Table Of ContentBiomechanics
of
Sport
Editor
Christopher L. Vaughan, Ph.D.
Associate Professor of Bioengineering
Clemson University
Clemson, South Carolina
0
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PREFACE
Biomechanics may be considered as the science that studies the external forces acting on
the human b ody a nd t he e ffects p roduced b y these f orces. Sport i s o ne a rea w here a k nowledge
of biomechanics could be of vital importance. This applies both to the improvement of
performance and to the etiology and thus prevention of s ports-related injuries.
Although biomechanics research, and specifically research on sport, has been carried out
for many decades, the formation of n ational and international bodies is of c omparatively
recent origin. The Journal of Biomechanics was launched in 1968, while the International
Society of Biomechanics, after a number of biannual congresses, was officially constituted
in 1973. This has been followed by societies being set up in the U.S. ( 1977), Canada ( 1980),
and Europe (1980) . The latest development has been the introduction of t he International
Journal of S port Biomechanics, which first appeared at the beginning of 1985. All these
societies and journals play a major role in disseminating knowledge on biomechanics, and
particularly as this knowledge pertains to sport.
The present volume is complementary to the activities of t he societies and journals. It i s
hoped that it will not only provide a basis of k nowledge, but also act as a stimulus for
further progress. Since there are many different sports practiced worldwide, the volume
quite obviously has had to be selective. This has been dictated by two main factors: a
sufficient body of research knowledge for a particular sport, and the availability of authors.
Thus, a selection of i mportant topics has been chosen. However meaningful the title and
their topics seem to be, the eventual value of t he volume is to a large extent determined by
the value of t he separate contributions. I therefore wish to thank and acknowledge all the
authors for their hard work, because without their cooperation, this volume would never
have been published. It is my fervent hope that their efforts will be rewarded by inspiring
those already in the field of sports biomechanics, or perhaps those wishing to join, to extend
our knowledge in this exciting field.
In Chapters 1 to 4, the cyclic activities are covered. In Chapter 1, the authors address
some of t he substantive issues in running. Swimming (in Chapter 2) is discussed from the
vantage point o f the forces (both propulsive and resistive) acting both on animals and humans.
Another aquatic sport, rowing and sculling, is covered in Chapter 3. Subsequently, the
biomechanics of s peed skating are reviewed in Chapter 4 from a modeling perspective. In
Chapters 5 to 9, a variety of d ifferent sports activities are covered. In Chapter 5, the use
of weights (machines, training, and lifting) is extensively and critically analyzed. The
throwing events in track and field (shot, discus, and javelin) are studied in Chapter 6. In
Chapter 7 , t he emphasis is placed on developing training programs for ski-jumping, alpine
and c ross-country s kiing a nd a lso N ordic c ombination s kiing. The m echanics o f tennis s trokes
and equipment are reviewed in Chapter 8, while in Chapter 9, t he mechanics of c ycling are
analyzed.
The publication of t his volume could not have been achieved without significant contri
butions from various individuals and institutions. It therefore gives me great pleasure to
acknowledge the following: the authors, without whom the volumes would not exist; CRC
Press, and particularly Marsha Baker, for their patience when deadlines were continually
being extended: Groote Schuur H ospital and the University of Cape Town f or providing me
with the necessary facilities and time; the Association o f Sports Science and Medical Research
Council of South Africa, for providing financial assistance; Carien Coetzee for her substantial
secretarial assistance; and my family who endured many hours of w ork, but provided en
couragement when it was most needed.
Kit Vaughan
THE EDITOR
Christopher L. (Kit) Vaughan, P h.D., is a graduate o f Rhodes University, South Africa,
with a B.Sc. in Physics and Applied Mathematics (1974). In 1975 he completed the B.Sc.
(Hons) degree in these subjects and wrote his thesis on a biomechanical model of running.
After working as a research officer at the Applied Physiology Laboratory of t he Chamber
of Mines in Johannesburg ( concentrating o n heat-exchange p roblems in exercise), he enrolled
as a student at the University of I owa. There he majored in biomechanics, anatomy, and
exercise physiology, obtaining his Ph.D. degree in 1980 with a dissertation entitled "An
optimization approach to closed-loop problems in biomechanics". While at Iowa, he acted
as a consultant to the Nissen Corporation with emphasis on weight training and trampoline
equipment.
Between 1980 and 1986, Dr. Vaughan was on the joint staff o f G roote Schuur Hospital
and the University of C ape Town Medical School in the Department of B iomedical Engi
neering. There he held the titles of Specialist Medical Scientist (Biomedical Engineer) and
Senior Lecturer. During this period he initiated and taught a course on the biomechanics of
sports techniques and injury mechanisms to candidates for the B.Sc. (Medicine) (Hons)
degree in Sports Science. In 1983, Dr. Vaughan spent his sabbatical leave as a Research
Associate at the University of O xford Orthopaedic Engineering Centre in England concen
trating on j oint forces during human walking. Since October 1986 he has been an Associate
Professor in Clemson University's Department of B ioengineering, where he is responsible
for orthopedic b iomechanics a s well as being the academic c oordinator f or the Bioengineering
Alliance of S outh Carolina.
Dr. Vaughan has published in major international journals on a variety of t opics. These
have included the fields of both orthopedic and sports biomechanics. He is a charter member
of t he American Society of B iomechanics, and since 1979 he has attended, and presented
papers at, the biannual congress of t he International Society of B iomechanics.
CONTRIBUTORS
Antonio Dal Monte, M.D. John W. Kozey, M.Sc.
Head Director of R esearch
Department of P hysiology and Orthopaedic and Sports Medicine
Biomechanics Clinic of N ova Scotia
Institute of S ports Science Halifax , Canada
Italian National Olympic Committee
Rome, Italy R. Bruce Martin, Ph.D.
Professor and Director
R. W. De Boer, M. Sc. Orthopaedic Research Laboratory
Department of E xercise University of C alifornia at Davis
Physiology and Health Davis, California
Academic Medical Centre
Amsterdam, The Netherlands Dirk J . P ons, M. Sc.
Research Associate
G. De Groot, Ph.D. Department of B iomedical Engineering
Department of E xercise University of C ape Town
Physiology and Health Medical School Observatory
Academic Medical Centre Cape Town, S. Africa
Amsterdam, The Netherlands
Carol A. Putnam, Ph.D.
Bruce C. Elliott, Ph. D. Assistant Professor
Senior Lecturer School of P hysical Education
Department of H uman Movement Dalhousie University
and Recreation Studies Halifax, Canada
University of W estern Australia
Perth, Australia Gert J . van Ingen Schenau, Ph. D.
Department of F unctional Anatomy
John Garhammer, Ph. D.
Faculty of H uman Movement Sciences
Associate Professor
Free University
Departmentof Physical Education
Amsterdam, The Netherlands
California State University
Long Beach, California
Christopher L. Vaughan, Ph. D.
Associate Professor of B ioengineering
Mont Hubbard, Ph. D.
Clemson University
Associate Professor
Clemson, South Carolina
Department of M echanical Engineering
University of C alifornia at Davis
Davis, California Kazuhiko Watanabe, M. D.
Associate Professor
Andrzej Komor, Ph. D. Laboratory of P hysiology
Department of B iocybernetics and Sports Biomechanics
Institute of S port University of H iroshima
Warsaw, Poland Hiroshima, Japan
TABLE OF CONTENTS
Chapter I
Substantive Issues in Running . ..... ...................................................... I
C. A. Putnam and J . W. Kozey
Chapter 2
Swimming: Forces on Aquatic Animals and Humans .................................... 35
R. Bruce Martin
Chapter 3
Rowing and Sculling Mechanics ........ ................................................ 53
A. Dal Monte and A. Komor
Chapter 4
Biomechanics of S peed Skating ............ ............ ............ .. .... .............. I 2I
G. J. van lngen Schenau, R. W. De Boer, and G. De Groot
Chapter 5
Weight lifting and Training ......................................... ................... I69
J. Garhammer
Chapter 6
The Throwing Events in Track and Field ............................................... 213
M. Hubbard
Chapter 7
Ski-Jumping, Alpine-, Cross-Country-, and Nordic-Combination Skiing ............... 239
K. Watanabe
Chapter 8
Tennis Strokes and Equipment . ....... ................................................. 263
B. C. Elliott
Chapter 9
Mechanics of Cycling .................................................................. 289
D. J. Pons and C. L. Vaughan
Index .... .. ................................................. ........... .............. ... 317
I
Chapter I
SUBSTANTIVE ISSUES IN RUNNING
Carol A. Putnam and John W. Kozey
TABLE O F CONTENTS
I. Introduction .. ........ ............ ..................... ....................... .... . 2
II. Running Efficiency .................................. ............... .............. 2
A. Measuring Mechanical Work Done . .... ... ........ ....... .... ...... ....... 3
I. Work Done by Internal Forces . ... ... .. .. ..... .............. .. . .. .. 3
2. Work Done by External Forces ... . .. .. ........ .. .... .. ........ .. .. 5
B. Interpreting Mechanical Efficiency ........................................ 5
I. Work Done by RJMs vs. Individual Muscles . ...... . .... ...... .. .. 5
2. Type of Muscle Contraction ....................................... 5
3. Storage and Reutilization of E lastic Energy . ........ .... ... ........ 6
4. Nonmuscular Force Contribution to RJMs ................... ...... 7
C. Muscular Effort ........................................................... 7
D. Apparent Efficiency ....................................................... 7
E. Summary ................. ................................................. 7
III. Running Economy ... ............................................................. 8
IV. External Forces .... .... ... .... .................... ... .. ........... .. .. ..... ....... 9
A. Air Resistance . ............................................................ 9
B. Ground-Reaction Force ... .. ............... .. .. .... ....... .... ..... .. .... 1 0
V. Muscle Function in Running ..................................................... II
A. Resultant Joint Moment Patterns .... ..................................... II
I. Hip Moment ....................... ............................... 13
2. Knee Moment. .... . . .. . . . .. ...... .. ...... ......................... 1 3
3. Ankle Moment ........... ........ ............................... .. 14
4. Summary ......................................................... 14
B. Functional Significance of RJMs and Segment Interaction ............... 14
C. Simulation of Running Gait .............................................. 1 6
D. Electromyography ............. ..... ...................................... 1 6
1. Hip Musculature .................................................. 17
2. Knee Musculature ..................... ............................ 17
3. Ankle Musculature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4. Co-contraction ................. ................................... 19
E. Muscle Length Changes .................................................. 19
VI. Performance Improvement ....................................................... 20
VII. Running Injuries ...................................................... ....... .... 2 1
A. Sports Medicine .......................................................... 21
1. Patello-Femoral Syndrome . ....................................... 2 2
2. Achilles Tendinitis . ............................................... 23
3. Hamstring Strains . ................................................ 23
2 Biomechanics of Sport
B. Biomechanical Measurement and Injuries ................. ........ ....... 24
1. Force Platform Data ......... .......... .. ....... .... ...... ..... ... 24
2. Pressure Transducer Data . ........ .............................. .. 25
3. Electrogoniometer Data .. ...................... ....... .......... .. 26
4. Accelerometer Data . ...... ........................................ 26
VIII. Summary ................... ..................................... .......... ...... 27
References . .. .. ........................... ........ .. ............. ... ... .. .. .... ... .... .. . 2 8
I. INTRODUCTION
Running h as r eceived c onsiderable a ttention f rom researchers i n b iomechanics, particularly
over the last several decades. The number of publications or presentations at scientific
meetings escalates yearly, adding to the more than 600 reported studies dealing with me
chanical aspects of r unning. In addition, biomechanical considerations of r unning are being
featured in popular journals with increased frequency, attempting to satisfy the curiosities
of t housands of r ecreational and competitive runners about the mechanical implications and
effects of r unning.
Consistent with the proliferation of l iterature in this area, several extensive reviews have
been published. '·4 The p resent paper is written t o augment and update these reviews a lthough
some overlap will necessarily exist.
Research into the biomechanics o f r unning is suffering the growing pains of b eing dom
inated by descriptive studies. While recognizing the importance of a n extensive descriptive
foundation, several investigators257 have emphasized the importance of a ddressing more
•
mechanistic issues - What fundamentally dictates the way we run? What forces are re
sponsible for observed running patterns? What criteria dictate optimal performance? What
are the mechanisms of i njury? - etc. In the present paper we will attempt to review the
literature on running mechanics in light of p otential answers to t h ese questions.
In the 1920s a nd 1930s, several papers, considered b y m any t o b e c lassics, were p ublished
which dealt with some of t he basic, mechanistic aspects of r unning.8 11 It is encouraging
-
that the attention of p resent day researchers is being directed more and more towards these
issues. Through these efforts we should start to see the development of a theoretical frame
work out of w hich should emerge general biomechanical principles relating to the funda
mental mechanisms of h uman motion. 12
It is impossible to understand fully the fundamental mechanisms of r unning from a bio
mechanical perspective without crossing over into several disciplines, including cardiovas
cular p hysiology, neuromuscular p hysiology, anatomy, and motor c ontrol. Space c onstraints
make it impossible to span these areas in the present review so that the discussion will be
restricted to a mechanical perspective o f r unning. The r eader i s directed t o a n excellent b ook
recently brought out by McMahon13 entitled Muscles, Reflexes, and L ocomotion, in which
many aspects critical to the fundamental understanding of running are presented in an
integrated and lucid manner.
II. RUNNING EFFICIENCY
If o ne questioned runners or r esearchers interested in the mechanics of r unning on what
fundamentally d ictates t he w ay w e r un, the answer w ould p robably b e efficiency. Efficiency,
3
defined as the ratio of mechanical work done to metabolic energy expended 13 14 is one of
•
the most extensively researched, yet poorly understood concepts of r unning mechanics. The
problem o f measuring e fficiency is one that r equires c lose c ooperation b etween biomechanists
and exercise physiologists, and is complex from both perspectives. 2 15 For the biomechanist,
•
the challenge lies in correctly measuring mechanical work done and interpreting this measure
in light of u nderlying principles which are likely to govern the way we run.
A. Measuring Mechanical Work Done
There is considerable confusion as to how mechanical work done should be measured.
Much of t his confusion stems from the fact that work done has been quantified in terms of
energy changes. As will be pointed out below, this has resulted in both ambiguous and
inaccurate measures of mechanical work done in running and consequently running effi
ciency.
Several investigators have measured mechanical work done in running solely in terms of
the work done to cause changes in the energy state o f t he total body mass center. 1 625 Winter26
-
criticized t his approach in that it oversimplified t he system, and he suggested that t he findings
of t hese studies should be regarded with caution. He pointed out that consideration must be
given to the mechanical energy changes of i ndividual segments which are collectively re
sponsible for changes in the energy state of t he total body mass center. He emphasized that
by doing this, the mechanical energy associated with reciprocal actions of b ody segments,
which have no net effect on the motion of t he total body center of m ass, are not ignored .
One o f t he first attempts to account for mechanical energy changes of i ndividual segments
in running was by Fenn.1027 He suggested that the mechanical work done on a runner was
•
the sum of t he work done to cause changes in the energy of t he total body center of m ass
(potential energy and kinetic energy due to translation), generally referred to as external
work, and the work done to cause mechanical energy changes of individual body segments
(potential energy and kinetic energy due to translation and rotation), generally referred to
as internal work. This technique has since been employed in several investigations of r un
ning. 2833 This method of analysis treats segment motions as if they were independent of
-
each other and of the movement o f the total body mass center, which is clearly inappropriate.
The body must be viewed instead as a constrained, linked system. As a result, the work
done on the human body cannot be measured by changes in energies of i ndividual segments
and/or the total body mass center in the general case. 3 4
Measures of mechanical work done on the human body require the identification of
individual forces which actually do work on the system and a quantification of t he work
done by these forces. Forces doing work on the human body system in running include those
which arise from both internal and external sources.
1. Work Done by Internal Forces
Internal forces applied to individual body segments include those exerted by muscles (or
musculotendinous units), ligaments, joint capsules, and articulating surfaces. Since it is
impossible to quantity these forces individually, 35 they are represented by a resultant joint
force (RJF) and a resultant joint moment (RJM) associated with each joint of t he system.
An RJF is the vector sum of a ll forces applied across or through a joint (including muscle,
ligament, joint capsule and bony contact forces), while an RJM is the vector sum of t he
moments of t hese forces measured relative to the joint center. Simplified in this manner,
the kinetics of the linked segment system can then be solved via an inverse dynamics
approach.
The only internal forces that are associated with metabolic energy consumption are those
exerted by muscles. The net effect of m uscle forces acting on a system of b ody segments
are reflected primarily by the RJMs of t he system. It m akes sense, therefore, that work done
by internal forces be calculated in terms of t he work done by the RJMs only. This was done
