Sports engineering is an interdisciplinary subject, which encompasses and integrates not only sports science and enginee
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English Pages 535 [519] Year 2000
Table of contents :
The Engineering of Sport
CONTENTS
PREFACE
1— SPORTS ENGINEERING
Sports Engineering: History, Philosophy and Policy
Introduction
Causes and Effects of Technological Change
The Socio-Economic Context
Sports Engineering Revisited
References
The Development of Sports Engineering around the World
Introduction
Sports Engineering and the Athlete
The Effect of Engineering on Sports
Sports Engineering and Business
Sports Engineering Research around the World
Conclusions
Acknowledgement
References
2— DESIGN AND SPORTS TECHNOLOGY
Technology Coupling in the Design of Sports Equipment
Innovation and Information
Methods of Creativity
The Product Design Profile
The Material of Sport: The Sport of Material
A Methodology for Technology Coupling
CES-Sports Relational Data Structure
CES-Sports: The Product Table
CES-Sports: Mechanical Links
Use of the Database for Selection and Inspiration
Fishing Rods with Golf Clubs
Snowshoes with Tennis Racquets
Conclusions
References
Design of Sports Equipment as a New Academic Field – Challenges and Experiences
Design of Sports Equipment - A Surprisingly Void Intersection of Opportunities and Needs
Demand Explosion: About Sports, Trends, and Demographics
Student's View: About Fun, Interdisciplinary Experiences, and Job Opportunities
Academic Foundations: About Design Engineering Applied
Design of Sports Equipment - Exploring the Void
Design of Sports Equipment - Approaches to Filling the Void
Seminar and Project Seminar: "Design of Sports Equipment"
The "Interdisciplinary Sports Equipment Job-Shop"
Projects and Research
Organizational Approaches
Design of Sports Equipment - Conclusions to Get Started
References
Design of Real Tennis Balls
Introduction
Design Considerations for Real Tennis Balls
Coefficient of Restitution
Compression Testing
Other Design Considerations
Alternative Materials and Manufacturing Processes
Conclusions
Acknowledgments
References
Advanced Materials in Golf Clubs
A Game Called Golf
Design of Golf Equipment
Drivers and Fairway Woods
Irons
Putters
The Future
Concluding Remarks
References
Acknowledgement
Innovative Golf Clubs Designed for the Amateur
Introduction and History of the Development
Force Patterns
Club Design Principals
Other Considerations
Initial Testing
Patents
Summary
References
Development of the Aqua Golf Club
Introduction
Method
Mathematical Model
Procedure of Analysis
Result
Parameter Values
Estimation of Torques
Centre of Gravity Movement in the Aqua Golf Club
Simulation of Aqua Golf Club
Conclusion
References
Three-Dimensional Shape of the Golf Club during the Swing
Background to the Work
Role of the Shaft in the Golf Swing
Role of the Shaft at Impact with the Ball
Procedures for Shaft Testing
Results of Shaft Testing
Summary and Conclusions
References
Surface Hardness of Cricket Bats Following 'Knocking-In'
Introduction
Experimental Apparatus
Bat Knock-In Device Design
Modifications to Knock in Device
Surface Hardness Penetrator
Ball Mallet
Scanning Electron Microscope
Experimental Method
Penetration Tests
Electron Microscope Examination
Results and Discussion
Hardness Tests
Conclusions
References
The Thermal Comfort of Bicycle Helmets
Introduction
Methods
Results
Sample Size
The Thermal Comfort of Bicycle Helmets
Hot Spots on a Helmeted Head
Improvements to Bicycle Helmets' Ventilation Design
Airflow over the Helmeted Head
Additional Information from Cyclists
Discussion
Recommendations & Further Work
Conclusions
Acknowledgments
References
The Design of a Traction-Measuring Device for Footwear
Introduction
Materials and Methods
The RMIT Traction Device
Performance Requirements
Description of the Device
Vertical Displacement
Force Plate and Calibration
Reliability of the Device Based on Repeated Tests
Surfaces
Natural Surfaces
Artificial and Timber Surfaces
Footwear
Commercial Footwear
Modelled Footwear
Results and Discussion
Conclusion
References
Development of Artificial Muscular Actuator Simulated Human Muscular Characteristics
Introduction
Experiment
Results
Design of Artificial Muscular Actuator Simulated Human Muscular Characteristics
Dynamic Simulation in AMA Model Driving
Development of AMA Simulated Human Muscular Characteristics
References
Performance of Newly Developed Automatic Belay Device for Mountain Climbers
Introduction
Measurement of Rope Tension as a Function of Time
Optimization of MSA Using 'Energy Equation'
Conclusions
Acknowledgement
References
Direct Measurement of Propulsive Forces in Swimming Using a Mechanical Arm
Introduction
Methods
Arm Model Design
Anthropometric Construction
Mechanical Construction
Movement and Control
Experimental Design
Data Processing
Results
Position and Angular Velocity Measurements
Force Measurement Results
Discussion
Conclusion
References
Design of an Equestrian Stirrup with a Bi-Directional Release Mechanism
Introduction
Design Critique
Kinematic Model of the Release Mechanism
Design Considerations
Conclusion
Acknowledgments
References
3— ENABLING KNOWLEDGE
Cricket Ball Aerodynamics: Myth versus Science
Introduction
Aerodynamics of Conventional Swing
Aerodynamics of Reverse Swing
Swing on the Cricket Ground and Ball Tampering
Swinging an Old Ball
Effects of Meteorological Conditions
Myths and Misconceptions
Conclusions
References
The Drag Coefficient of Tennis Balls
Introduction
Methods of Obtaining High Re
Apparatus
Wind Tunnel
3 Component Wind Tunnel Balance Set-Up
Method
Determining Drag Forces
Results
Obtaining C[sub(D)]
Discussion
C[sub(D)] of a Tennis Ball
Constant C[sub(D)] for All Re
Use of Shrouds
Accuracy of Results
Conclusions
References
Acknowledgement
Predicting the Dynamic Behaviour of Cricket Balls after Impact with a Deformable Pitch
Introduction
Classical Theory
Modified Theory
Results and Discussion
Conclusions
Acknowledgements
References
Modelling of an Oblique Tennis Ball Impact on a Court Surface
Introduction
Data Collection
Theoretical Model
Moving the Centre of Mass of the Ball
Results
Discussion
Conclusions
Acknowledgements
References
On Measuring the Performance of Wood Baseball Bats
Introduction
Methods
Players, Bats, and Balls
Data Collection
Data Analysis
Results
Discussion
Acknowledgements
References
Determining Baseball Bat Performance Using a Conservation Equations Model with Field Test Validation...
Introduction
The Energy Exchange
Nomenclature
Integrating Theory and Lab Tests
Laboratory Tests
Performance Predictions
Field Tests
Results
Conclusions
References
Physical Properties of Tennis Strings
Introduction
Experimental Methods
Elongation Results
Tension Loss Results
Impact Results
Results with a Steel Ball
References
Comparison of Standard and Oversize Tennis Balls for Normal Impacts on a Racket
Introduction
Experimental Procedure
Experiment 1
Experiment 2
Results
Experiment 1
Experiment 2
Experiments 1 and 2
Discussion
Conclusions
Acknowledgement
References
Analysis of Large Deformation of Japanese Bows
Introduction
Theoretical Analysis
Theoretical Predictions and Experimental Results
Conclusions
Acknowledgments
References
Simulation of Ski Bending Deformation While Turning: Initial Modeling of the Carving Turn
Introduction
Cutting Resistance Forces
Bending Deformation during Turning
Equations of Motion
Numerical Examples
Conclusions
References
The Determination of Rowing Rigger Dynamic Performance-Deflection Criterion
The Evolution of Rowing as a Sport
Rigger Development
Rigger Performance – Deflection Criteria
Laboratory Based Trials
On-the-Water Rigger Deflection Measurement
Discussion of Results
Conclusions
References
Effects of Front Suspension on Mountain Bike Impact Performance
Introduction
Procedures
Suspension Conditions
Single Subject
Experimental Conditions
Testing Procedures
Data Analysis
Results
Forces
Impulse
Discussion
Conclusion
References
Performance Optimization of High Speed Ski Runner
Introduction
Wind-Tunnel Simulation and Measurement Methods
Results and Discussion
Conclusion
Acknowledgement
References
Evaluation Method for the Energy Expenditure in a Daily Outdoor Cycling Exercise
Introduction
Energy Expenditure
Measuring System
Experiment
Results
Method for Evaluation
Conclusion
References
Kinematics of Upper Limb Movement in Different Level Tennis Athletes Using Forehand Drive
Introduction
Materials and Methods
Results and Discussion
Conclusions
Acknowledgement
References
Differences of Tennis-Swing Style between Experts and Beginners and Its Dynamical Influences on Play...
Introduction
Experiment
Experimental Results
Measured Results of Swings
Measured Results of Angles of Arms and Racket
Influences to the Arm and Guidance for Tennis
Conclusions
References
Release of the Force Balance in Highly Skilled Archers: Connections of the Bow's Motion with EMG Dat...
Introduction
Methods
EMG
Moments of the Click, Release and Contact-Loss
Laser, Video, Accelerometer and EMG
Test-Design
Subjects
Second Part: EMG, Video, Laser, Accelerometer
Concluding Remarks
References
The Frequency Response of Acupuncture Meridians
Introduction
The Acupuncture Meridian System
Electrical Properties of Acupuncture Points
Method
Results & Discussion
Conclusions
References
Pulsed Electromagnetic Field Therapy for Exercise-Induced Muscle Injury
Introduction
Methods
Study Design and Power Calculation
Subjects and Induction
Intervention
Outcome Measures
Subjective Pain Measures
Muscle Tenderness (As Measured by Mechanical Pain Threshold)
Range of Motion (Ankle Stiffness)
Lower Limb Volume
Serum Creatinine Kinase
Statistical Analysis
Results
Exclusions
Maximum Pain Score
Mechanical Pain Threshold
Range of Motion
Ankle Stiffness
Leg Volume
Serum Creatinine Kinase
Discussion
References
A Contact Pressure Based Prosthetic Fitting Device for a Total Knee Arthroplasty (TKA)
Background
Methods and Materials
Measurement and Data Collection
Experimental Procedure
3-D FEM Model of the Tibial Component
Data and Results
Discussion and Conclusion
References
Transformative Aspects of Sport – A Philosophical Approach to Sports Medicine
Transformative States in Sport
Physiology, Psychology and Sport
Subjects
Experimental Design
Equipment
Method
Results
Case Study
Discussion
Limitations
Future Directions
Conclusion
References
4— ADVANCED ANALYSIS TECHNIQUES
An Investigation of Flowfield Influences around the Front Wheel of a Formula 1 Car
Introduction
CFD Analysis and Facilities
Experimental Facilities
Geometry Configurations
CFD Configurations
Experimental Configurations
CFD Results
Experimental Results
Discussion
CFD Results
Endplate variations
Barge board variations
Experimental Results
Concluding Remarks
References
3D Computational Fluid Dynamics in Competitive Sail, Yacht and Windsurf Design
Introduction
CFD Methodology
Grid Generation
Flow Solution
Free Surface
Wind Shear
Industry Examples
America's Cup Yacht
Windsurfing
Windsurf Fin
Planned Enhancements
Conclusions
Acknowledgments
References
Computational Fluid Dynamics of a Shuttlecock
Introduction
Flow Visualisation
Geometry Construction
CFD Solution
Concluding Remarks
References
Characterizing the Performance of Baseball Bats Using Experimental and Finite Element Methods
Introduction
Bats and Engineering Design
Physical Differences between Wood and Aluminum Bats
Measuring and Limiting Batted Ball Speed
Modeling the Baseball
Modeling the Baseball Bat
Modeling the Bat/Ball Impact
Results
Conclusions
Acknowledgements
References
Simulation of Energy Absorption Effects during Collision between Helmet and Hard Obstacles
Introduction
Basic Statements and Interrelations
Nonlinear Behavior Analysis
Material Nonlinearity Aspect
Geometric Nonlinearity Aspect
Contact Nonlinearity Aspect
Research Methodology
Adaptive Finite Element Procedure Selection
Analytical Model
Displacement Control Method
Arc-Length Method
Helmet Modeling and Discretisation
Conclusion
References
Dynamic Responses of Helmets for Sports in Falling Impact Onto Playing Surfaces
Introduction
Construction of Finite Element Models
Free Drop Impact Tests
Drop Impact Simulations
Conditions of Simulations
Results and Discussions
Parametric Studies
Conclusions
References
Dynamic Finite Element Simulation of Fly Casting and Its Potential Use in Fly Rod Design
Introduction
Methods
Results
Summary and Conclusions
References
Analysis of the Elastic-Plastic Strain Developed around a Square Taper Fixing. "The Strengths and We...
Introduction
Preliminary Observations
Crank Failures
Elastic-Plastic Analysis
1— Elastic Analysis
2— Elastoplastic Analysis
Conclusions
Acknowledgements
References
Infrared Thermography of the Tensile Behavior of Natural Gut String
Introduction
Method
Results
Natural Gut String
Synthetic String
Dry Sliding of Natural Gut String at Nodes
Conclusion
References
3D Modeling of Wind Conditions for a Full-Size Tennis Court
Introduction
Apparatus and Experimental Procedure
Wind Tunnel Model
Computer Model
Interpretation of Results
Concluding Comments
References
Loads Distribution Along a Sail-Mast
Introduction
Method
Mast Structural Behavior
FINN Class Sail-Mast System
Structural Analysis of the Mast
Sail Loads Calculation Method
Results
Conclusions
References
Accuracy of Wind Measurements in Athletics
Introduction
The Effect of Wind on 100m Sprint Times
Is the Current Wind Measurement Method Appropriate?
Methods
Results
Discussion
Conclusion
Acknowledgements
References
Specification Estimation and Analysis of Driver Swing by the Difference in Golf Club Specification
Introduction
System and Problem Description
Method
Driver Swing Variables
Multiple Regression Analysis
Neural Network
Variable Sensitivity for Arm Rotational Motion
Measurement System
Estimation of Driver Swing
Golf Club Specification and Swing
Estimation by Multiple Regression Analysis
Estimation of Driver Swing by the Artificial Neural Network
Golf Club Specifications That Influence Swing Motion
Conclusion
References
The Adaptation of Golf Swing to Inertia Property of Golf Club
Introduction
Methods
Modeling of Golf Swing
Cost Function
Optimal Control Program
Computation of the Optimal Controls
Sensitivity Analysis
Results and Discussions
Optimizing Criteria of Golf Swing
Effect of Inertia Property of Club to Golf Swing
Effect of Total Club Mass to Golf Swing
Effect of Head/Shaft Mass Ratio to Golf Swing
Effect of Club Length to Golf Swing
Effect of Club Head Velocity to Golf Swing
References
The Effect of Glove Band in the Golf Swing
Introduction
Problem Description
Glove Band
Problem Description
Method
Electromyogram (EMG)
Club Head Speed
Wrist Angular Motion
Experiments
Experimental System
Experimental Conditions
Examinee
Experimental Conditions
Experimental Results
Electromyogram(EMG)
Wrist Angular Motion
Club Head Speed
Conclusion
References
Comparison of Curve Ball Kick with Instep Kick in Football
Introduction
Methods
Experiment
Computer Simulation
Results and Discussion
Basic Kinematics
Validity of Simulation Model
Impact Force during Ball Kick
Release Angle at Impact
References
A Review of Techniques Used to Evaluate Load Carriage
Introduction
Aim
Summary of Techniques Used to Evaluate Load Carriage
(1)— Subjective Perceptual Methods and Ratings of Perceived Exertion
(2)— Mechanical
(3)— Anthropometrical
(4)— Medical
Improving Load Carriage Evaluation
Conclusion
Acknowledgements
References
Analysis of Stroke Technique Using Acceleration Sensor IC in Freestyle Swimming
Introduction
Method
Acceleration Sensor IC
Underwater Cinematography
Results
Wrist Acceleration
Three Dimensional Video Analysis
Discussion
Maglischo's Stroke Pattern Definition
Relationships between Acceleration and Hand Movement
X-Axis Acceleration
Y-Axis Acceleration
Z-Axis Acceleration
Conclusion
References
Lateral Vibration Characteristics of Road Racer Bicycles
Introduction
The Bicycles in the Experiment
The Natural Frequencies and Modes
Frequency Response for the Random Excitation
Conclusion
References
Environmentally-Conscious Materials Selection and Design of Sports Equipment
Introduction
The Selection Methodology
Multi-Objective Optimisation in Materials Selection
Value Functions
Case Study: The Surfboard
The Manufacture of Surfboards
Environmental Impacts of the Surfboard
The Design Requirements and Performance Metrics
The Surfboard Core
The Surfboard Face
Value Functions for the Core and the Face
The Core
The Face
The Selection: Materials for Surfboards
Postscript
Conclusions
References
AUTHOR INDEX
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
S
T
U
V
W
Y
SUBJECT INDEX
A
B
C
F
G
H
M
R
S
T
Page i
The Engineering of Sport Research, Development and Innovation Edited by A.J. Subic Department of Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Australia S.J. Haake Department of Mechanical Engineering, The University of Sheffield, Sheffield, UK
Page ii
Copyright © 2000 by Blackwell Science Ltd Editorial Offices: Osney Mead, Oxford OX2 0EL 25 John Street, London WC1N 2BL 23 Ainslie Place, Edinburgh EH3 6AJ 350 Main Street, Malden MA 02148 5018, USA 54 University Street, Carlton Victoria 3053, Australia 10, rue Casimir Delavigne 75006 Paris, France Other Editorial Offices: Blackwell WissenschaftsVerlag GmbH Kurfürstendamm 57 10707 Berlin, Germany Blackwell Science KK MG Kodenmacho Building 7–10 Kodenmacho Nihombashi Chuoku, Tokyo 104, Japan The right of the Author to be identified as the Author of this Work has been asserted in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. First published 2000 Set in 10/12pt Times Printed and bound in Great Britain by MPG Books Ltd, Bodmin, Cornwall The Blackwell Science logo is a trade mark of Blackwell Science Ltd, registered at the United Kingdom Trade Marks Registry DISTRIBUTORS Marston Book Services Ltd PO Box 269 Abingdon Oxon OX14 4YN (Orders: Tel: 01235 465500 Fax: 01235 465555) USA Blackwell Science, Inc. Commerce Place 350 Main Street Malden, MA 02148 5018 (Orders: Tel: 800 759 6102 781 388 8250 Fax: 781 388 8255) Canada Login Brothers Book Company 324 Saulteaux Crescent Winnipeg, Manitoba R3J 3T2 (Orders: Tel: 204 8372987 Fax: 204 8373116) Australia Blackwell Science Pty Ltd 54 University Street Carlton, Victoria 3053 (Orders: Tel: 03 9347 0300 Fax: 03 9347 5001) A catalogue record for this title is available from the British Library ISBN 0632055634 Library of Congress Catalogingin Publication Data is available For further information on Blackwell Science, visit our website: www.blackwellscience.com
Page iii
CONTENTS Preface
viii
1 Sports Engineering
1
Sports Engineering: History, Philosophy and Policy A.J. Subic
3
The Development of Sports Engineering around the World S.J. Haake
11
2 Design and Sports Technology
19
Technology Coupling in the Design of Sports Equipment K.W. Johnson, H.R. Shercliff, M.F. Ashby
21
Design of Sports Equipment as a New Academic Field – Challenges and Experiences E.F. Moritz
35
Design of Real Tennis Balls K.M. Knowles, A.J. Cooke, T. Lennox, S. Mastropietro
43
Advanced Materials in Golf Clubs C. Shira, F.H. (Sam) Froes
51
Innovative Golf Clubs Designed for the Amateur J.S.B. Mather
61
Development of the Aqua Golf Club S. Nishizawa, T. Sugiyama, K. Watanabe
69
ThreeDimensional Shape of the Golf Club During the Swing J.S.B. Mather, S. Jowett
77
Surface Hardness of Cricket Bats Following 'KnockingIn' A.T. Sayers, M. Koumbarakis, S. Sobey
87
The Thermal Comfort of Bicycle Helmets A. Ellis, A. Bertolini, L. Thompson
95
Page iv
The Design of a TractionMeasuring Device for Footwear E.B. Barry, R. Kummer, P.D. Milburn
103
Development of Artificial Muscular Actuator Simulated Human Muscular Characteristics A. Shionoya, Y. Sakurai, M. Yachida, M. Hasegawa, H. Miyake
113
Performance of Newly Developed Automatic Belay Device for Mountain Climbers S. Ishioka, F. Nakajima, K. Nakagawa
123
Direct Measurement of Propulsive Forces in Swimming Using a Mechanical Arm M.A. Lauder, P. Dabnichki, R.M. Bartlett, T. Mckee
131
Design of an Equestrian Stirrup with a BiDirectional Release Mechanism J. Schneller and A. Subic
139
3 Enabling Knowledge
151
Cricket Ball Aerodynamics: Myth versus Science Rabindra D. Mehta
153
The Drag Coefficient of Tennis Balls S.G. Chadwick, S.J. Haake
169
Predicting the Dynamic Behaviour of Cricket Balls after Impact with a Deformable Pitch M.J. Carré, S.J. Haake, S.W. Baker, A.J. Newell
177
Modelling of an Oblique Tennis Ball Impact on a Court Surface R.J. Dignall, S.J. Haake, S.G. Chadwick
185
On Measuring the Performance of Wood Baseball Bats J.J. Crisco, R.M. Greenwald, L.H. Penna, K.R. Saul
193
Determining Baseball Bat Performance Using a Conservation Equations Model with Field Test Validation L.P. Fallon, R.D. Collier, J.A. Sherwood, T. Mustone
201
Physical Properties of Tennis Strings R. Cross
213
Page v
Comparison of Standard and Oversize Tennis Balls for Normal Impacts on a Racket S.R. Goodwill, S.J. Haake
221
Analysis of Large Deformation of Japanese Bows A. Ohtsuki, S. Ohshima
229
Simulation of Ski Bending Deformation While Turning: Initial Modeling of the Carving Turn Y. Hirano, N. Tada
239
The Determination of Rowing Rigger Dynamic PerformanceDeflection Criterion D. Aitchison
247
Effects of Front Suspension on Mountain Bike Impact Performance M. Levy, G.A. Smith
255
Performance Optimization of High Speed Ski Runner D. Favier, C. Maresca, E. Berton, A. Agnès, F. Pous
265
Evaluation Method for the Energy Expenditure in a Daily Outdoor Cycling Exercise H. Kagawa
273
Kinematics of Upper Limb Movement in Different Level Tennis Athletes Using Forehand Drive L.H. Wang, F.C. Su, H.W. Wu, K.C. Lo
281
Differences of TennisSwing Style between Experts and Beginners and Its Dynamical Influences on Players H. Takada, S. Takahashi
289
Release of the Force Balance in Highly Skilled Archers: Connections of the Bow's Motion with Emg Data J. EdelmannNusser, M. Gruber
299
The Frequency Response of Acupuncture Meridians H. Lazoura, I. Cosic
309
Pulsed Electromagnetic Field Therapy for ExerciseInduced Muscle Injury M. Cohen, B. Heath, B. Lithgow, I. Cosic, M. Bailey
317
Page vi
A Contact Pressure Based Prosthetic Fitting Device for a Total Knee Arthroplasty (TKA) F. Amirouche, L. Aram, M. Gonzalez, R Giachetti, C. Mahr
329
Transformative Aspects of Sport – A Philosophical Approach to Sports Medicine J. Charalambous, A. Charalambous, I. Cosic
339
4 Advanced Analysis Techniques
351
An Investigation of Flowfield Influences around the Front Wheel of a Formula 1 Car W.P. Kellar, G.J. Targett, A.M. Savill, W.N. Dawes
353
3D Computational Fluid Dynamics in Competitive Sail, Yacht and Windsurf Design J.M. Pallis, D.W. Banks, K. Okamoto
361
Computational Fluid Dynamics of a Shuttlecock M.H. Frank, A.J. Cooke, R.S. Cant
371
Characterizing the Performance of Baseball Bats Using Experimental and Finite Element Methods J.A. Sherwood, T.J. Mustone, L.P. Fallon
377
Simulation of Energy Absorption Effects During Collision between Helmet and Hard Obstacles C. Mitrovic, A. Subic
389
Dynamic Responses of Helmets for Sports in Falling Impact Onto Playing Surfaces C.W. Ko, S. Ujihashi, N. Inou, K. Takakuda, K. Ono, H. Mitsuishi, D. Nash
399
Dynamic Finite Element Simulation of Fly Casting and Its Potential Use in Fly Rod Design M.A. Hendry, M. Hubbard
407
Analysis of the ElasticPlastic Strain Developed around a Square Taper Fixing. "The Strengths and Weaknesses of the Bicycle Crank." J. Morgan, N. Woodman
415
Infrared Thermography of the Tensile Behavior of Natural Gut String M.P. Luong
423
Page vii
3D Modeling of Wind Conditions for a FullSize Tennis Court Z. B. Gradinscak
431
Loads Distribution Along a SailMast S.M. Malpede, M. Vezza, D.P. Coiro
441
Accuracy of Wind Measurement in Athletics N.P. Linthorne
451
Specification Estimation and Analysis of Driver Swing by the Difference in Golf Club Specification S. Nishizawa, T.Sugiyama, M. Hokari, K. Watanabe
459
The Adaptation of Golf Swing to Inertia Property of Golf Club Y. Kaneko, F. Sato
469
The Effect of Glove Band in the Golf Swing M. Saito, K. Watanabe, S. Nishizawa, T. Sugiyama
477
Comparison of Curve Ball Kick with Instep Kick in Football T. Asai, O. Murakami, M. Nasako
487
A Review of Techniques Used to Evaluate Load Carriage J.T. Anderson, L.A. Thompson
495
Analysis of Stroke Technique Using Acceleration Sensor IC in Freestyle Swimming Y. Ohgi, M. Yasumura, H. Ichikawa, C. Miyaji
503
Lateral Vibration Characteristics of Road Racer Bicycles T. Saito, H. Tago, Y. Chiba
513
EnvironmentallyConscious Materials Selection and Design of Sports Equipment U.G.K. Wegst, M.F. Ashby
521
Author Index
533
Subject Index
535
Page viii
PREFACE Sport as we know it today is closely integrated with technology. Athletes are participating in increasingly complex technological systems that require more understanding than they did in the past. The quest for new markets, records and sports supremacy has lead to millions of dollars being spent in research and development of sport technique and equipment, especially over the last 20 years. While new technologies have made sport faster, more powerful and enjoyable in many ways, they have perhaps unintentionally changed the type and pattern of injury experienced by athletes. Sports engineering research has focused over the years on understanding the consequences of increasingly complex sport technologies, and on developing new technologies that can improve not only performance and enjoyment but also safety. Like almost any engineering solution, the design of new equipment for sports represents a compromise, whereby decisions about new technology go hand in hand with the underpinning sport technique and governing rules. Decisions about sports technology are also political and social rather than just scientific or technical. Sports engineering is an interdisciplinary subject, which encompasses and integrates not only sports science and engineering but also much broader issues that are of paramount importance to developing and implementing new sports technology. The Engineering of Sport: Research, Development and Innovation aims to provide an overview of the stateoftheart in sports technology and the latest contemporary developments in this area from the perspective of both industrial practice and academic research. It encompasses the work carried out by researchers from Europe, North America, Asia, Australasia and Africa. The selected contributions have been refereed and were presented at the 3rd International Conference on the Engineering of Sport held in Sydney in June 2000 prior to the Sydney 2000 Olympic Games. The book has been edited and its contents divided into four interrelated sections: Sports Engineering, Design and Sports Technology, Enabling Knowledge and Advanced Analysis Techniques. All sports and leisure interests were considered and the selection of contributions was made based on their scholarly values and research merit. The Engineering of Sport conference series was initiated in 1996 with the first conference held in Sheffield (UK). From the very beginning, this international conference aimed at establishing and enhancing communication and cooperation between leading world researchers from industry and academia working on sport and leisure related engineering projects. The conference series offered a platform for the international society of researchers in science and practice for presentation and discussion of issues, problems, solutions and methods in the multidisciplinary area of sports engineering including design, materials, instrumentation, biomechanics and bioelectrics, aerodynamics, mechanics, motion and vibration analysis, advanced computational modelling and simulation, and perceived trends for the future. Sydney 2000 is the third conference in the series. It follows the formal launch of the International Sports Engineering Association (ISEA) in 1998 and the new international journal Sports Engineering published by Blackwell Science. The Conference was hosted by RMIT University in cooperation with the International Sports Engineering Association (ISEA). We gratefully acknowledge our colleagues and practising engineers who have made this publication possible with their research work and written contributions. A book on the interdisciplinary subject of sports engineering, as diverse in topics and approaches as this one, should be of interest to sports technology researchers and enthusiasts whatever their scientific background or persuasion. We must thank our publisher for continuous support of sports engineering and assistance in this production. ALEKSANDAR SUBIC AND STEVE HAAKE EDITORS, JUNE 2000
Page 1
1— SPORTS ENGINEERING
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Sports Engineering: History, Philosophy and Policy A.J. Subic Department of Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Australia ABSTRACT: The emerging discipline of sports engineering is not easily defined. One distinctive feature of sports engineering that draws together both sport science and engineering is technology. As consequences of technological change in sports are far reaching the decisions about sports technology cannot be based only on scientific and technical considerations. This paper explores broader issues that complement science and technology in sports including history, philosophy and policy. A deeper understanding of these underpinning issues is required as a prerequisite for the development of sports technologies capable of meeting the needs of athletes and the society in general.
Introduction Sports historian Allen Guttman first observed in his book From Ritual to Record, that ancient Greek athletics, including Olympic games themselves, lacked a concept basic to our enjoyment: the idea of a measurable level of performance that, once achieved, sets a benchmark for future athletes to surpass (Guttman, 1978). The prestige of ancient Greek and Roman athletes was based on stories of their prowess, not on records. They were proud of their victories and not of performance statistics as we know them, not just because they lacked chronometers or other highperformance equipment but because the concept of record was foreign to them. (Tenner, 1997). Since the revival of the games by Pierre de Coubertin more than a century ago, sport has evolved into a global business driven by performance and records. The extensive media coverage of sporting events serves to heighten public awareness of sports and of top sports people, as well as to sustain and increase sales of sporting goods and services through aggressive branding and marketing in a highly competitive global marketplace. Athletes are now participating in increasingly complex technological systems that require much deeper understanding than they may have had in the past. The quest for new markets, records and sports supremacy has led to millions of dollars being spent on research and development of sport technique and equipment. Sport as we know it today can hardly be separated from technology. We only need to take a brief historical excursion focusing on the evolution of a sport such as cycling to realise the intensity of this inherent interdependency. For example, when Francesco Moser shattered the world cycling ''hour" record in Mexico City 20 years
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ago, he was said to be not half as good a cyclist as the previous record holder, Eddie Merckz had been (The Age, 22 February 1983). Moser rode a bike equipped with the latest technology at that time, including solid disc wheels that reduced the "egg beater" effect produced by spokes. Each component of his bicycle was tested and improved in one of the wind tunnels at the world renowned Dal Monte centre for cycling technology in Italy. He even wore a onepiece synthetic suit and leg warmers to reduce friction. At the Tour de France in 1989, a 28 year old American Greg Lemond began the final 24 km time trial stage, a total 50 seconds behind the leader, Lauren Fignon of France. Lemond decided to use for the first time a pair of clipon aerodynamic handlebars developed for triathlon racing. He made cycling history by surpassing Fignon's time by a mere 8 seconds, resulting in outright victory. "Aerodynamics cost me the Tour de France" claimed Laurent Fignon. Time trial bars were an instant success, resulting in major changes to the sport of cycling and triathlon. Subsequent tests conducted at the Texas A&M wind tunnel indicated savings of approximately 12 minutes at 25 miles per hour, when using time trial bars as opposed to cow horn style (elbows are drawn closer together, therefore decreasing the amount of turbulence and air pressure at the front of the cyclist) (Burke, 1995; Hagberg and McCole, 1990; Kyle, 1991). In recent years, Australian track cyclists won impressive victories at the world track championships and the Commonwealth Games (e.g. 1995, 1996 and 1997). The Australian team used a unique carbon fibre monocoque bicycle developed in collaboration by RMIT University and the Australian Institute of Sport (AIS). Continuous development of this much lighter and stiffer "AIS/RMIT Superbike" has allowed Australian cyclists to win over twelve world championship titles and set four world records. These marvelous sporting achievements testify as much to the importance of technology in sport as they do to the ability or will of those athletes to win. Overwhelmed by many predictions of revolutionary new technologies that are anticipated in the new millennium we should not loose sight of the fact that inventors of new technology have frequently looked to the past for inspiration (inventors of sports technology more so than others). For example, one of the greatest innovations in rowing today is the development of the sliding rowing seat. Rowing historians point to a surviving section of the Lenormant Relief on the Acropolis that shows oarsman bending his knee while taking a stroke in Greek trieres (the trieres or trireme was the stateoftheart warship of 2000 years ago designed for speed), indicating that ancient Greeks slid on their seats during rowing. The best oarsmen of the Greek fleet used their legs to drive the boat by sliding on sheepskin cushions. This concept was subsequently used in 1870's when the "modern" sliding seat was invented and widely adopted in rowing (USOC, 1998). The introduction of sliding led to a fundamental change in the way boats were rowed. The quest for speed sought to maximise the force applied to the oar handle and to use it efficiently to produce effective, repeated strokes. A sliding seat enabled the drive of the oar to be sequentially aided by forceful extension of the legs and extension of the trunk (Dudhia, 1998). Before the introduction of the sliding seat, rowing was predominantly an upper body sport. The many advantages of whole body workout made possible by the sliding seat led to the development of the modern indoor rowing machine. Today, indoor rowing has become a sport in its own right with the World Indoor Rowing Championship held annually in America since 1982. In coming to grips with the notion of sports engineering as a discipline a particular concern emerges: the dangers in assuming traditional roles and practices of
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science and engineering. It has been suggested in the introduction of this paper that consequences of technological change in sports are far reaching, and that the decisions about sports technology cannot be based only on scientific and technical considerations. This paper explores broader issues that complement science and technology in sports including history, philosophy and policy. A deeper understanding of these underpinning issues is required as a prerequisite for the development of sports technologies capable of meeting the needs of athletes and the society in general. Although, an indepth review of relevant publications has been used as a basis for this work, the treatment that follows makes no claim of completeness; it is merely an attempt to draw some conclusions that may help in defining the nature and role of sports engineering. Causes and Effects of Technological Change Many modern sports date from the earliest civilisations. For example, a crude form of hockey was played in Egypt 4000 years ago and in Ethiopia around 1000 BC. Ancient pictorial illustrations indicate that the Arabs, Greeks, Persians, Romans and the Aztec Indians of South America each had their own versions of the game (Howells, 1997). The first evidence of skiing exists also in the form of a rock drawing found in Northern Norway, dating from 2000 BC with the oldest known version of a ski found in Hoting, Sweden believed to be some 4500 years old (Lloyd, 1986). Coubertin's revival of the Olympics reestablished the discus and javelin, which first appeared in a sporting competition in 708 BC. Before ancient sports were reinvented and introduced for enjoyment and leisure (long before sport became a lucrative global business), skis, archery bows and arrows, javelins, and other artefacts were an integral part of society's requirements for hunting, transportation, work and war. Society's requirements changed and so did the nature and role of sport. In the previous century, as Edward Tenner pointed out in his book Why Things Bite Back: Technology and the Revenge Effect, coaches and scientists have rationalised professional and amateur sports with a vengeance, raising them to levels of system and performance that many other professions might envy (Tenner, 1997). The "technological revolution" in sports saw unprecedented advances in both technology and technique. New technologies that have been initially developed and trailed in the aerospace and defense industries in particular have had a profound effect on sport (e.g. new materials made sports equipment stronger, lighter and stiffer; digital, video and laser technologies have given way to new hardware and software for measuring, monitoring and analysis in sports). While new technologies have made sport faster, more powerful and enjoyable in many ways, they have also unintentionally changed the type and pattern of injury experienced by athletes. New sport techniques frequently evolved with new technology as a countermeasure for changed injury patterns. For example, the change in skiing injuries can be attributed to the evolution of this sport with the introduction of stiffer plastic boots, more responsive skis and releasable ski bindings in the late 1970's. This has led to the shift in injury location from ankles and lower legs further up the leg, at the knee (Leach, 1994). The frequency of knee sprains involving ligament tears has increased dramatically. The stiff back of the modern ski boot and the tail of the modern ski create a unique lever system not found in other human activities. The Phantom Foot (or the socalled tail of the modern ski) represents a new type of injury
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resulting from the use of modern skis. When a skier looses balance to the rear there is an instinctive tendency for the boot to push the lower leg forward causing the offbalanced posture to place additional load on the ACL (anterior cruciate ligament) and the central ridge of the tibial plateau. From the perspective of the knee, the foot is forced to rotate inward, which is not possible without a lever system acting in a direction opposite to the natural lever system – the foot. Consequently, more appropriate skiing techniques had to be developed around the new technology in recognition of the changing injury patterns (VSR, 1998). In case of American football, as opposed to skiing, sport technique has evolved to take a competitive advantage of new protective equipment (thanks to the rule allowing tackling below the waist), making in turn the sport more dangerous and injuries more severe. With the introduction of the plastic helmet in the 1950's, this sport became more brutal, coaches have devised more aggressive tactics, players were willing to take more risk and spectators were more excited about the game. But, the new style of play has more than tripled the number of neck injuries and doubled the deaths from cervical spine injuries (Gelberg, 1995). New rules and standards governing the design and manufacture of protective football helmets were enforced in order to minimise the fatal effects of impact. Technological change and its consequences have reinforced the need for a more proactive role of governing bodies and professional associations in sports. Rules governing the development and use of sports technology are multifaceted and take into consideration not only performance and safety but also broader social and political issues. They may be driven by the desire to maintain a particular sporting tradition or heritage (eg. the use of wooden bats in baseball and cricket), to maintain the existing infrastructure and avoid overperformance (eg. design limitations relating to golf clubs and balls, javelin), or to promote interest and even sexappeal (eg. prescribed use of bikini type shorts in beach volleyball). Howard Brody once told me over a lunch that the serve had "created" the modern game of tennis and that it will surely "destroy" it unless new rules are put in place to alleviate the dominance of the serve. Now, new regulations relating to the turf used in tennis courts, size and weigh of the tennis ball are being examined. The SocioEconomic Context Increasing participation in physical activity throughout the community represents a high public priority in Australia just like in many other countries in the developed world. It is generally felt that active participation in sports and leisure provides a basis for a healthier life style, which may also lead to achieving higher effectiveness in the workplace. Today, more Australians are participating in sports than ever before. According to the Australian Bureau of Statistics (ABS) almost half of all Australians aged 18 years and over participated in sport or physical activities in 19971998 (ABS, 1998). Traditionally, sports with the highest participation rate include aerobics, golf, tennis, netball, lawn balls and swimming. The causes and effects of growth and fragmentation in sports participation in the UK over the last two decades, as reported by Taylor in 1998, are consistent with those experienced in Australia. As in the UK, increased consumer spending in sport in Australia is also related to an increase in active participation. Australian households spent $27 billion on recreation and personal services in 19931994 (an increase of 33% on expenditure
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in 19891990) with nearly $6 billion spent on sport alone. This represents the fourth highest household expenditure item behind food, transport and housing (ABS, 1998). The sports products industry has diversified to accommodate the different interests and needs of the consumers, and has in many cases promoted and helped the development of new sports that would in turn require new types of equipment (e.g. snowboarding, skiboarding, inline skating etc.). From the industry's perspective, aggressive branding and marketing is aimed primarily at increasing consumer expenditure on new sports products whereby increasing sports participation is one way to achieve this. This is certainly the case in Australia, where those actively participating in sports spend most of their money on sports clothing and equipment (e.g. in 19961997 $814 million in total, with over $100 million spent on golf clothing and equipment) (ABS, 1998). The appeal of sport to the business community is almost universal and is evidenced among other things in the rate of corporate sponsorship. For example, in Australia sport attracts 10 times more corporate sponsorship than the arts, according to a national survey on business sponsorship (in the 19961997 financial year alone, a total of 22700 businesses spent $281.9 million to sponsor sport). The diversification and growing complexity of the sports products market has made us reassess what sports products are all about. It has been suggested recently that sports products comprise sports equipment (capital and personal equipment), sports clothing and sports footwear (Taylor, 1998). This classification is more inclusive than the traditional treatment of sports products through personal equipment alone. It also provides a more realistic framework for the investigation of the socioeconomic aspects of sports and leisure technology. Despite the fact that Australia today represents one of the leading sporting nations in the world, sport in Australia did not always enjoy a high profile, especially at the elite level. It took many years of Government initiative and support to bring Australian sport to the current high international standards. To achieve this goal, the Australian public was willing to accept increased sports funding despite the relatively tough economic conditions. Australia would not be able to stage the impressive national and international sporting events over the years (such as the Melbourne Olympic Games in 1956, Sydney Olympic Games in 2000, Australian Open tennis grand slam tournament, Adelaide and Melbourne Formula One Grand Prix, just to name a few) and it would not be the great sporting nation that it is without the considerable financial commitment by all stakeholders. The Australian Sports Commission (ASC), with a budget of some $92 million per year, is responsible for the implementation of the Federal Government's sport policy, including the funding and development of sport. The Commission is concerned with the development and maintenance of an effective national sports infrastructure, improved participation in quality sports activities by Australians and excellence in sports performance by Australians (ABS, 1999). Within the ASC, the Australian Institute of Sport (AIS) program is responsible for the development of elite sport on a national basis. The Australian Institute of Sport was officially opened in 1981. The need for such an Institute became obvious in particular after the dismal performance of Australia's elite athletes during the 1970's. The inability to maintain competitive standards at international level reached a crisis point following the Montreal Olympic Games in 1976 where Australia was unable to win any Gold medals. Since 1981, the AIS has been the focus for all that is involved with the preparation of elite athletes including the application of latest research in sports sciences and technology. It has become the catalyst for much needed change in servicing elite sport, which resulted in Australia
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winning XX Gold medals at the Atlanta Olympic Games in 1996. With the burning desire to do even better at the homeground Sydney Olympic Games in 2000 the Federal Government has boosted funding of elite sport even more in recent years. In the leadup to the 2000 Olympic and Paralympic Games the Government committed another $135 million ($20 million per annum from 19941995 to 19961997 and $25 million per annum from 19971998 to 19992000). Winning Gold medals has become a matter of national priority and an ingredient contributing to a higher international profile of the country. With increased participation in sport and recreation (underpinned by the international success of elite athletes and the institute model), Australia's sport and recreation industry has grown rapidly to become economically and socially very significant. It now involves over 11000 thousand businesses, and produces goods and services valued over $12 billion, according to the Australian Bureau of Statistics. These businesses employ over 160000 people and the sector contributes at least 1.2 per cent to the nation's gross domestic product, which is about the same as Australia's motor vehicle manufacturing sector (NOSARP, 1997). Research, development and innovation in sport and recreation technology have enabled Australia to boost its export potential. By the year 2000 Australia is estimated to be generating $600 million in sport and recreation goods and services exports to Asia alone. Watercraft and water sports equipment, swimwear and bicycles account for more than a third of the traded sport and recreation goods, with New Zealand, USA and Japan being the main destinations. Sports Engineering Revisited Sports engineering is not easily defined. In this emerging discipline applied scientists have frequently been employed to do what may have been thought of as "engineering work" and vice versa, engineers have conducted work traditionally undertaken by applied scientists. This paper suggested that there is one distinctive feature of sports engineering that draws together both sport science and engineering technology. Although sports engineering has embraced sports technology as its meta theme, it should not be subsumed in the term "science and technology" at the policy level as traditional professional engineering has been for many years. The issues and examples presented in this paper indicate that implications of designing and using new sports technology are much broader, and that the decisions about this type of technology are often political and social rather than just scientific or technical. Research in sports engineering has focused over the years on new technologies that can improve not only performance and enjoyment but also safety. Introduction of new technologies has frequently sparked more fundamental changes in the way sport is conducted and how athletes are coached to compete and win. Technological changes in sports have unintentionally changed the severity and pattern of injuries experienced by athletes, in some instances with dire consequences. Arguably, sports engineering must place a greater emphasis in the future on predicting the consequences of technological change in sports. It must provide a scientific basis for decisions about new sports technology by taking into account all intrinsic factors including the underpinning sport technique and governing rules. Clearly we must recognise that as in the case of almost any engineering solution, the design of new equipment for sports represents a compromise.
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References Australian Bureau of Statistics (1998). Sport and Recreation: A Statistical Overview. ABS Catalogue No. 4156.0. Australian Bureau of Statistics (1998). Participation in Sport and Physical Activities, Australia, 19971998. ABS Catalogue No. 4177.0. Australian Bureau of Statistics (1999). Australia Now: A Statistical Profile. http://www.statistics.gov.au/websitedbs/c. Bjerklie, D. (1993). HighTech Olympians. Technology Review, 96(1993). Brody, H. (1988). Tennis Science for Tennis Players. University of Pennsylvania Press, Philadelphia. Brody, H. (1997). The Physics of Tennis III. The ballracket interaction. American Journal of Physics, 65, 981987. Burke, R. E. (1995). Serious Cycling. Human Kinetics, USA. Colson, E. (1998). Avoiding Knee Pain. Bicycling Australia, Vol. 9, No. 4, pp. 6667. Dudhia, A. (1998). FAQ: Physics of Rowing. http://wwwatm.atm.ox.ac.uk/rowing/physics.html. Easterling, K. E. (1993). Advanced Materials for Sports Equipment. Chapman and Hall, London. Gelberg, J. N. (1995). The Lethal Weapon: How the Plastic Football Helmet Transformed the Game of Football, 19391994. Bull. Sci. Tech., Vol. 15, Nos. 56, pp. 302309. Gelberg, J. N. (1996). The Rise and Fall of the Polara Asymmetric Golf Ball: No Hook, No Slice, No Dice. Technology in Society, Vol. 18, No. 1, Pergamon, pp. 93110. Gelberg, J. N. (1997). The Big Technological Tennis Upset. Invention and Technology, Spring Issue, pp. 5661. Greene, N. and Raine, A. (1976). Alpine Skiing. University of Queensland Press, Queensland. Grisogono, V. (1985). Sports Injuries. John Murray Publishers, London. Guttmann, A. (1978). From Ritual to Record: The Nature of Modern Sports. Columbia University Press, New York. Hagberg, J. M. and McCole, S. D. (1990). The Effect of Drafting and Aerodynamic Equipment on Energy Expenditure During Cycling. Cycling Science, 2 (3), 20. Howells, M. K. (1997). The Romance of Hockey History. M. K. Howells. Kyle, C. R. (1991). Wind Tunnel Tests of Aero Bicycles. Cycling Science, 3, pp. 5761. Kramer, S. (1999). Simplifying the Science of Golf: You don't need a Ph.D. to understand clubs. Golf Magazine, September. Kramer, S. (1999). Playing with Fire. Golf Magazine, March. Kuessner, U. (1994). Goodbye to Tennis Elbow. Australian Tennis Magazine, Dec. Leach, R. (1994). Handbook of Sports Medicine and Science: Alpine Skiing. Blackwell Scientific, Oxford. Lloyd, J. M. (1986). Skiing into History. Brown Prior Anderson. Lycholat, T. (1996). Rowing Machines. Fitness Network, Aug/Sept. United States Olympic Committee (1998). Sports A to Z: Rowing: History. http://www.olympicusa.org/sports/az_3_26_1.html. NOSARP (1997). Sizing Up the Industry. http://www.dist.gov.au/nosarp/sizing.html.
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Robertson, M. (Ed.) (1974). The Encyclopedia of Tennis. Rainbird Reference Books, London. Taylor, P. (1998). The Economics of Sports Products Industry. In Haake (Ed.). The Engineering of Sport. Blackwell Scientific, Oxford. Tenner, E. (1997). Why Things Bite Back: Technology and the Revenge Effect. Fourth, Estate, London. Vermont Safety Research (1998). Training Tips for KneeFriendly Skiing. VSR, Underhill Centre, Vt. Williams, M. (1991). The Protective Performances of Bicycle Helmets in Accidents. Accident Analysis and Prevention, 23, pp. 119131.
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The Development of Sports Engineering around the World S.J. Haake Department of Mechanical Engineering, University of Sheffield, UK ABSTRACT: Sports Engineering is a new area of research that gained popularity at the end of the 20th century, despite being around for hundreds of years previously. The effect of sports engineering on individuals, sports and big business is analysed. For tennis, golf, pole vault and the 100 m sprint it is found that there was continual improvement over the 1900's. Only in the pole vault, however, was there a clear suggestion that technology influenced the sport significantly with increases of jump height of over 240 mm between Olympic Games after the introduction of glass fibre poles in 1964. It is suggested that the majority of improvement in sports is through improvements in coaching, training, physiology and nutrition. The claim that the sport is 'big business' is assessed and the research output in the area analysed. It was found that the research output from the US was grossly underrepresented.
Introduction Sports engineering is not a new topic by any means. Newton considered the mechanics of tennis over three hundred years ago while a mechanical line call device was in use in Real Tennis in the 1500's (Morgan, 1989). It is only recently, however, that the area of study has been given an identity; firstly through the annual conferences in Japan by the JSME (JSME, 1998) and later through international conferences held in the UK (Haake, 1996, 1998). This paper looks at how sports engineering affects athletes, sports and business and assesses the expansion of sports engineering around the world. Sports Engineering and the Athlete It is difficult to determine the exact relationship between a piece of sports technology and performance due to the variables involved in the improvement of athletic performance. There is little in the way of technology in the 100 m sprint apart from shoes and the surface. Although the latter do affect performance, it is likely that the majority of improved performance in this event over the last 100 years is due to improvements in the athlete. Figure 1 shows the winning times for the 100 m sprint at the Olympic games from 1896 to 1996. The decrease in times is levelling off so that the improvement is now approximately 6 ms yr1 compared to 15 ms yr1 in 1900
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(1896 data omitted). It is likely that the improvement is more than likely due to improvements in training, coaching, physiology and nutrition. Due to an athlete's ability to adapt, the introduction of a particular piece of apparatus may not have the effect expected of it and this can be demonstrated if the example of the polevault is taken (Wegst and Ashby, 1996). Figure 2 shows the winning heights for the polevault discipline at the Olympic games from 1896 to 1996 (gaps indicate no data due to global conflict). It can be seen from Fig. 2, that winning heights have increased from just over 3 m in 1896 to almost 6 m in 1996. Some of the increase in performance is due to coaching, changes in physiology, nutrition etc but some may be due to changes in technology of the pole. In 1896 poles were made of solid hickory wood. Bamboo poles were introduced in 1904 and were used for almost the next 50 years. By the 1950's, improvements in performance between Olympic games was minimal. A brief use of aluminium poles had little effect but a significant change can be seen in 1964 when poles made from glass fibre composites were introduced.
Fig. 1. Gold medal winning times for the men's 100 m sprint at the Olympic Games since 1896.
Fig. 2. Gold medal winning heights for the pole vault at the Olympic Games since 1896.
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These poles were lighter and less stiff than previously and allowed the athlete to change style, performing a relatively complex manoeuvre of rotating upside down to go over the bar feet first. In 1996, the height jumped had stopped increasing compared to a change of approximately 240 mm (9.4 inches) between Olympic Games in 1964. To conclude, therefore, improvements in human performance can be made through the introduction of technology, but not always in a way that is expected. The introduction of a less stiff pole in the pole vault allowed the athlete to change his technique and it was this that improved the performance rather than the technology itself. The Effect of Engineering on Sports With sports technology and sports engineering there is always a fear that the technology will produce an unwanted step change in a sport or change it so that it no longer becomes popular. Ruling bodies have been aware of this issue and have used scores as a measure of the influence of technology. The USGA studied the scores of the US PGA tour over a period of 25 years (Thomas, 1994). They found that the average winning score was improving at 1 stroke per 21 years and that the 25th placed player was improving at 1 stroke per 14.5 years. It appears, therefore, that all golfers are improving on the PGA tour but the lower placed players are slowly catching up to the best players. This could be a combination of coaching, improved physiology and equipment. Tennis has suffered in recent years from the label that it has become dominated by the serve. Critics argue that lighter rackets allow the server to swing it faster, thus allowing the ball to be served faster. Figure 3 shows the relationships between the percentage of sets ending in a tiebreak and the average first serve speed for the fourteen fastest male servers at Wimbledon, the US Open and Roland Garros, in 1999. The tiebreak data is calculated using the previous ten years of tournament data and players are only included if the total number of sets played at the tournament exceeds fifty. Only the 1999 speed values were available.
Fig. 3. Percentage of sets ending in a tiebreak at Roland Garros,Wimbledon and the US Open vs. average 1st serve speed for a sample of 14 male players.
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Fig. 4. Percentage of sets ending in a tiebreak at Roland Garros, Wimbledon, the US Open and the Australian Open since 1965.
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It can be seen from Fig. 3 that data from all the tournaments follows roughly the same trend with players with faster serves experiencing a higher percentage of tie breaks. This is probably due to at least two factors; players with a good serve are likely to progress further in the tournament thus meeting players of a similar standard; a match where the serve was dominant would cause games to be won in turn leading to a tiebreak. Although there is no historical record of serve speeds, scores exist for all games. Thus percentage tiebreaks can be monitored as an indicator of the dominance of serve speed on the game. Figure 4 shows the percentage of sets ending in a tiebreak at the French Open, Wimbledon, the US Open and the Australian Open for both men and women since 1965. It can be seen that, at all four grand slam tournaments, the men's game has a higher percentage of tiebreaks than the women's game. The fastest surface is generally accepted to be Wimbledon (grass) while the slowest is Roland Garros (clay). For the men's game, it appears that the percentage of tiebreaks is increasing with time at all tournaments which in turn implies that the serve speed is increasing and becoming more dominant. Interestingly, the issue is made more complicated by a change in style between tournament surfaces. Roland Garros is played on clay and is perceived as slowest, Wimbledon on the fastest surface, grass, with the US Open on a hard court with a speed in between. It appears that average serve speed is directly related to the surface played upon. Players may, therefore, be adapting their serve to the surface played upon, possibly applying spin more readily on slower surfaces with speed emphasised on faster surfaces. The data for the women's game is more complex and it is possible that serve speeds are not high enough to be a significant cause of tiebreaks. The issue for sports engineering is whether equipment and technology changes have been responsible for changes over time. There is no evidence of a step jump in percentage tiebreaks during the 1980's after the introduction of composite rackets. Thus, lighter rackets are not the sole reason for the increase in serve speed although they may help produce an increase in serve speed through change in technique. Whatever the case, the data indicates that, should the game proceed as it is, the average 1st serve speed at Wimbledon will be 120 mph and almost a quarter of all sets will end in a tiebreak by the middle of this century. Sports Engineering and Business There have been many claims in the media that sport is ''big business". Certainly, some estimates put the sports equipment market at $80 billion and individual companies such as Mizuno, Nike, Callaway and Decathlon easily have sales in excess of $1 billion (SGMA, 1997). Figure 5 shows the average annual expenditure (in $) of participating adults on sports equipment. In the UK, participation in sport has increased from 39% in 1977 to 64% in 1996 (defined as percentage of population participating in any sporting activity in the four weeks prior to the study; Taylor, 1998). Increases such as these would give a marked increase in turnover to companies. Although Taylor (1998) puts consumer spending on sports equipment for the UK at half that in Fig. 5, he suggested that spending has increased by £1.3 billion over a period of twenty years. The major reason, however, that sport is perceived as big business, however, is that the media is willing to pay well for it. In the US, NBC payed $4 billion to the rights the Olympic Games while in the UK, Sky payed hundreds of millions of pounds for premier league soccer.
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Fig. 5. Average annual expenditure (US$) of adult sports participants (source: SGMA world report 1997).
Sports Engineering Research around the World Figure 6(a) shows the source of papers presented and published at the 1st and 2nd International conferences on Sports Engineering and the journal Sports Engineering, from 1996 to 2000 (Haake; 1996, 1998). It can be seen that the majority of papers come from Europe with significant contributions from Asia (predominantly Japan) and North America (predominantly the USA). The numbers are biased towards Europe since much of the published sports engineering activity originates from there. Clearly North America and Asia are under represented in the research output although the reason for the latter may be language difficulties. The UK is probably the best developed country regarding research output in this area and has approximately 10 research papers per $1k of Gross Domestic Product (GDP) per head. Figure 6(b) shows the distribution of papers normalised by GDP per head of population of each country. Regarding Fig. 6(b) one comes to the inescapable conclusion that Europe is over represented (primarily due to the origin of sports engineering in the UK) while North America is grossly under represented. It can be estimated that, if the sports engineering association networks around the world were as well established as those in the UK and Japan, then the research output could be at least quadrupled.
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Fig. 6. Percentage of research papers in international publications from 1996 to 2000; (a) raw data and (b) data normalised with GDP per head taken as normal rate of population.
Conclusions This paper concludes that although sports engineering can have influence on individual athletes and on sports, the evidence for this is by no means clear. Studies show that times to run the 100 m sprint decreased during the last century, and pole vault heights have increased. Although the influence of technology on the former is unclear, it appears that changes in the design of the pole vault give a clear step jump in performance. The value of the world sports equipment market has been estimated as $80 billion and calculations show that if research output is considered, the US is grossly underrepresented compared to Europe and Asia.
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Acknowledgement Thanks to the International Tennis Federation for access to tennis data and scores. References Haake S. J. (Ed.) (1996) The Engineering of Sport, pub. Balkema, Rotterdam, pp. 343. Haake S. J. (Ed.) (1998) The Engineering of Sport – Design and Development, pub. Blackwell Science, Oxford, pp. 576. JSME Symposium on Sports Engineering, 98 (31), published by JSME, Tokyo, pp. 306. Morgan, R. (1989) Timber tennis courts of the sixteenth century, Int. J. History of Sport, 6, (3) 378388. Sporting Goods Manufacturers Association World Report, (1997), pub. SGMA, North Palm Beach, Florida, pp. 121. Taylor P. (1998) The economics of the sports products industry, The Engineering of Sport – Design and Development, (Ed. S. J. Haake), pub. Blackwell Science, 312. Thomas F. (1994) The state of the game, equipment and science, in Science and Golf II, Proceedings of the World Scientific Congress of Golf, (Ed. A. J. Cochran and M. R. Farrally), pub. E. & F. N. Spon., London, 237246. Wegst U. G. K. and Ashby M. F. (1996) Materials selection for sports equipment, in The Engineering of Sport, (Ed. S. J. Haake), pub. Balkema, Rotterdam, 175184.
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2— DESIGN AND SPORTS TECHNOLOGY
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Technology Coupling in the Design of Sports Equipment K.W. Johnson, H.R. Shercliff, M.F. Ashby Engineering Design Centre, Cambridge University, Cambridge, UK ABSTRACT: The sports equipment market is materialintensive, comparable to those of aerospace or defence. Sports equipment design, although properly conscious of risk, is largely free from the extreme constraints of safety and reliability in aerospace design. Nor is it particularly constrained by cost since professionals, as well as amateurs, willingly pay for equipment that might improve their performance. Sports goods designers have – or could have if they wished – a freedom of material and process choice almost unknown in other markets. Innovation and successful designs are stimulated by the ability of designers to gain inspiration and knowledge from products other that those for which they are designing. The research reported here explores the possibilities for innovation that develop by searching across all sports equipment market sectors for parallel solutions to particular design problems. A sports products database, CESSports, has been assembled using an extension of the Cambridge Engineering Selector (CES) software system. CES includes extensive databases of properties for materials, processes and shapes. CESSports couples these to databases containing performance objectives, material and process applications, technical and aesthetic information, and product design profiles for sports equipment. The prototype system will be illustrated by drawing on the following equipment couples to which we have given particular attention: golf clubs and fishing poles, snowshoes and tennis racquets, ice axes and fishing hooks, surfboards and skis.
Innovation and Information The world of the designer of sports equipment is constantly driven by innovation; and, innovation derives from information and creativity. This paper looks at ways of guiding the designer through sports equipment design and channels the information that surrounds it; in this way, we hope to enable innovations. Methods of Creativity Faste [Faste (1995)], in writing on the role of aesthetics in engineering, says: ' . . . insights based on the raw material of the senses are the key to creativity'. In the case of sports equipment, insights, and therefore creativity, frequently derive from
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the raw material itself. For this reason, we have chosen to focus on the use and knowledge of material technologies that are available to the sports equipment designer. Understanding the attributes and limitations of a material leads us towards creative solutions. In design, creative ideas for one product often come from a completely unrelated product: from cellular phones to coffee makers, from automobiles to stereo speakers, from paperclips to computers. In the past, developments–particularly material developments–in aerospace have stimulated the design of new, creative products in sports equipment; this is a process one might describe as technology coupling. The sports equipment market is very diverse, specialised and fragmented into parts that, in some cases, are isolated. It is our view that these parts often share common problems and goals, and that technology coupling with the sports equipment market could stimulate creativity. In this paper we explore the benefits and inspirations that can come from technology coupling. Technology coupling, explained later in full detail and with case studies, involves matching product design profiles of similar design intent and relevant technologies. To retrieve adequate results from comparisons of a pair of products with similar design issues we have developed a product design profile for each. The Product Design Profile A start has been made on constructing a database of sports equipment, creating an attribute profile of each–a product design profile. We have sought examples spanning a wide variety of sports, including examples of the following: • Sports driven by advanced material technology (e.g. tennis, golf) • Traditional sports that have recently adopted new material technology (e.g. snowshoes) • Minority sports (e.g. real tennis); Popular sports (e.g. skiing, running) • Sports which place a high premium on safety (e.g. climbing) • A broad range of product functions (e.g. hitting a ball, floating on water, walking on snow, catching fish) The product design profile captures information about each example of sports equipment at a level of detail and abstraction that enables technology coupling, in the way described later. Fig. 1 shows an example of such a profile; it includes information about design intent, material, process and the combinations of material properties that determine performance (the 'performance indices).
Page 23 Product Name
Surfboard: The Wave 99
Product Family
board
Price
£300
Weight
500 g
Scale
1 m
Sport
surfing
Design Intent
buoyancy, stiffness to weight (plate in bending)
Materials
current polymer foams; historical wood
Processes
composite forming, sandwich construction
Indices: Material Properties
water absorption, E,
Indices: Performance Indices
E1/3/
Fig. 1 Example product design profile for a surfboard.
The Material of Sport: The Sport of Material A review of technical and academic articles published in The Engineering of Sport from 1996 to 1998 [Haake (1996,1998)] suggests key questions about the use of materials and process (or material technologies) in sports equipment. Material technologies, for the rest of this paper, and in earlier work [Johnson, et al. (1999)], are defined as any material, process or materialprocess combination. • Why are natural materials so widely used, and must synthetic materials exactly imitate natural materials? • How many chances does a new material have for introduction before it is a failure? • Why is there a dominance of composites? • Can we prevent injury with material developments? • Are first order models of performance enough for initial material selection? • Are materials chosen for technical or aesthetic reasons? • Is there a danger that processes, without understanding, become 'art', e.g. cricket bat rolling? • How comparable is equipment that shares similar material or process technologies or design targets? • What's the next big thing – the next titanium? Given these questions, a methodology for technology coupling is outlined below; the CESSports system enables this methodology. A Methodology for Technology Coupling Design intent, and the associated material properties and performance indices are important abstractions in technology coupling. They, and other important product attributes, are found in the following way.
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(1) Identify the function of the product. Is it a beam in bending, like a rowing oar? Does it transfer energy, like a golf club? Does it absorb energy, like a cricket glove? Does it provide protection from impact, like a climbing helmet? Does it store energy like a spring, like an archery bow? (2) Use this function to link your product to a list of relevant design intents: stiffnesstoweight (of a panel in bending), energy transfer, vibration control, impact resistance, etc. (3) In detail, for each product selected to complete a couple, consider the constraints, objective(s) and material indices; this is required so that the validity and intensity of the design intent link is clear. • Identify the mechanical constraints on the product. The product should carry a design load (and overload) without failure; there is a requirement of sufficient fracture toughness to avoid cracking, chipping or spalling; the surface must be hard enough to withstand indentation loads. • Identify the biomechanical constraints on the product. Is there a limit to the force required by the user, like the draw force for an archery bow? Are there specific restoring or supporting forces related to body mass, like for a vaulting pole? Are there geometric constraints imposed by the human body, such as the crank length of a bicycle? • Identify the objective(s) to maximise or minimise. Minimise mass, as is the objective for a rowing shell; maximise velocity, as for a racing bicycle; minimise friction, as for rollerblades; maximise energy transfer, as for an archery bow. For most products we also seek to minimise cost. • Identify key material indices: material property constraints and performance indices. Simple constraints on a property, P, take the form A