpose. To balance muscle action on either side of the ankle joint while maintaining control of the thigh close to the pelvis.

The control of each thigh should be brought close to the by the use of imagery before any movement of the foot is tried. Such images promote the line-of-movement from the center of the knee to the center of the thigh joint (see pp. 239-241). They eliminate activity in the hamstrings that might help to maintain the position of either limb. Procedure.

pelvis

VOLUNTARY MOVEMENT Flex the supported foot as far as possible, thinking of

which

it

297

as a hinge

closes evenly (see p. 243), while maintaining, through imagery, the

Then suddenly

control of the thigh near the pelvis.

continuing concentration on control at the thigh successful, there will

the foot flexion

is

release the foot while

technique is any time, even when

joint. If this

be no action in the hamstrings

at

released.

In the sitting position with the knees crossed, the hanging ankle can

be flexed

similarly, again using the

image of the hinge

in action.

Imagery. The value of ankle flexion depends on the degree of success of

imagery

in

producing a more efficient coordination of muscles engaged

movement while

in the

the ankle

is

the thigh

flexed, visualize

it

controlled close to the pelvis. Before

is

which holds the two between the inner and outer ankle

as a hinge with the pin

leaves together extending crosswise

bones (the malleoH), but projecting

to the inside.

Thus, the outside of the

moving toward the bone until it the outer ankle completely connects leaves of the hinge. Then, as you slowly flex the ankle, imagine a continued force pressing on the inner end of the pin to keep it in place during movement. leaves of the hinge are not connected. Imagine the pin

Before the effort of flexion

head of the femur

of the

control as flexion

is

is

suddenly stopped in CRP, visualize control

at the socket,

then continue concentrating on

this

CRP, suddenly released. For example, eagle's claw gripping the head of the femur strongly the socket

in

may be imagined as an from below.

move

If

the eagle's claw

as the foot flexion

strings

be contracting

is

to

is

in sufficient control, the

knee

will not

released suddenly, and at no time will the ham-

maintain the position of the knee in the

sagittal

plane of the thigh socket. Since an inefficient position of the foot

is

invariably accompanied by

pronation, imagined force on the inside of the ankle can be directed

upward

outward as in the pin of the hinge. In this instance, during flexion one can imagine a spur, like a rooster's spur, growing upward from the inner ankle bone, or the ankle bone itself moving up the inside of the leg (see p. 243). Either direction of force, if actually appHed, would reduce pronation of the foot. Another imagined movement which aids flexibility of the ankle is that of moving a large grapefruit, in the mind's eye, from the knee downward

on the inside of the

leg, or

into the heel to give the heel a ing) while the foot

is

marked bulge

held in a flexed position.

(the lower leg being a stock-

Or a sword may be

visualized

moving out of the center of the heel, with the center of the leg as its The image of either the grapefruit or the sword, both of which may be envisioned while the foot is at rest in the CRP, reduces tightness as

sheath.

of the calf muscles.

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

298

Flexion of the Little Toes Position. Sitting with as

good alignment of the trunk as possible without

strain.

Purpose.

To promote

action in the short muscles on the bottom of the

foot.

Procedure. Flex or dig the

little

toes into the

of tendons on the front of the ankle in the tibialis anticus

movement, and

it

ground without any action

joint, action in

on the outer front side of the

requires

some patience

the big toe, or action

leg.

to learn

it.

This

not a typical

is

When

the

movement

muscle activity on the bottom of the foot can be seen and felt. The foot remains on the floor; sometimes the big toe must be held down as one tries to learn the movement. Once it is learned, it may be performed with the hanging foot when the knees are crossed, or with the toes picking on a string (such as a banjo string) stretched between the legs of a chair is

right, the

placed in the right apposition to the

foot.

Comments. This movement of the foot increases its flexibility and thus helps it to adjust to ground surfaces more efficiently, but it must be coupled with careful attention to mechanics in the use of the foot in everyday movement in order to reduce strain on ligaments as much as possible.

Rotation of the Foot Position. Sitting

Purpose. the ankle

To

with feet supported, or in CRP.

increase the efficiency of coordination of muscles around

joint.

Procedure.

The

foot

is

moved in when

the leg crossed over the other

a very small circle as sitting, or as

the Achilles tendon on the opposite knee in cling should

the leg

CRP. The

be alternated.

imaginary screw projecting upward

ly,

hangs from supported at

it

direction of the cir-

Imagery. Thinking should be centered at the ankle

and turning

is

in the center of the

joint.

Watch an

from the top bone of the foot (the talus)

lower surface of the

tibia.

Comments. It is very difficult to perform the circling movement smoothand most people tend to move the foot in too large a circle. The value

of the

movement hes

in the very small circling with thinking centered in

the ankle joint. In order to visualize the center of the ankle joint success-

study its structure on a skeleton or in pictures. The movement occurs between the bones of the foot with very slight flexion and extension, but no lateral movement, of the ankle joint.

fully,

VOLUNTARY MOVEMENT

Lateral

299

Weight Transfer

Position. Standing with the weight evenly distributed on the feet, the ankles in the sagittal plane of the femoral joints, and the toes pointing straight ahead. The hands should rest Hghtly on a support such as the back of a chair or a table in front of the body.

Purpose. To promote increased muscle control on the inside of the and thigh joint.

pelvis

Procedure. Very slowly try to transfer the weight to the foot on the

move sideways weight transfer. The foot from which the weight is being transferred slowly extends at the ankle joint as weight is moved from it, the toes leaving the floor last, or not at all, as effort is put forth to keep the pelvis from moving sideways. side of the pelvic prominence without allowing the pelvis to

in the direction of

is between rough walls which it would movement. Try, in the imagination, to maintain the between these walls and not pressing against one of them during

Imagery. Imagine that the pelvis hit in

pelvis

any

lateral

weight transfer.

Comments. This movement was designed to eliminate a clicking noise accompanied sometimes by a rolling bulge of muscle on the outside of the ilium when walking, running, or leaping. Both the noise and bulge tend to occur on the side of the pelvis which is more prominent laterally in the standing position. The weight is transferred to the limb on the side of the clicking with minimal lateral movement of the pelvis. Of necessity, there must be some movement so the line of gravity will pass through the supporting foot. One proceeds, however, as if it were accomplished without lateral pelvic movement. Doing so requires more action in such muscles as the psoas major, the iliacus, the adductor brevis and longus, and the pectineus on the side of the pelvic prominence. One tends to tighten muscles on the back of the pelvis during the movement, so imagery should be used to thwart this (see p. 238). Repeated practice of this movement has resulted in eliminating both the sound and feeling of clicking. The movement is beneficial for anyone whose pelvis is laterally more prominent on one side, especially when the prominence is accompanied by greater indentation of the waistline on the same side. Always transfer the weight slowly to the limb on the side of the lateral pelvic prominence. Leg and Arm Movement Position. Four-legged (see p. 208). Before attempting work in the fourr legged position, study the design of the articulations of the arches of the vertebrae. In the four-legged position, weight must be transferred through

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

300

these articulations because the bodies of the vertebrae hang in a

more

or

and thus do not support weight. The weight of each vertebra from the atlas to the sacrum is transferred to the vertebra just beyond it and closer to the pelvis, thus supporting the logic of control of movement of the upper structures from the area of the pelvis, and in some instances, the control of the entire trunk and appendages from the proximal less parallel position

femora. The cat, for instance, through this type of control, can leap with

her young in her mouth and land on her front feet without biting her kitten.

To promote (1) better integration of the trunk during moveupper and lower extremities, and (2) more efficient muscle control of the upper structure at the pelvic base and the proximal femora. Purpose.

ment

of the

Procedure.

Be

certain that the wrists are directly under the shoulder

and that the hands are directed forward. Because this position of the hands stretches the multi-joint flexors of the wrist and fingers, some students prefer to close the fist and rest the weight on the back of the proximal

joints

avoid hyperextension of the elbows.

digits of the fingers. In either case,

The knees should be

and thus no farther head with that of the rib-case and the pelvis; and the upper directly

under the femoral

apart than the femoral sockets.

must be

in line

spine should be raised,

if

the back of the rib-case.

The

joints

central longitudinal axis of the

necessary, to place the shoulder blades closer to

A marked

indentation on the lateral sides of the

erector spinae muscles in the lumbar area indicates overly tight back

The student should experiment with voluntary movement to make the back as level as possible. Even though his front necessarily is higher bemuscles.

cause the arms are longer than the thighs, the student, in his imagination,

should think of the back as being level.

Slowly move an arm forward a short distance to remove support from one corner of the trunk without allowing the back, which is a table top, to change its position in space. Next, try to move the opposite thigh forward (or backward), a short distance to remove its support from the opposite comer of the table top, again without changing the position of the table. Finally, try moving the diagonally opposite arm and thigh slightly forward simultaneously, while maintaining the table top level and without lateral

movement. Imagery. To attain a better four-legged position, it sometimes helps imagine that a heavy weight is suddenly placed on the spine. The student thinks through the spinal column, trying to stabilize it (wdthout any movement) for this imaginary experience — an experience similar to that of to

the spine of a horse

when

The lower spine back; other spines

a rider jumps on

its

back.

of the "pelvis tucker" will often

may be concave

in the

same

be convex on the

area, like a sway-backed

VOLUNTARY MOVEMENT

301

been helped to find as level a position of his back as movement, the location and direction of movement to be imagined in various vertebrae of the spine to produce better alignment of the trunk will depend entirely on the appearance of his particular back. In the "pelvis tucker," the lumbar spine invariably will be curved slightly upward. Therefore, without any voluntary movement, the student may imagine the vertebrae, one after the other, beginning with the twelfth thoracic and progressing toward the pelvis, moving horse. After the student has is

possible through voluntary

downward

to rest at center-front of the knees. This process often

remolds

the lower back to approach the appearance of a level surface.

The image of during movement

the back as a table top helps to maintain

its

position

of an arm, a thigh, or both.

Comments. Very soon after assuming the four-legged position, the arms and wrists will become uncomfortable; they are supporting too much of the weight that should be supported by the thighs, mainly because the ribs are held upward toward the head by overly tight muscles. To rest the wrists and arms, the student may sit back on his heels, leaving the hands where they are.

be

If

maintaining the position of the hands

for a few,

hiss

mainly because of lack of

while slowly moving backward to

is

impossible (as

flexibility of the

sit

it

will

shoulder girdle),

on the heels (see

p. 278).

Then

return to the four-legged position and repeat the hissing several times while

moving the trunk backward toward the heels. Next, sit on the heels with the trunk upright and try hissing with the arms overhead (see p. 279)

may

be able to sit back on the heels from the four-legged position, leaving the hands where they were. Another way of resting the arms and hands is to assume the "fold-up" position with the arms resting on the floor along either side of the body several times. Following this procedure, the student

finally

(see p. 304). If

the knees hurt with the pressure of weight, place a foam rubber pad

under them — a pad the pelvis in

CRP.

like that

If

used

to

keep the

feet

from sliding away from

tension of the ankles causes discomfort in the ankles

and feet, place a small pillow under each ankle joint. Another movement which may be tried from the four-legged position is that of flexion at the femoral joints to move the trunk back only far enough to lift both hands from the floor so that the weight of the trunk is controlled entirely from the pelvis and proximal femora. Most students tend to tighten the outward rotators of the thighs more than necessary in this movement. This tightening can be reduced by any image which widens across the back of the pelvis (see p. 238). Still another movement, interesting because one can self-compete in its performance, is that of placing a small object in front of the knees at the

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

302

when the elbow is against the knees. Then, with the hands clasped lightly back of the trunk, move the trunk forward from sitting on the heels to pick up this object with the teeth— without falling on the face. This movement promotes sjmimetrical action of the back muscles as well as control of the trunk from the proximal thighs. distance reached by the finger tips

Forceful Stretching of Muscles Forceful stretching of muscles

is

practiced by athletes, gymnasts, and

dancers alike, in the hope of gaining greater freedom and range of move-

ment. The benefits .of the technique are difficult to assess, and its practice is not without danger. We do not, as yet, have sufficient information about the stretch reflex to know just how it responds to forceful stretching of the muscle. Mechanical properties of the muscle, length of muscle, and feed-

back from muscle spindles and Golgi tendon organs may

all

enter into the

picture.

Whether or not

movement, and most permanently, attained through improved skeletal alignment. Efficiency in skeletal alignment promotes balanced tone and suppleness of muscles around joints, and it allows the optimal range of movement inherent in the structure, limited only by design and ligamentous support of the joints and principles of muscle function. Improvement in such increase

skeletal alignment joints;

this

and

it

forceful stretching can increase the range of

best,

is

the primary requisite for increased flexibility of

is

should, therefore, be an integral part of forceful stretching

An

if

be practiced. example of a position suitable for muscle stretching, chosen from

questionable exercise

the dance,

may be

is

shown

is

to

in Figure 74. In this situation the stretching force

movement of the joint concerned, through movement which uses the weight of the body as a stretching force, or through the use of both. applied through voluntary

some common

and concomitantly greater safety, into the stretching procedure, the following should be known and understood: (1) the specific location of the muscles to be stretched; (2) the movement or lack of movement in a joint or joints which will stretch muscles either through voluntary movement, through an outside force, or both; (3) that the stretching of muscles must always be preceded by a good warm-up of the entire body; (4) that stretching should be slow, gentle, and steady; and (5) that stretching should always be stopped immediately In order to bring

if

sense,

pain occurs. In Figure 74

,

the muscles subjected to stretching are those on the back

which are already

in a

stretched position because of the straight knee and bent thigh joint.

The

of the left thigh joint, including the hamstrings

movement to be

used, either voluntarily or that brought about by an outside

VOLUNTARY MOVEMENT

A

Figure 74.

force,

is

dancer in position

303

for forceful stretching of muscles.

on the left thigh while maintaining a straight the right knee to lower the body weight and thus

flexion of the trunk

knee, and/or flexion of

bend in the left thigh joint. To encourage more efficient muscle coordination around the left femoral joint, visualize the left femoral joint as a hinge, and watch it closing slowly together. To produce better coordination of muscles of other areas subjected to pull by the position or by poor body alignment, imagine the left ischial tuberosity being elongated to the floor, and a grapefruit being moved down the left leg, as if it were a stocking, into the heel to bulge it into great size. Then envision lengthening the spine downward like a increase the

kangaroo

tail.

In the trunk, use imagined actions such as those advised for

the twelfth thoracic vertebra, the

and the central vertical be used to lower the ribs

first rib circle,

axis of the trunk (see p. 254). Hissing

may

also

toward the pelvic base. During all this mental activity, the force of stretching is applied slowly and gently, but with persistence. Forceful stretching of muscles at best is not a common sense approach for attaining greater flexibility. It survives because of the athlete's desire to "play the game" at whatever cost and th^ dancer's "do-or-die" attitude toward his profession. Nevertheless, the achievement of great skill in a chosen profession profits more from constructive thought applied during the learning process than from the unrestrained practice of inherently injurious techniques.

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

304

Tests of Skeletal Alignment

and

joint Flexibility

In ideal alignment of the skeletal framework,

all joints

provide a

full

range of movement^ as allowed by their design and ligamentous support. The following body positions are in accord with principles of muscle function and good mechanics. They are easily within the realm of achievement if one's alignment and movement have a high degree of efficiency. They

may be more

readily achieved, however, by the person of slender build.

The Fold-Up Position

The

fold-up position (see Figure 75)

is

not a rest position.

It is

one which

reveals the alignment and flexibility of the weight-supporting joints through-

out the body, and

To assume the line

it

should be used only as a test of these two attributes.

fold-up position, kneel on the floor with the knees in

with the thigh joints (not to the outside of them). The feet

straight, or the toes

may

turn inward, the latter being

more

may be

difficult for

most people. Sit back on the heels, or between them if the toes are turned inward. Then, maintaining contact of the pelvis with the heels, bend forward at the thigh joints to rest the trunk against the thighs and the forehead (not the top of the head) on the floor well in front of the knees. Let the shoulders sag forward as the arms rest on the floor on either side of the body.

This position requires the ability to bend sharply at the thigh and knee joints

while extending the ankle

joints.

The appearance

of the

back and

the position of the head will be governed by the degree of flexibility of the spinal column and the rib-case.

If

sufficiently flexible, the spine will

present a long, but slight, backward curve from the coccyx to the head,

and the forehead

on the floor. Overdeveloped muscles, and of the outward rotators on the back of the pelvis will limit bending at both the thigh and knee joints. If muscles in the low back are tight, the lumbar spine will not take part in the long backward curve but will be flattened in the area next to the pelvis. Differences in the height of the ribs on either side of the spine indicate lateral deviation in the spine and asymmetrical tone and bulk of the back muscles. Since no two persons have the same postural alignment, the appearance will rest easily

particularly of the thighs, legs,

Figure 75.

The

fold-up position.

VOLUNTARY MOVEMENT

305

is a strictly individual phenomenon. It gives the general idea, however, of the skeletal alignment of a person in teacher a the standing position and the flexibihty of the weight-supporting joints

of the fold-up position

any person in determining progress he works on his posture. To note the effects of high, inflexible ribs and shoulders on general flexibility, try the hissing technique with arms overhead (see p. 279) while sitting on the heels. Then follow the hissing by returning to the fold-up position to note whether it is easier. throughout the body.

It is

also useful to

toward better alignment and

Sitting with the Legs to

flexibility as

One

Side

on the floor with the legs to one side, for example, with the directed toward the left and the knees toward the right (see Figure Sit

The

feet 76).

right foot should contact the inside of the left thigh close to the knee,

with the

The

left

lower leg approximately at a 90-degree angle with the thigh.

femoral head will rotate inwardly while the right one rotates

left

outwardly. If

the thigh joints are fully flexible, both ischial tuberosities will rest

with even pressure on the floor, and both knees will likewise touch the floor, while the trunk remains upright without lateral bending in the spine. For most people this position will be easier to maintain with the legs on one side rather than the other. This tendency will be determined by the bilateral

asymmetry

and the Such muscles

of skeletal alignment in the standing position

pattern of greater muscle development which occurs with

it.

invariably will reduce the flexibility of the joints close to them.

lumbar spine, pelvis, and proximal agreement with the central pattern of asymmetry described on page 198, the position with the legs to the left will be easier If

one's pattern of alignment in the

femora

is

in full

Figure 76. Sitting with the legs to one side.

306

TO REDUCE STRAIN AND IMPROVE NEUROMUSCULAR COORDINATION

and the lumbar spine curves to the right. The reverse of this pattern would suggest greater ease with the legs to the right. It is not unusual, however, for a lateral curve in the lumbar

if

the

left pelvis is

prominent

laterally

spine, regardless of the pelvic deviation, to cause greater ease

when

legs are to the opposite side, to the convexity of the lateral curve.

the

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Index ^^^>/^^^>/>/>/>/v/^>s^

Note: Page numbers in

italics indicate illustrations.

Abduction, 14 Acetabulum, 32, 35, 58, 64 Acetylcholine, 160 Achilles tendon, 88, 91, 94 Acromion, 98-99 Adduction, 14 Agonist, see Muscle(s), agonist

Antagonist, see Muscle(s), antagonist

Ankle, see Joint, ankle

Aponeurosis, 121

Arm, 100-109

movement of, 107-109, 299-302 See also Hand; Joint, elbow; Wrist Articulation, see Joint

Vertebrae Vertebrae Axon, 158, 159, 166

Atlas, see

Axis, see

Backache, 5, 141, 199, 261, 273 Balance, mechanical, 18 relation to posture, 27-28, 174, 176-182, 186, 192 Blood vessels, affected by stretching, 140 Bone(s), 10 articulation of, see Joint

deformation of, 185-186 response to stress, 18-19, 60-61 See also Arm; Leg; Patella, etc. Bony levers, 22^0, 176, 184, 223 foot as, 28, 86 head as, 176 Bow legs, 82, 186 Brain, 153-i54 See also Cerebellum; Cerebral cortex Breast bone, see Sternum Breathing, see Centered breathing; Expiration; Hissing; Inspiration; Respiration Breathlessness, 137

Calcaneus, 85-86, 87 Capillaries, 134

Capitum, iOi -102, 105 Carrying (an object), 269-270 Cartilage, 11-12 deformation of. 185-186 fibrocartilage, 11-12, 35, 98 hyahne, 10, 11 semilunar, 75-76 Cauda equina, 43, 155 Center of gravity, see Gravity, center of Centered breathing, 280-281 Central nervous system, see Nervous system, central

Cerebellum, 154, 161 Cerebral cortex, 153-154, 161 Cerebrum, 153, 154 Circulatory system, 130, 132-135 Circumduction, 14 Clavicle, 97-98, 107, 181

Coccyx, 32, 36, 37 Condyles, 58, 59, 74, 75 femoral, 72-73, 76, 78, 81 occipital, 50, 176 tibial, 73-74

Conoid tubercle,

97, 100 Constructive rest position (CRP), see Position, constructive rest

Coronal plane,

9, 10,

14

Crus, 111

Curl-up

(exercise), 294,

Dance movement,

295 79 270-271

30, 41, 67, 70-71,

80, 82-83, 93-94, 116,

arabesque, 41, 70 grand battement en avant, 69-70, 182 plie, 67,

151,

151

Dendrites, 157-i58

313

INDEX

314

Diaphragm, 110-117 central tendon of, 112-113

Flexion (continued) of Uttle toes, 298

function in respiratory cycle, 113-115,

116-117 imagery for, 117, 277-278 structure of, 110-11 1, 112-113 Discs, intervertebral, 43, 45, 53 See also Spinal column; Vertebrae Dowager's hump, 178, 185

of spine, 55-56 of thigh(s), 65, 289-290,29i-292, 293295, 301 of wrist, 112, 151 Foot, 84-95

arches

of,

bony

87, 89, 90, 94

86 296-297 ligaments of, 88-90 line-of-movement for, 195-196, 243-244 movement of, 92-94, 295-299 imagery during, 272, 298, 299 mechanics of, 271, 272-273 See also Walking muscles of, 90-9i 92 problems, 94-95 rotation of, 298 structure of, 85, 86-87, 88-89, 90, 91-92 turn-out of, 65, 81, 82, 93, 272 Football punt, 29, 68-69 as

lever, 28,

flexion of,

Efficiency (of a machine), 25 Elasticity, 19

"Empty

suit" (image),

232-233, 234-237

Energy, 16-17 Epicondyle, 73, 101 Equilibrium, 18 in standing position, 145, 173

Everyday movement, mechanics

,

of,

261-

273 Exercises, curl-up, 294, 295

dangers of, 5, 294-295 value of, 138-139, 141 Exhaustion, see Fatigue Expiration, 113, 115, 11&-117, 130 imagery during, 117 See also Centered breathing; Hissing; Respiration Extension, 14

Foramen magnum,

50, 54

Force, 17

Force arm, 23-24, 25, 28, 29 Forearm, 103, 104 Forward head, 247-248, 287-289 Friction, 29

Exteroceptors, 161

Glenoid labrum, 35, 100 Gliding, 13, 24, 93 Glycogen, 127 Golgi tendon organ, 161,

139-140 Fasciculi, 122 Fatigue, 137-138

Fascia, 122,

Feedback

(biological),

role

in

movement,

166-167 Femoral joint, see Joint, femoral Femur, 58-71 bilateral ahgnment of, 198-200 change in alignment following posture

i 62-163,

164

Gravitation, 17

Gravity, 17

center

of,

178 176 pattern, 147

10, 18, 31,

line of, 10, 18, 79, 175, in

movement

Gymnastics, 5

education, 191

movement

of,

63-66

muscles surrounding, 63-64 response to stress, 60-61 structural design of, 58-63 view of, 59 Fibrocartilage, see Cartilage

Fibula, 73-74 relation to ankle joint,

87-88

Flexibility, 19 tests for,

304-306

Flexion, 14

of ankle joint, 88, 92-93, 148, 297 of elbow, 108, 147 of fingers, 108

Hallux valgus, 94 Hamstrings, see Muscle(s)

Hand, i05-106

movement

of,

107-108, 151

Handedness, relation to asymmetry of shoulder girdle, 200 Head, change in alignment following posture eduction, 191 eflFect

of position on respiration, 116

281-283 improve positon 249, 287-289 support of, 50, 54, 176-177 flexion of, 176,

imagery

to

of,

247-

of foot, 92, 296-297 of head, 281-283

of, 134-135, 136 Heel, see Calcaneus; Foot Hip joint, see Joint, femoral

of knee, 81

Hissing, 278-281

Heart, functioning

INDEX Horizontal plane, see Transverse plane Humerus, 100-iOi, 102, 103, 104

movement structure

7, 145-146, 148, 166, 169-170 on skeletal alignment, 187-192 in posture laborator>, 205. 222-231 See also Movement, imagined Iliofemoral ligament, see Ligament, Y Ilium, 32^33, 36 Imagerv, 'empt\ suit," 232-233, 234-237

Ideokinesis, effect

in constructive rest position,

232-236,

279, 280, 281, 284, 287-288, 289-

293, 297, 298

promote

lines of

300-301

movement. 237-

238, 239-240, 241-242, 243-244,

245-246, 247-248, 249 prone-King position, 281

251-253, 254, 279-280, 286, 288, 298 in standing position, 236, 254-255, 256, in sitting position, 236,

288, 296, 299 in

movement of protected by

structure

of,

72-76, 77, 78

lumbosacral, 33, 35, 36

of 13-14 304-306

mobility-

tests for.

movement

pubic symphysis. 33, 35, 37. 199 radioulnar, 105 sacroiliac, 33, 35, 199 scapulohumeral, see Joint, glenohumeral sternoclavicular. 97-98, 107. 181 thigh, see Joint, femoral Kicking, 68-69

with, 276--302

Knee(s). see Joint, knee

Knock-knees, 82, 186

Inertia, law of,

20 Inspiration, 113, ii5-117 See also Centered breathing; Respiration

Kyphosis, 54

Interarticular fibrocartilage, see Cartilage;

Lateral plane, see Sagittal plane

Meniscus

Labyrinthine receptors. 161-762. 163 Leg(s),

72-83

Interoceptors, 160-161

anterior and posterior view

Inversion, of the foot, 93

muscles

Joint(s),

acromioclavicular, 100. 102, 107 ankle, 84-95

movement

of,

80, 92-94,

295-297

94 structure of, 84-85 See also Foot of,

of,

74

78-80, 90-92

of,

22^0

laws of mechanics applied

elbow, 103-105 of,

to.

23-25

23-24, 28, 86. 90 third class. 23-24, 28-30, 90. 176 Lifting (a dancer), 270

second

class.

Ligament(s), 11

of ankle joint, 84, 87-88, 89 annular, 105 arcuate, external

12

movement

Lever(s), 16,

6rst class, 23-24, 27. 30, 43. 176, 180

centering weight at. 295-296 ligaments of, 87-88, 89 imager> \%ith, 243-244, 297

capsule

of,

preferential use of, 201, 273 See also Lower extremities

10-14

problems

stretch re-

144-145 muscles of, 78-80 problems of. 82-83 flex,

Kinesis, 7

walking position. 236. 25.5-257, 272

voluntar>

of, 61-62. 63 fulcrum for movement, 22. 25 glenohumeral. 102-103, 108 knee, 72-83 ligaments of, 73-77, 78 movement of, 24, 78-81

structure

as

neutral position. 13

in four-legged position,

in

location

of, 7 Oi

See also Arm Hyperextension, 14 Hvpertonicitv (of muscles), 184-185, 201 See also Muscles, development of

to

femoral (continued) of, 67 movement of, 40, 63-71, 79-^0, 301 muscles of, 63-66, 78-80

Joint(s)

107-108 -102

of,

315

and

internal. 111

62-63 of clavicle. 98

capsular. 108, 147. 151

femoral, 35, 58-71

change following posture education, 191, 195

305 imagery- for, 239-240, 241. 291. 303 ligaments of, 61-62, 63 flexibiUtv- of, 65,

cruciate, anterior

and

posterior. 73,

76, 77-78, 80, 81

deltoid.

88-89

of elbow joint. 105 of femoral joint. 36. 37. 61-62. 63 of foot, 88, 89-90

75-

INDEX

316

Movement

Ligament(s) (continued) of humerus, 102.

Y

iliofemoral, see Ligament,

inguinal,

36

of knee, 75-76, 77, 78, §1

ligamentum teres, 61-62 of pelvis, 36-37 Poupart's, see Ligament, inguinal

of shoulder-girdle, 98, 100, 102 of spinal column, 52-53, 54 stretching Y,

36^7, in

of,

140

66 backward bending, 262 38, 40,63,

in kicking, 68, 70,

182

of, 23 Line of gravity, see Gravity, line of Lines-of-movement, i93-196 from big toe to heel, 195-196, 243-244 from center of knee to center of thigh joint, 195, 239-240, 241 imagery with, 226-227, 237-23S, 239240, 241-242, 243-244, 245-246, 247-248, 249 to lengthen central axis of body upward, 196, 248-249 to lengthen spine downward, 193, 237-

Line-of-action, definition

to

to

238 narrow across front of pelvis, 195, 241-242, 243 narrow rib-case, 194, 241, 242

between mid-front of and 12th thoracic vertebrae, 193, 244-245, 246-247 from top of sternum to top of spine, 194 247-248 to widen across back of pelvis, 194, 238-239 Lower extremities, 58-95 frinction of, 181-182 movement of, 67-71, 81, 300 to shorten distance

of, 3, 5, 16, 25, 57 fundamental rule for everyday, 262-263 imagined, 6-7, 145-147, 148, 169-170, 222-231 ancillary responses to, 250-251 location and direction of, 192-196 positions for, 207-210, 215-221, 251257 in posture education, 187-188, 191192, 196, 210-212, 222-231 use with voluntary movement, 274302 versus voluntary effort, 222-223 kinds of, 13-14 limitation of, 13, 185-186 lines-of-, see Lines-of-movement location and direction of, 8-10, 25 mechanics for everyday, 261-273 patterns of, 4, 6, 25, 30, 68, 167-170

potential for, 3-4, 6, 7 role of nervous system in, 3-4, 153-170 speed and range of, 28-29, 148, 302-303 translatory, 24 voluntary, 4, 6, 7, 145-148, 157, 16^170, 274-306 principles for use of, 275-276 versus imagined movement, 222-223, 227 use with imagined movement, 274—302

See also Carrying; Dance movement; Flexion; Gliding; Kicking; Lilting;

pelvis

of, 201 See also Femur; Foot: Joint, ankle;

preferential use

Knee; Leg Lumbocostal arches, Lungs, 129-132

lateral

and medial. 111

Machine, definition of, 16 Mechanics, laws and principles of, 16-21 for everday movement, 261-273 importance in movement, 30 Menisci, medial and lateral, 75-76, 77, 78 Moment of force, 24 Motion, laws of, 20-21 Motoneuron, 158, 166 Movement, 3-7, 167-170 angular, 13 cortical control of,

(continued)

efficiency

146-147

Pulling; Pushing; Sitting; Squatting;

Stooping; Stair-climbing; Walking; as well as specific parts of the body, e.g. Foot,

movement

of

Movement

education, 3-7, 37, 128, 143 145-146, 166-170, 188, 227

See also Posture education Muscle(s), 121-152

abdominal, 116, 245, 289-294 action

of,

see Muscle(s), function of

adductor brevis and longus, 195, 239, 299 agonists, 15, 147, 250-251 antagonists, 15, 148, 250-251 "anti-gravity," 183

attachment

of,

26, 28, 121

biceps brachialis, 702-103, 105, 106, 151 cell,

see Muscle(s), fiber

contraction

of,

125-126, 127, 135-

136, 139, 148, 164

See also Stretch reflex of, 142-143, 201 See also Hypertonicity; Muscle(s), hypertonic

development

erector spinae, 300

INDEX Muscle(s) (continued)

Muscles (continued)

extensor, see Muscles, "anti-gravity"

rectus femoris, 79, 151

121-122, 123^124, 125-126 contraction and stretching of, 125-

in respiration, 110,

127, 139, 163-164

serratus anterior, 283

fiber,

of diaphragm, 110-iii, 112

164 intrafusal, 123-124, 164 fibrils, 123-124, 126 actin, 123, 124, 126 myosin, 123, 124, 126 fiinction of, 129-143 action on bony levers, 26-29 control of, 145-148 principles of, 144-152 relation to resting length, 148-149 role in posture, 183-185 synergistic action of, 149-150 timing of, 147 gastrocnemius, 80, 92, 93, 150-151 gluteus maximus, 149 gracilis, 80 extrafusal, 123-724,

hamstrings, 63, 65, 70, 79-80 arising

from squatting position, 151,

268

297

in foot flexion,

imagery

240 and extension, 151-

to release tightness,

in thigh flexion

152, 290, 291 hypertonic, 184-185, 201-202, 217-

218 See also Hypertonicity; Muscles, development of iliacus, 59, 195,

317

299

116

sartorius, 80, 149

smooth, 123 soleus, 92 soreness

141, 212

of,

spindle, 123, 136, 162-164, 165

See also Muscle, fiber 15 sternocleidomastoideus, 116, 282

stabilizers,

stretching

13^141, 302-303

of,

302-^03 imagery during, 303

in dance,

See also Stretch reflex 123

striated,

121-124 19 synergists, 15, 149-150 structure

of,

suppleness

in,

tension recorders,

i 62-163

149 tibialis anticus, 298 tone of, 135-136 training of, 145 trans versalis, lll-ii2, 116, 242 trapezius, 106 triceps, 103, 106, 150, 151 two-joint, 63-64, 78-80, 150-152 See also specific parts of the body, Leg, muscles of, etc. Muscle boundness, 135 tensor fascia

lata,

e.g.

Myofibrils, see Muscle(s), fibrils

Myoglobin, 133

ihopsoas, 40, 59, 239, 242 latissimus dorsi, 38, 106

Navicular, 86-87, 89, 93

longus capitus, 283

Nerve Nerve

in

movement, 3-^, 14-15,

22, 26-29,

144-152, 169-170

251

150-151

obturators internus and externus, 38 one-joint, 78-79, 150-151

oxygen demand by, 129, 136 pectineus, 195, 239, 299 pectoralis major and minior, 283 peroneus longus, 91, 145 plantaris, 80 popliteus, 73, 75, 78, 80 299 quadratus lumborum. 111, 116 quadriceps extensor, 79, 80 rectus capitis anterior, 283

283

and

Neuron

of,

160

140

Nerve impulse transmission, 158-i59, 160 Nerves, cranial, 156 spinal, 43, 155, 156 Nervous system, 3^, 15, 22, 153-170 autonomic, i 56-157

153-155 and imagined movement, 224, 227, 251 role in movement, 125, 127, 145, 146, 147, 153-170 peripheral, 155-156 voluntary (cerebrospinal), 156-157 Neuron, 155, 157-i58, 15&-160 motor neuron, 158 Newton's laws of motion, 20-21 central, 6, 26,

psoas major, 38-