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Introduction to Sports Biomechanics

Other titles available from E & FN Spon Kinanthropometry and Exercise Physiology Laboratory Manual Tests, procedures and data Edited by Roger Eston and Thomas Reilly Drugs in Sport 2nd edition David Mottram Foods, Nutrition and Sports Performance Edited by Clyde Williams and John R Devlin Notational Analysis Mike Hughes and Ian Franks Physiology of Sports Thomas Reilly, Peter Snell, Clyde Williams and Nils Secher Science and Racket Sports II Edited by Adrian Lees, Mike Hughes, Thomas Reilly and Ian Maynard Science and Soccer Thomas Reilly Sport, Leisure and Ergonomics Edited by Greg Atkinson and Thomas Reilly Visual Perception and Action in Sport Mark Williams, Keith Davids and John Williams Journal of Sports Sciences Editor: Roger BartlettFor more information about these and other titles published by E & FN Spon, please contact: The Marketing Department, E & FN Spon, 11 New Fetter Lane, London EC4P 4EE Tel: 0171 583 9855; Fax: 0171 842 2303; or visit our web site at www.efnspon.com

Introduction to Sports BiomechanicsRoger Bartlett

First published 1997 by E & FN Spon, an imprint of Chapman & Hall This edition published in the Taylor & Francis e-Library, 2002. 1997 Roger Bartlett All rights reserved. No part of this book may be reprinted or reproduced or utilized in any form or by electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloguing in Publication Data Catalog Card Number: 9667515 ISBN 0-203-47616-6 Master e-book ISBN ISBN 0-203-78440-5 (Adobe eReader Format) ISBN 0-419-20840-2 (Print Edition)

To my dearest Mel

Contents

Preface Permissions Part One Foundations of Biomechanics Introduction 1 Anatomical principles 1.1 Movements of the human musculoskeletal system 1.1.1 Introduction 1.1.2 Planes of movement 1.1.3 Axes of movement 1.1.4 Movements in the sagittal plane about the frontal axis 1.1.5 Movements in the frontal plane about the sagittal axis 1.1.6 Movements in the horizontal plane about the vertical axis 1.1.7 Other movements 1.2 The skeleton and its bones 1.2.1 Introduction 1.2.2 Bone composition and structure 1.2.3 Types of bone 1.2.4 The bone surface 1.2.5 Bone growth 1.2.6 Bone fracture 1.3 The joints of the body 1.3.1 Introduction 1.3.2 Dense connective tissue 1.3.3 Cartilage 1.3.4 Bursae, tendon sheaths and synovial membrane 1.3.5 Formation of joints 1.3.6 Classification of synovial joints 1.3.7 Joint stability and mobility 1.4 Muscles 1.4.1 Introduction 1.4.2 Muscle structure 1.4.3 Naming muscles 1.4.4 Structural classification of muscles 1.4.5 Types of muscle contraction 1.4.6 Group action of muscles

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1.5 The mechanics of muscular contraction 1.5.1 Introduction 1.5.2 A functional model of skeletal muscle 1.5.3 The mechanics of muscular contraction 1.5.4 Development of tension in a muscle 1.5.5 Muscle force components and the angle of pull 1.6 Summary 1.7 Exercises 1.8 References 1.9 Further reading 2 Movement (kinematic) considerations 2.1 Fundamentals of kinematics 2.1.1 Introduction 2.1.2 Types of motion and appropriate models 2.1.3 Introduction to vectors and scalars 2.2 Further exploration of linear kinematics 2.2.1 Obtaining velocities and accelerations from displacements 2.2.2 Interpretations of graphs of kinematic data 2.2.3 Obtaining velocities and displacements from accelerations 2.3 Projectile motion 2.3.1 Projection parameters 2.3.2 Optimum projection conditions 2.4 Rotational kinematics 2.4.1 Introduction 2.4.2 Angular motion vectors 2.4.3 Velocities and accelerations caused by rotation 2.4.4 Rotations in three-dimensional space (spatial rotations) 2.5 Summary 2.6 Exercises 2.7 Appendix: Component addition of vectors 2.8 References 2.9 Further reading 3 Linear and angular kinetics 3.1 Basics of linear kinetics 3.1.1 Forcesdefinition and types 3.1.2 Systems of forces and equilibrium 3.1.3 Momentum and Newtons laws of linear motion 3.1.4 Determination of the centre of mass of the human body 3.2 Friction 3.2.1 Types of friction 3.2.2 Reducing friction 3.2.3 Increasing friction 3.2.4 Starting, stopping and turning

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3.2.5 Effects of contact materials 3.2.6 Pulley friction 3.3 The impact of sports objects 3.3.1 The nature of impact 3.3.2 Direct impact and the coefficient of restitution 3.3.3 Oblique impact 3.3.4 Instantaneous centres of rotation and the centre of percussion 3.4 Fundamentals of rotational kinetics 3.4.1 Moment of inertia 3.4.2 Laws of rotational motion 3.4.3 Angular momentum of a rigid body 3.4.4 Angular momentum of a system of rigid bodies 3.4.5 Generation of angular momentum 3.4.6 Interpretation of planar sports motions 3.5 Spatial rotation 3.6 Summary 3.7 Exercises 3.8 References 3.9 Further reading 4 Fluid mechanics and energetics 4.1 Moving through a fluid 4.1.1 Viscosity 4.1.2 Fluid kinematics 4.1.3 Basic equations of fluid motion 4.1.4 Non-dimensional groups 4.1.5 Types of fluid flow 4.2 Forces in a fluid 4.2.1 Drag forces 4.2.2 The swing of a cricket ball 4.2.3 Lift forces 4.3 Fundamentals of energetics 4.3.1 Forms of energy 4.3.2 Conservation of mechanical energy 4.3.3 Important concepts related to the energetics of the sports performer 4.3.4 Forms of energy transfer 4.3.5 A trampolinist in contact with a trampoline 4.3.6 The equations of energy conservation 4.3.7 The non-steady-flow energy equation 4.3.8 Some applications of the non-steady-flow energy equation 4.3.9 Efficiency

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4.3.10 Muscles as thermodynamic systems 4.4 Energy transfers in sports motions 4.4.1 Energy transfer rates 4.4.2 Passive energy transfers and human performance 4.5 Summary 4.6 Exercises 4.7 References 4.8 Further reading Part Two Techniques for Recording and Analysing Sports Movements Introduction 5 Cinematography and video analysis 5.1 The use of cine and video analysis in sports biomechanics 5.1.1 Introduction 5.1.2 Levels of biomechanical analysis of sports movements 5.2 Recording the movement 5.2.1 Cine or video? 5.2.2 Recording the imagecameras and lenses 5.2.3 Displaying the imagecine projectors and video players 5.2.4 Obtaining body coordinates 5.2.5 Two-dimensional or three-dimensional analysis? 5.2.6 Problems and sources of error in motion recording 5.3 Experimental procedures 5.3.1 Two-dimensional recording procedures 5.3.2 Three-dimensional recording procedures 5.4 Data processing 5.4.1 Data smoothing, filtering and differentiation 5.4.2 Body segment inertia parameters 5.4.3 Segment orientations 5.4.4 Data errors 5.5 Summary 5.6 Exercises 5.7 References 5.8 Further reading 6 Force platforms and external force measurement 6.1 Introduction and equipment considerations 6.1.1 General equipment considerations 6.1.2 The detector-transducer 6.1.3 Signal conditioning and recording 6.1.4 Operational characteristics of a force platform system 6.2 Experimental procedures 6.2.1 General

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6.2.2 Calibration 6.3 Data processing 6.4 Examples of the use of force measurement in sports biomechanics 6.5 Summary 6.6 Exercises 6.7 References 6.8 Further reading 7 Electromyography 7.1 Introduction 7.2 Experimental considerations 7.2.1 Recording the myoelectric (EMG) signal 7.2.2 EMG electrodes 7.2.3 Cables 7.2.4 EMG amplifiers 7.2.5 Recorders 7.2.6 Experimental procedures 7.3 Data processing 7.3.1 Temporal processing and amplitude analysis (time domain analysis) 7.3.2 Frequency domain analysis 7.4 EMG and muscle tension 7.4.1 Isometric contractions 7.4.2 Non-isometric contractions 7.5 Summary 7.6 Exercises 7.7 References 7.8 Further reading Other techniques for the analysis of sports movements 8.1 Single-plate photography 8.2 Automatic tracking opto-electronic systems 8.3 Electrogoniometry 8.4 Accelerometry 8.5 Pressure measurement 8.6 Measurement of muscle force and torque 8.6.1 Direct measurement of muscle force 8.6.2 Isokinetic dynamometry 8.7 Summary 8.8 Exercises 8.9 References 8.10 Further reading

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Index

Preface

Sports biomechanics uses the scientific methods of mechanics to study the effects of various forces on the sports performer. It is concerned, in particular, with the human neuromusculoskeletal system. It also considers aspects of the behaviour of sports implements, footwear and surfaces where these affect performance or injury. It is a scientific discipline that is relevant to all students of the exercise and sport sciences, to intending physical education teachers and to all those interested in sports performance and injury. This book is intended as the first of two volumes covering aspects of sports biomechanics from first-year undergraduate to postgraduate level. The content of this volume mostly applies to first-and second-year undergraduate level. The focus is largely practical in approach, reflecting the nature of the discipline, and Part Two deals in detail with