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Beam, William Cloice
THE INFLUENCE OF BODY COMPOSITION, AEROBIC CAPACITY AND MUSCULAR STRENGTH ON THE INCIDENCE OF INJURY IN ATHLETICS
The Ohio State University PH.D. 1982
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University Microfilms % International
THE INFLUENCE OF BODY COMPOSITION,
AEROBIC CAPACITY AND MUSCULAR STRENGTH
ON THE INCIDENCE OF INJURY IN ATHLETICS
DISSERTATION
Presented in Partial Fulfillment of the Requirements for
the Degree Doctor of Philosophy in the Graduate
School of The Ohio State University
by
William C. Beam, B, A., M.A.
* * * * *
The Ohio State University
1982
Reading Committee: Approved bv
Robert L, Bartels, Ph.D.
Edward L, Pox, Ph.D. idviser Robert N, Clark, M.D. School of Health, Physical Education and Recreation DEDICATION
To my wife, Teresa, whose love and enthusiasm
made this work possible. ACKNOWLEDGEMENTS
I would like to express my sincerest appreciation to my adviser and friend, Dr. Robert L. Bartels, for his assistance and guidance throughout my doctoral program. It was through his efforts and the opportunities he created that I was able to complete and enjoy my graduate study. I am also appreciative of the efforts of Dr, Edward
L. Fox and Dr. Robert N. Clark for their guidance and advice as members of my reading committee.
If it were not for the support of my parents, Dr. William C. and Thyra Beam, my academic experience would not have been possible.
For this I am sincerely grateful, but especially I am grateful for their love. VITA
15 May 1955...... B o m - Orrville, Ohio
1977 ...... B.A. , Biology, The College of Wooster, Wooster, Ohio
1979-1980 ...... Graduate Research Associate, Department of Athletics, The Ohio State University, Columbus, Ohio
1979 ...... M.A., Physical Education, The Ohio State University, Columbus, Ohio
1980-1981 ...... Graduate Research Associate, Department of Surgery, The Ohio State University, Columbus, Ohio
1981-1982 ...... Graduate Research Associate, Departments of Surgery and Athletics, The Ohio State University, Columbus, Ohio
PUBLICATIONS
Beam, W.C., R.L. Bartels, and R.W. Ward. The Relationship of Isokinetic Torque to Body Weight and to Lean Body Weight in Athletes. Medicine and Science in Sports and Exercise 14(2): 178, 1982. TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS...... iii
VITA ...... iv
LIST OF TABLES ...... vii
CHAPTER
I. INTRODUCTION ...... 1
Statement of the P r o b l e m ...... 4 Purpose of the Study ...... 5 Delimitations of the Study ...... 5 Limitations of the Study ...... 6
II. REVIEW OF LITERATURE ...... 8
The Influence of Physical Activity on Certain Physical and Physiological Variables ..... 9 The Influence of Certain Physical and Physiological Variables on the Incidence of Athletic Injury . . 13 The Influence of Modifying Certain Physical and Physiological Variables on the Prevention of Athletic Injury ...... 19
III. RESEARCH DESIGN AND PROCEDURES ...... 22
Research Design ...... 22 Evaluation of Body C o m p o s i t i o n ...... 27 Evaluation of Aerobic C a p a c i t y ...... 31 Evaluation of Muscular Strength ...... 36
IV. RESULTS...... 39
Incidence of Athletic injuries ...... 39 Comparison of Injured and Uninjured Athletes . . . 45 Correlation of Variables with Injury Frequency . , 53 Correlation of Variables with Injury Occurrence . . 55
v V. DISCUSSION...... 65
Incidence of Athletic injuries ...... 65 Comparison of Injured and Uninjured Athletes . . . 69 Correlation of Physical and Physiological Variables with Injury ...... 72
VI. SUMMARY AND CONCLUSIONS ...... 75
BIBLIOGRAPHY ...... 78
APPENDIXES ...... 85
A. Ergo-Pneumotest Calibration Procedure ...... 85
B. Isokinetic Dynamometer Calibration Procedure .... 90
C. Raw Data of Subjects by Team ...... 97
D. Statistics 10 5
vi LIST OF TABLES
TABLE Page
1. The Influence of a Preseason Conditioning Program on the Number and Severity of Knee Injuries from 1969-1980 20
2. Physical Characteristics of Subjects by Team.... 24
3. Physical and Physiological Variables Evaluated in this Study ...... 25
4. Treadmill Protocol used for Determination of Maximal Oxygen Consumption ...... 32
5. Procedure used for the Determination of Isokinetic Muscular Strength for the Extensors and Flexors of the Knee Joint 37
6. Total Injury Rate (TINJRATE) Ranked by Team ....40
7. Lower Injury Rate (LINJRATE) Ranked by Team ....41
8. Total Injury Probability (TINJPROB) Ranked by Team . . 43
9. Lower Injury Probability (LINJPROB) Ranked by Team . . 44
10. Body composition Characteristics of Male Subjects Classified as Injured or Uninjured ...... 46
11. Body Composition Characteristics of Female Subjects Classified as Injured or Uninjured ...... 47
12. Aerobic Capacity Characteristics of Female Subjects Classified as Injured or Uninjured...... 49
13. Muscular Strength Characteristics of Male Athletes Classified as Injured or Uninjured ...... 51
14. Muscular Strength Characteristics of Female Athletes Classified as Injured or Uninjured ..••••. 52
15. Results of the Correlation of Physical and Physiological Variables with Injury Frequency (INJFREQ) .... 54
vii TABLE Page
16. Results of the Correlation of Body Composition Variables with Total Injuries (TINJ) and Lower Injuries (LINJ) ...... 57
17. Results of the Correlation of Aerobic Capacity Variables with Total Injuries (TINJ) and Lower Injuries (LINJ) ...... 58
18. Results of the Correlation of Muscular Strength Variables with Lower injuries (LINJ) ...••• 59
19. Results of the Correlation of Body Composition and Aerobic Capacity Variables with Total injuries (TINJ) and Lower Injuries (LINJ) ...... 62
20. Results of the Correlation of Body Composition and Muscular Strength Variables with Lower Injuries (LINJ)...... 63
21. Results of the Correlation of Aerobic Capacity and Muscular strength Variables with Lower Injuries (LINJ) ...... 64
22. Ranked Total Injury Rate (TINJRATE) by Team as Cited in the Literature ...... 66
viii CHAPTER I
INTRODUCTION
Many young people derive significant rewards from participating in organized athletic programs. An athletic program provides its participants with a unique opportunity to mature and to grow both mentally and physically. It develops in them several intangible characteristics such as discipline, cooperation, motivation, responsi bility, stamina and courage. It may prepare them for life in a manner which no other experience equally prepares them. Athletics also results in more tangible changes in its participants including an improvement in aerobic endurance, muscular strength and body composi tion. All of these benefits, however, are not achieved without risk.
Participation in athletics also demands increases in physical activity and subjection of the athletes to situations that are potentially dangerous. For this reason, it is extremely important not only to consider the benefits of athletics, but to concentrate on how these benefits can be achieved at the least possible risk to the participants.
One of the most remarkable characteristics of the human body is its ability to adapt to external stimuli. When a person is exposed for prolonged periods of time to heat or cold or altitude, the body becomes better able to function under these conditions by altering its physical characteristics or modifying its existing physiological
1 mechanisms. Similar changes occur when the body is exposed to another
stimulus, the stress of habitual physical activity. Most coaches and physical educators agree that to excel in athletics, athletes must
endure intense sessions of physical activity in preparation for a
competitive season. The physiological effects of exercise, as cited
by Fox and Mathews (18), are evident in virtually every system of the
body. The efficiency of the cardiorespiratory system improves with
training due to central changes in the heart and lungs allowing
greater cardiac output, greater pulmonary ventilation and greater
diffusion capacity in the lung, as well as peripheral changes including
increased myoglobin content and increased oxidation of carbohydrate
and fat in skeletal muscle. Strength training provides a stimulus
for several changes in the musculoskeletal system including an
increase in the number and size of myofibrils, an increase in the
total amount of protein, an increase in capillary density and an
increase in the strength of bone and connective, tendinous and liga
mentous tissue. Changes are also observed in the body composition
of subjects as a result of physical conditioning. These changes may vary depending on the mode and intensity of the exercise but in
general include a small decrease in body weight brought on by the
combination of a decrease in total body fat and no change or a slight
increase in lean body weight.
It should be the responsibility of every coach to precede a
competitive season with a progressive program of physical conditioning.
Providing the program is designed to include aerobic conditioning and
strength training, all of the previously mentioned benefits of exercise 3
could be achieved. These physiological effects of physical training will benefit the athlete in two ways. First, studies have shown that
athletic performance in athletes of equal ability improves with
increasing muscular strength and aerobic endurance (48,58,64). Second,
and more important with regard to this investigation, studies have
suggested that some athletic injuries are related to various physical
characteristics which may be evaluated in the laboratory. Though
specific research in this area is limited, some of the relationships
suggested include the relationship of low aerobic endurance to increased
incidence of injury (22); the relationship of strength imbalances in
certain leg muscles to muscle strains (8); the relationship of high percent body fat to increased incidence of running injuries (59); and the relationship of greater percent body fat and limited leg strength to increased incidence of lower limb injuries (40). All of these
characteristics can be avoided or minimized by proper screening and
conditioning of the athlete before the start of the season.
It cannot be overemphasized how important it is that the preseason
conditioning program be progressive in nature. It is inexcusable for
a program designed for the purpose of reducing athletic injuries to
be the cause of some injuries. It has been shown that the predominance
of injuries occur in the beginning of a physical activity program, when the participants are in their worst physical condition (19,23,45).
The program, therefore, must be instituted far enough in advance of
the competitive season, and with the appropriate intensity, to allow
adequate, progressive conditioning of the athletes to occur. 4
Statement of the Problem
Most coaches, athletic trainers, team physicians and physical educators agree that the level of physical conditioning of an athlete influences the occurrence of athletic injuries. It should be recog nized that adequate physical conditioning of athletes be accomplished before they are subjected to conditions which precipitate athletic injuries. For this reason, an organized program of progressive physical conditioning must precede any practice sessions that will include drills involving collisions, drills of highly coordinated movements, exercise of high intensity or exercise to exhaustion.
Among the goals of this program are the improvement of body composi tion, aerobic endurance and muscular strength of the participating athletes. A failure to meet these goals may leave an athlete with an excess of body fat, below average ability to maintain heavy muscular exercise, imbalances in muscular strength, a lack of ligamentous or tendinous strength or poor neuromuscular coordination. Each of these characteristics has been implicated in the literature as a contributing factor in a high percentage of athletic injuries. Some administrators of athletic programs, however, still choose to supersede preseason conditioning because of time restrictions imposed by league officials, overemphasis on early skill training, or because of the failure to recognize its absolute need in injury prevention. 5
Purpose of the Study
The influence of physical conditioning on the occurrence of athletic injuries has been suggested for years. Often such suggestions are only anecdotal in nature however, and are not substantiated by scientific or statistical evidence. Several physical and physiological variables that may relate to injury were investigated in this study including body composition, aerobic capacity and muscular strength.
If substantial evidence could be demonstrated that such variables do indeed influence injury occurrence, then more coaches and administrators might be convinced to sufficiently evaluate and condition their athletes prior to the competitive season. The purpose of this study, therefore, was to more fully investigate the influence of several physical and physiological variables on the incidence of injury in an athletic population.
Delimitations of the Study
1. The population for this study consisted of male and female varsity athletes present at The Ohio State University during the
1981-1982 school year.
2. Body composition was evaluated by a hydrostatic-technique using estimated residual lung volumes.
#*■ 3. Aerobic capacity was measured by a graded exercise test to voluntary exhaustion on a motor-driven,treadmill using an Erich Jaeger metabolic measurement system (Jaeger Corporation, Rockford, Illinois). 6
4. Muscular strength was measured isokinetically through the
use of the CYBEX II isokinetic dynamometer {CYBEX Division, Lumex
Incorporated, Ronkonkoma, New York).
5. An athletic injury was defined as any sport-related episode
that required the loss of one full day of practice or one entire
athletic conpetition.
Limitations of the Study
1. The physical data were collected by several workers trained and supervised by this investigator.
2. The injury data were collected by several individual student trainers supervised by team physicians and head athletic trainers.
3. Responses by athletes to the different types of tests may have varied due to experience, motivation, attentiveness, verbal encouragement or anxiety.
4. Testing varied as to the time elapsed between the date of the testing and the conclusion of that particular sport's competitive season.
5. No attempt was made to measure residual lung volumes at the time of the hydrostatic evaluation of body density. Instead, residual lung volumes were estimated by measuring vital capacities of the subjects in the same posture as during the hydrostatic evaluation.
6. Aerobic capacity was measured only through the use of a motor-driven treadmill, which in some cases may not be specific to the mode of exercise involved in the sport. 7
7. Measurement of muscular strength was limited to muscle groups used in extension and flexion of the knee joint and was evaluated only by torques nonspecific to joint angle. CHAPTER II
REVIEW OF LITERATURE
The benefits of athletics are derived at the risk and possible
consequence of injury. Physical injury can result in poor athletic performance due to physical limitations and the loss of practice or performance time. Other consequences may also be associated with
injury including the fear of reinjury, a lack of motivation, a loss of self-worth, or even depression. Often the effects of these con sequences are not limited to the individual sustaining the injury, but are also experienced to some degree by the entire team. It is very important therefore, to investigate the significance of several factors which may assist in the prevention of athletic injuries.
Obviously there are numerous variables to consider, some of which are controllable, and others over which no control can be exerted. This study was designed to investigate the relationship of several physical and physiological variables to the incidence of injury in athletics.
It was initiated based on a review of the literature that revealed several important points including; the influence of physical activity on body composition, aerobic capacity and muscular strength; the influence of body composition, aerobic capacity and muscular strength on the incidence of injury; and the influence of modifying various physical characteristics on the prevention of athletic injury.
8 9
The Influence of Physical Activity on Certain Physical and Physiological Variables
The variables under investigation in this study are all relatively dynamic in nature. They can be influenced from month to month, or even week to week by alterations in physical activity or dietary intake.
The fact that they can be manipulated makes them of particular interest with regard to injury prevention.
Body composition. The influence of physical activity on body composition has been investigated in various populations employing several types of exercise programs. It has been demonstrated, perhaps somewhat surprisingly, that changes in body composition associated with physical training are very similar regardless of whether the training used is anaerobic (strength training), aerobic (jogging), or a combi nation of both. Several recent studies suggest that strength training results in a significant increase in lean body weight, a reduction of body fat, and very little change in the total body weight of the subjects (6,46,70). This has proven to be the case in both males and females. Aerobic exercise programs, specifically jogging programs, have produced results very similar to those just described (5,50,72).
It does appear though that the initial level of body fat influences the magnitude of the changes observed. When obese subjects were compared with normal subjects, the obese population showed signifi cantly greater increases in lean body weight and greater reductions in body fat than the lean group, with neither group showing a signifi cant change in total body weight (5,50). This might suggest that body composition in athletes, basically a lean population, may not be 10 influenced by physical training. Wilmore and associates (72) however, have demonstrated changes in body composition, including reduction in body fat and increases in lean body weight, can be elicited through jogging.and strength training programs in lean college students.
Furthermore, several studies have investigated the effects of a competi tive season on body composition in athletes. Normally a competitive season in any sport will include periods of both anaerobic and aerobic training. The results have shown that males and females respond in the same manner, with changes in body composition as previously described including a significant increase in lean body weight, a significant reduction in body fat, and very little change in total body weight
(6,42,65).
Aerobic capacity. Aerobic capacity is determined primarily through the interaction of two components, the ability of the heart to maintain adequate blood flow and the ability of the working musculature to extract oxygen from the circulating blood. Physical activity influences both of these components by inducing central changes in the heart and lungs and peripheral changes in the musculature. One of the most significant central changes following training is the increased pumping ability of the heart. It has been shown that training, especially aerobic training, results in increased ventricular cavity size (52) and increased myocardial activity (47). Through the combination of these two variables, the athlete during maximal exercise displays a cardiac output almost double that of the untrained individual (15).
Since the maximal heart rate is not influenced by training, the conclusion has been that increased cardiac output is based entirely 11 on improved stroke volume (14). Furthermore, increased cardiac output alone may account for anywhere from fifty percent to nearly one hundred percent of the improvement in aerobic performance (12).
Central changes in the lung appear with training also, but are usually not considered as limitations to maximal aerobic capacity. These changes include greater pulmonary ventilation (18) and improved diffusion
capacity of the lung membrane (30), These changes have been attributed to increased efficiency of the respiratory musculature, an opening up of dormant alveoli and pulmonary capillaries, and improved gas ex change in the lung as a result of increased surface area due to the dilation of pulmonary capillaries and stretching of the alveolar membranes (30). The other component of aerobic capacity, the ability of the musculature to extract oxygen from the circulating blood, improves with training as well. The ability of skeletal muscle to oxidize carbohydrate improves significantly with training through an increase in the size and number of mitochondria present in skeletal muscle and an increase in the amount and activity of various oxidative enzymes (36,37). Fat oxidation also improves due mainly to a similar increase in the activity of enzymes responsible for fat metabolism
(26,49). The increased storage in skeletal muscle of myoglobin (57), glycogen (27), and triglyceride (38) as a result of physical activity also improves aerobic capacity.
Muscular strength. Physical activity can also influence muscular strength. The search for the ideal strength training protocol has gone on for decades. The literature contains numerous suggestions by investigators as to which procedure or which device best improves muscular strength. Ultimately however, improvement in muscular
strength does not depend on the procedure or training device used,
hut depends on adaptations in the musculoskeletal system to any pro
gressive and consistent overload. Often the most noticeable adaptation
to strength training is the enlargement of the involved musculature.
This enlargement has been attributed primarily to hypertrophy of
existing muscle fibers (4,18). Each muscle fiber consists of con
stituent structures known as myofibrils. It is actually the increase
in the size and number of these structures, due to an increase in the
amount of contractile protein, that causes the enlargement of the
muscle fibers (29,43), Recently the significance of hyperplasia, or
the appearance of new muscle fibers as a result of longitudinal
splitting, has been investigated as to its contribution in muscular
enlargement and strength gain (28,35), An accurate resolution of the
question concerning hypertrophy versus hyperplasia of muscle fibers will only be possible with further research. Another structural adaptation in muscle to strength training is the increase in capillary
density (2,33). This adaptation may account more for the increase
in muscular endurance following weight training than the increase in
muscular strength. There are several biochemical changes in skeletal
muscle with training including an increase in muscle energy reserves
(44), a small increase in the activity of glycolytic enzymes (13,66), and a small increase in the activity of aerobic enzymes (13), These adaptations, however, are not considered as important to increased
strength due to their somewhat inconsistent reaction to training (18),
Two other types of tissue intimately involved with skeletal muscle in 13 the production of force also show adaptations to strength training.
The stress of muscular activity on bones results in an increase in
the strength of the bone due primarily to a rearrangement of its
cancellous plates (61). Connective tissue also adapts to physical
activity as has been shown by Tipton and co-workers (67). In their
study of the effect of physical activity on the strength of ligament
junctions, they report that the mechanical stress of chronic exercise
is very influential in increasing the strength of ligaments and tendons.
The Influence of Certain Physical and Physiological Variables on the Incidence of Athletic Injury
There has been a tremendous increase in this country over the
last decade in the number of people participating in recreational
exercise programs and organized athletics. Along with the increase
in the number of participants has been a similar increase in the
number of injuries as a result of the activity. An interesting trend
has been identified by several investigators in the occurrence of
injury in recreational programs. It appears that the majority of
injuries appear very early in the programs. Glick and Katch (23),
in a study of middle-aged joggers, reported that 92 out of 105 injuries
experienced by novice joggers occurred in the first four weeks of an
eleven week program. This included 79 percent of all joint sprains,
94 percent of all muscle strains, and 100 percent of all tendon
injuries. In a similar study, injuries were followed over a six month physical conditioning program. Nearly two-thirds of all injuries
occurred within the first six weeks of a twelve week program (19), 14
These results suggest that when previously inactive subjects, possessing high body fat, low endurance and modest strength, begin an exercise program they are much more susceptible to physical injury. As their bodies adapt over a period of weeks, however, the frequency of injury greatly diminishes. Only one study was found that contradicted this trend. Anderson {3), in a report on the fitness program of the United
States Military Academy, indicated that the injury rate in female parti cipants steadily rose as the program continued through the summer.
Most of the literature reviewed on injuries in athletic programs did not investigate or report on this trend. But Klafs and Arnheim (39) cite the Committee on Sports Injuries and Safety of the National
Collegiate Athletic Association as describing "the first three or four weeks of the season .... (as) the most dangerous period in any sport."
This they esqplain is true principally because the athlete is usually lacking in flexibility, often overweight, and generally out of good physical condition when he reports for initial practice. While there is considerable literature describing the injury rates of recreational and athletic programs, very few studies attempt to relate injuries to specific characteristics of the injured participants.
Body composition. The literature regarding the influence of body composition on the incidence of injury appears to be very limited.
Pollock and associates (59) investigated the effect of body weight and percent body fat on incidence of injury in a young group of male joggers.
Although body weight did not show a significant effect, it was found that those subjects sustaining injuries during the program had an average body fat of 18.3 percent, as compared to those subjects free of injury with a significantly lower average body fat of 12.2 percent. Given that the injured group had a mean body weight of 77.5 kilograms and the uninjured group a mean body weight of 74,3 kilograms, this means the injured group was carrying an additional 5 kilograms of adipose tissue throughout the training program. Kowal (40) looked at the effect of body composition on the incidence of injury from an endurance training program in female military recruits. He evaluated body weight and percent body fat by means of a skinfold estimation on 400 women recruits before they began an eight week basic training cycle.
Following the training he classified each participant as having been injured or uninjured as a result of the training. The two groups demonstrated no difference in body weight, but the uninjured group was significantly leaner based on the estimated value of percent body fat. The injured group was further characterized as having sustained injury of major consequence, minor consequence or as a result of overuse.
Although not significantly different, the body fat was highest in the major injury group, lower in the minor injury group, and lowest in the overuse injury group. Kowal felt that, as previously discussed, a factor in the development of injuries was due to the rapid onset of training which did not allow for a progressive exposure to stress and the development of tolerance. Given a chance to gradually reduce excess body fat, subjects may reduce their chance of being injured.
Aerobic capacity. The influence of aerobic capacity on injury incidence has been frequently suggested but seldom proven. The assessment of cardiovascular fitness in professional football and basketball players has shown both groups to be surprisingly out of 16
shape. A study of professional football players reported low aerobic
capacity and the incidence of injury, the study implied that this
relationship did exist. The suggestion of the relationship was based
on statistics cited that revealed a predominance of football injuries
occurred during the second and fourth quarters of football games.
The conclusion was that toward the end of each half of play cardio vascular endurance had a significant influence on the efficiency of
the player's performance, and that the fatigued player was at an
increased risk of serious injury because of it. This same conclusion was reached in another study of professional football players by
Wilmore and associates (71). Parr and co-workers{56) found oxygen uptake in professional basketball players did not differ considerably
from the values reported on professional football players. They too suggested that conditioning players to a greater degree of cardio vascular endurance should be encouraged to forestall fatigue. They
felt that low aerobic capacity led to premature fatigue and disruption of neuromuscularly dependent skill patterns. This meant that more injuries would appear under fatigue conditions than under nonfatigue conditions. The only studies that have attempted to show a relation ship between aerobic capacity and incidence of injury are the studies by Kowal (40) and Pollock and co-workers (59) previously cited. Their results however, do not statistically support the theory that low aerobic capacity leads to injury. Pollock and co-workers(59) found that maximal oxygen consumption was lower in the injured group (43,4 ml./kg.-min.) than the uninjured group (45.2 ml./kg.-min.), but that the difference was not statistically significant. Kowal (40) found 17 that those women who had sustained injuries as a result of basic train ing actually had a higher mean oxygen consumption (37.9 ml./kg.-min,) than those women who had not sustained injuries (36,2 ml./kg.-min.).
One study by Gendel (21) did present evidence that increasing maximal oxygen consumption through exercise reduced complaints in women joggers of fatigue, colds, allergies and even digestive ills. But no mention was made of the influence of aerobic capacity on the number of injuries sustained during the program.
Muscular strength. The influence of muscular strength on incidence of injury has received more attention in the literature. The most common site of athletic injury is the knee, consequently most studies deal with strength measurements of the lower limb and associated lower limb injuries. Many investigators feel that the muscles crossing the knee joint act as very important stabilizers of that joint (55,62),
Studies have demonstrated that conscious contraction of the quadriceps and hamstrings can significantly affect the stability of the knee joint.
Goldfuss and co-workers (25) showed that strong contraction of the quadriceps and hamstrings significantly reduced the amount of abduction and adduction of the knee compared with the deviations found under relaxed conditions. White and Raphael (68) demonstrated that valgus stress to the medial collateral ligament was significantly reduced when the quadriceps were simultaneously loaded. And Pope and associ ates (60) found that the stiffness of the medial musculotendinous complex of the knee could be increased 164 percent by contraction of the quadriceps femoris group, and 208 percent by contraction of the muscle group attached at the pes anserinus. The implication of each study is that by improving the strength of the musculature surrounding
a joint, the joint can be made more stable and less susceptible to
injury, it must be recognized however, that voluntary contractions
of even the strongest muscle group may be too slow to guard against
all knee injuries (60). The incidence of muscle strains has also been
related to strength parameters. Klafs and Arnheim (39) are of the
opinion that muscle strains are more likely in athletes displaying
fatigue, poor posture, uneven muscle strength, inflexibility or poor
form in performance. In a study of collegiate track and football
players, Burkett (8) reported that a strength imbalance of more than
ten percent between the knee flexors resulted in a significant number
of hamstring strains. Of the 37 football players studied, six had a
strength difference of ten percent or more between the knee flexors,
and four of the six sustained injuries to the hamstrings within three weeks of the measurement. At no time were the athletes made aware
of the fact that they were at any higher risk of injury, Nicholas
and co-workers {54) have also suggested that patients with quadriceps weakness have an increased possibility of lower body injury, it appears that other closely related characteristics such as flexibility and ligament strength also influence injury occurrence. Two studies have related flexibility to injury. In one, joint looseness was associated with increased ligament rupture (53), and both showed that inflexibility was highly related with muscle strain (41,53). And the high incidence of medial collateral knee ligament injuries in sports may be partly explained by the findings of Tipton and associates (67) that of all the ligament junctions, the medial collateral was the weakest. 19
The Influence of Modifying Certain Physical and Physiological Variables on the Prevention of Athletic Injury
The results of a recent study on injuries in collegiate football suggest that if an athlete participated for four years, his chance of sustaining a mild injury, one resulting in the loss of less than one week of practice, was 99,1 percent (10), If that same athlete partici pated for only one year his chance of sustaining an injury was still almost 50 percent. Another study by Clarke and Buckley (11) cites injury data from the National Athlete Injury/Illness reporting System.
The data reveal the average annual relative frequency of significant injuries in various collegiate sports. It was found that significant injuries on the average occurred in 36 percent of male wrestlers, 28 percent of female gymnasts, 27 percent of male ice hockey players,
25 percent of male football players, 20 percent of male and female basketball players, and as many as 11 percent of female volleyball players. It is obvious from these data that more might possibly be done in the way of preseason conditioning to better physically prepare an athlete for the rigors of a competitive season.
This topic is addressed by Klafs and Arnheim in their popular text on athletic training (39). They state that four to six weeks of preseason conditioning afford the best insurance against suscepti bility to injury and permit the athlete to enter competition in a good state of physical fitness, provided a carefully graded program is established and adhered to conscientiously. A total body conditioning program has been investigated for its effect on the incidence and severity of knee injuries in high school .football players by Cahill and Griffith (9). The program consisted of exercises to promote
cardiovascular fitness and heat acclimatization, weight training,
flexibility exercises and agility drills. The conclusion after eight
years of observation was that the number and severity of knee injuries
in football can be significantly reduced by total body preseason
conditioning. An update of this study recently appeared which demon
strated continued success of the program {51). The influence of the
program on knee injuries is evident from some of the results of that
update, shown in Table 1.
TABLE 1
THE INFLUENCE OF A PRESEASON CONDITIONING PROGRAM ON THE NUMBER AND SEVERITY OF KNEE INJURIES FROM 1969-1980.
Number of Number of Number of Injuries/ Surgical Period Injuries Participants 1000 players Procedures
1969-1972 85 1254 6.78 19
1973-1976 50 1227 4.08 7
1977-1980 51 1308 3.90 3
[Data from Cahill and Griffith, 1978 (9), and Moore, 1982 (51).]
The study unfortunately presented no evidence that the conditioning program resulted in the measureable improvement of any physical charac teristics. It must still be assumed though that the reduction of injuries was a result of improved overall body conditioning. A similar
study done at the United States Military Academy reported that a 21 preseason conditioning program reduced football injuries among cadets who .had been identified as having preexisting lower extremity injuries
(1). Abbott, the chief investigator in the study, has been cited elsewhere as concluding that not only lower extremity muscle strength led to preventing injuries, but that the influence of overall body conditioning was also extremely important (31). More and more profes sional sports teams are realizing the importance of conditioning for the prevention of injuries. Many of Bill Walton's injury problems in his first year of professional basketball have been attributed to a lack of conditioning. It was reported that in his next two seasons, with adequate preseason conditioning, the results were far fewer injuries (17). And as the result of an injury to Mark Fidrych, a pitcher for the Detroit Tigers baseball team, the training staff of the Tigers has started a six-week total conditioning program for all their pitchers during spring training in an attempt to avoid any future injuries (17). An interesting study done by Eriksson (16) has even led to the country of Sweden initiating a program of ski injury prevention. Eriksson learned from personal communication with skiers that many accidents occurred as a result of the skiers experiencing extreme fatigue just before they fell. Most skiers felt the fall could not be avoided due to the muscular fatigue. He consequently took muscle biopsies before and after a day of downhill skiing and found up to 75 percent of the glycogen normally stored in skeletal muscle had been depleted. His conclusion was that some of the injuries could be prevented by advocating running, cycling or cross-country skiing as a means of physically preparing the skiers for the demanding season of skiing. CHAPTER III
RESEARCH DESIGN AND PROCEDURES
For the purpose of investigating the influence of body composition, aerobic capacity and muscular strength on the incidence of injury in athletics, the following research design and evaluative laboratory procedures were employed.
Research Design
The study was designed to investigate the relationship between certain physical and physiological variables and the incidence of injury in athletics. It involves a multiple regression analysis correlating these previously mentioned variables to the relative frequency and probability of athletic injury.
Selection of subjects. During the summer preceding the 1981-1982 school year, a letter was sent by this investigator to each varsity coach at The Ohio State University. The letter informed them that several physical variables that may relate to athletic performance and injury in their athletes could be evaluated in the laboratory.
It was left to the decision of each coach if such testing would be beneficial to the goals of their program. The selection of subjects, therefore, was influenced by the decision of each coach.
The subjects in this study were varsity athletes at The Ohio
22 23
State University. Each athlete prior to the beginning of the study was given a conplete physical examination by a physician and was informed as to the nature of the investigation. Subjects included male and female members of several varsity sports. Male sports represented include basketball, football, ice hockey, indoor track and wrestling. Female sports represented include basketball, cross country, field hockey, gymnastics, indoor track and volleyball.
Initial exclusion of any subjects was based on (a) the decision of a coach not to have a team participate, (b) the conclusion of the competitive season of a team being past the deadline set by this study, or (c) the observance at the time of testing of any physical limita tions in a specific athlete. Subsequent exclusion of any subjects was due to their inability to complete the conpetitive season, for reasons other than injury, thereby having an unequal probability of sustaining an athletic injury. Table 2 presents the physical descrip tion of the subjects by team.
Physical and physiological variables evaluated. Table 3 presents the physical and physiological variables evaluated in this study with reference to body composition, aerobic capacity and muscular strength.
Evaluating incidence of injury. An injury was defined in this study as any sport-related episode that required the loss of one full day of practice or one entire athletic competition. A "total injury" was any injury of any type that occurred regardless of anatomical location. A "lower injury" was an injury of any type that occurred to the lower limb. A "relative injury frequency" was determined for both total and lower injuries for each subject. This relative injury TABLE 2
PHYSICAL CHARACTERISTICS OF SUBJECTS BY TEAM
MALES AGE (YR.) HEIGHT (CM.) BODY WEIGHT (KG.)
IDNUM TEAM n MEAN (S.D.) MEAN (S.D.) MEAN (S.D,}
102 Basketball 11 19.72 (1.19) 194,65 (12.56) 89,51 (10.28)
107 Football 18 18.33 (0.84) 188.80 ( 5.37) 99.31 (15.28)
110 Ice Hockey 22 20,68 (1.39) 180.45 ( 4.46) 78,94 ( 6.51)
117 Track 11 19,90 (1.13) 175.83 ( 8.13) 72,88 ( 8.48)
119 Wrestling 29 19.44 (1.08) 175,34 ( 7.95) 76.13 (12.32)
FEMALES AGE (YR.) HEIGHT (CM.) BODY WEIGHT (KG.)
IDNUM TEAM n MEAN (S.D.) MEAN (S.D.) MEAN (S.D.)
202 Basketball 13 19.69 (1.60) 177.01 ( 6.94) 64.21 ( 5.21)
203 Cross Country 12 19.33 (1.15) 167.00 ( 3.77) 52.04 ( 5.21}
206 Field Hockey 22 19.31 (1.17) 166.48 ( 6.13) 59.15 ( 8.56)
209 Gymnastics 9 19,11 (1.05) 163.54 ( 4.74) 58.36 ( 4.43)
217 Track 14 19.50 (1.34) 168.81 ( 4.91) 60.08 ( 8.41)
218 Volleyball 10 19,10 (1.10) 175,00 ( 7.61) 66.83 (10.18) 25
TABLE 3
PHYSICAL AND PHYSIOLOGICAL VARIABLES EVALUATED IN THIS STUDY
BODY COMPOSITION VARIABLES
VARIABLE UNIT
AGE (AGE) YR. HEIGHT (HT) CM. BODY WEIGHT (BODYWT) KG. PERCENT BODY FAT (PERFAT) % FAT WEIGHT (FATWT) KG. LEAN WEIGHT (LEANWT) KG.
AEROBIC CAPACITY VARIABLES
VARIABLE UNIT
VENTILATION (VENTLN) L./MIN. MAXIMAL OXYGEN CONSUMPTION (V02LIT) L./MIN. MAXIMAL OXYGEN CONSUMPTION / BODYWT (V02MLKG) ML./KG.-MIN. MAXIMAL HEART RATE (HR) B. /MIN,
MUSCULAR STRENGTH VARIABLES
VARIABLE UNIT
TOTAL EXTENSION TORQUE (KE*SUM) N.M. TOTAL EXTN TORQUE / BODYWT (KE*KG) N.M./KG. TOTAL FLEXION TORQUE (KF*SUM) N.M. TOTAL FLXN TORQUE / BODYWT (KF*KG) N.M./KG. EXTENSION DIFFERENCE (KE*DIF) % FLEXION DIFFERENCE (KF*DIF) % FLEXION/EXTENSION RATIO (K*RATIO) %
(NOTEs * Denotes various speeds of exercise.) 26
frequency (INJFREQ) was calculated by dividing the number of injuries to an individual athlete by the number of injuries to his/her entire team, as seen in Equation 1 and Equation 2. Total injury frequency
(TINJFREQ) and lower injury frequency (LINJFREQ) were both used as dependent variables in a multiple regression model.
Total relative „ m ^ A ^ . . # Total injuries to athlete „ , injury frequency = — — -:--- -— ------X 100 Eqn. 1 J j # Total injuries to team ^ (TINJFREQ)
Lower relative . . „ # Lower miuries to athlete „ „ injury‘jury frequencyfrequ = ~ r - ~ r ; ----- — -- :--- — ------X 100 Eqn, 2 J J ^ J # Lower injuries to team n (LINJFREQ)
Due to the possible skewness of these calculated relative injury frequencies two other dependent variables were created that could hold only a value of zero or one. If an athlete sustained a total injury* total injury (TINJ) was set to one, otherwise it was zero.
If an athlete sustained a lower injury, lower injury (LINJ) was set to one, otherwise it was zero. These dependent variables were used in a second multiple regression model.
Statement of experimental hypotheses. It has been frequently hypothesized that several physical and physiological variables may influence the incidence of athletic injuries. The design of this study allows the investigation of the influence of these variables on the incidence of injury by testing the following experimental hypotheses! 27
1. There is a relationship between body composition variables and total or lower athletic injuries.
2. There is a relationship between aerobic capacity variables and total or lower athletic injuries.
3. There is a relationship between muscular strength variables and lower athletic injuries.
4. There is a relationship between various physical and physio logical variables and total or lower athletic injuries.
Statistical analysis. Standard descriptive statistics were used to describe the physical characteristics of the subjects. Standard descriptive statistics and the TTEST PROCEDURE of the Statistical
Analysis System (32) were used to test the hypothesis that the means of various physical and physiological variables were different for the "uninjured" athletes versus the "injured" athletes. The GLM
PROCEDURE of the Statistical Analysis System (32) was used to test the previously stated experimental hypotheses by using a multiple regression model. The GLM PROCEDURE provides output detailing the analysis of variance table, the partial sum of squares for each independent variable, and beta values for the intercept and each independent variable.
Evaluation of Body Composition
The density of any object is expressed as the ratio of its mass to its volume. Given this relationship, the density of the human body can be evaluated if measurements are made of its mass and volume. 28
Body mass in air. The body weight of each subject was measured to the nearest one-quarter pound using a medical platform scale
(Continental Scale Corporation, Chicago, Illinois). Body weight was then converted to body mass assuming 2.205 pounds of body weight to be equivalent to 1 kilogram of body mass. Body mass in air was expressed in grams.
Body mass in water. The subject sat in a specially designed chair suspended in a stainless steel tank filled with warm water
(approximately 30 to 33° C.). A weighted scuba belt was used to insure total submersion. One trial consisted of the subject forcefully exhaling as much air from the lungs as possible, pulling the head to the knees to fully submerse the entire body, and remaining as still as possible until a signal was received to return to the surface.
The signal was issued by the technician performing the test when the total mass of the system (which included the combined mass of the subject and the weighted chair) had been determined to the nearest
50 grams using a Chatillon autopsy scale (Chatillon Co., New York,
New York). If fluctuations in the scale due to movement of the subject were encountered, the midpoint of the range of values observed was recorded as the total mass in water. Four or more trials were completed depending on the consistency of the measurements. Net body mass in water was obtained by subtracting the mass of the chair and weighted scuba belt from the total mass in water. The mean of the two highest measures of body mass in water was used. Body mass in water was expressed in grams. 29
Residual lung volume. The vital capacity of each subject was measured to the nearest 50 milliliters using a Collins six-liter
Vitalometer (Warren E. Collins, Inc., Braintree, Massachusetts).
This is with the exception of the male basketball team, whose vital capacities were measured with an Ergo-Pneumotest (Erich Jaeger Inc.,
Rockford, Illinois). The subject was seated in a position similar to that assumed during the underwater determination of body mass.
Airflow through the nose was prevented by noseclips. One trial con sisted of the subject inhaling maximally, placing the mouthpiece of the spirometer into the mouth, sealing the lips around the mouthpiece, and forcefully exhaling all air from the lungs. Verbal encouragement was offered to insure maximal effort. Three to five trials were recorded depending on the consistency of the measurements. The mean of the highest two recordings was used. Residual lung volume was estimated by assuming it to be a constant proportion of the measured vital capacity. The proportions used in this study, based on data from Wilmore (69), were as follows:
>WBTps = 10.24] X IV C ^ ]
Female = 10.20] X
RV : Residual lung volume VC : Vital capacity BTPSs Body temperature and pressure, saturated
Residual lung volume was esq>ressed in milliliters.
Water density. The density of the water during the testing procedure was determined based on water temperature. Water density 30 was expressed in grains per milliliter.
Calculations. Body density was calculated according to the
equation of Goldman and Buskirk (24), as seen in Equation 3.
D0 - Equation 3
”a - *W - R VBTPS ^ ^ °W
D : Body density (g./ml.) B M j Body mass in air (g.) A ; Body mass in water (g.) D s Water density (g,/ml.) w RVBTpss Residual lung volume in BTPS (ml.)
Percent body fat was calculated according to the equation of Brozek,
Grande, Anderson and Keys (7), as seen in Equation 4.
% Fat = (4.57 / D - 4,142] X 100 Equation 4 B
% Fat: Percent body fat D s Body density (g./ml.) B
Fat weight was calculated as seen in Equation 5.
Fat Wt. (kg.) = Body Wt. (kg.) X Percent Fat Equation 5
Lean weight was calculated as seen in Equation 6.
Lean Wt. (kg.) = Body Wt. (kg.) - Fat Wt. (kg.) Equation 6 31
Evaluation of Aerobic Capacity
The determination of maximal oxygen consumption is generally considered the best measure of physical work capacity and the best reflection of the ability to maintain heavy physical exercise. Its determination is accomplished by exercising the subject to exhaustion and analyzing the expired air for oxygen content, carbon dioxide content, and total volume.
Procedure. Maximal oxygen consumption was determined by a graded exercise test to voluntary exhaustion on a motor-driven treadmill.
The protocol used was a minor modification of The Ohio State Method as cited by Fox and Mathews (18). Before the test began, each subject was asked to stretch the legs, was given a brief orientation session on the treadmill, and was informed of the objective of the test. At this point the subject was given a drink of water, noseclips were affixed to the nose and the mouthpiece was inserted into the mouth,
A brief period of walking (3-4 minutes) preceded the test. The first stage of the test consisted of three minutes of running at 2.68 m./sec.
(6 miles/hr.) at 0 % grade. At the end of the first three minutes, the second stage began with the grade of the treadmill increased to
2 % grade and the speed of the treadmill either held constant at
2.68 m./sec,, or increased to 3.13 m./sec. (7 miles/hr.), depending on the anticipated fitness level of the subject. This stage lasted for two minutes. During each subsequent stage, also of two minute duration, the speed of the treadmill was held constant while the grade was increased by 2 %. The protocol is demonstrated in Table 4. 32
TABLE 4
TREADMILL PROTOCOL USED FOR DETERMINATION OF MAXIMAL OXYGEN CONSUMPTION
DURATION SPEED SPEED GRADE STAGE (MINUTES) (M./SEC.) (MILES/HR. ) [PERCENT)
0 3-4 1.34 3 0
1 3 2.68 6 0
2 2 2.68/3.13 6/7 2
3 2 2.68/3.13 6/7 4
4 2 2.68/3,13 6/7 6
5 2 2.68/3.13 6/7 8
6 2 2.68/3.13 6/7 10
7 2 2.68/3.13 6/7 12
[Modified from The Ohio State Method cited by Fox and Mathews (18).]
The measurement of oxygen consumption was accomplished using an
Ergo-Pneumotest metabolic measurement system (Erich Jaeger inc.,
Rockford, Illinois). The system contains a minicomputer which is programmed to collect and analyze data every thirty seconds during the test. The subjects were asked to continue running on the treadmill to the completion of as many of these thirty second periods as possible. When the subject began to show signs of exhaustion (heart rate in excess of 180 beats/minute, a respiratory exchange ratio greater than 1,00, or visual signs of discomfort) verbal encouragement was offered to insure maximal effort. At about 15 to 20 seconds into 33
a thirty second collection period, the subject was asked if they felt
they could complete one more thirty second interval. If a "thumbs up”
response was obtained from the subject the test was continued, if
however, a "thumbs down” response was given the test was terminated
at the conclusion of that thirty second interval. At the conclusion
of the test the treadmill was slowed to 1.34 m./sec. {3 miles/hr.) and
returned to 0 % grade. The subject completed a four to five minute
cool down on the treadmill in an attempt to bring the heart rate back
down below 100 beats/minute.
The Ergo-Pneumotest measures expired volumes through the use of
a pneumotachograph. The subject inhales room air through a special
low resistance "Y-valve”, with all exhaled air being directed into a
1.5 meter flexible tube. When the expired air reaches the pneumo
tachograph, it encounters a fine mesh screen with a defined flow
resistance. A small decrease in pressure develops across the screen which is proportional to the flow speed. This difference in air pressure arising on either side of the flow resistance is converted by a pressure transducer into an electrical signal. This signal is amplified and stored by the computer. It then integrates the flow rate over thirty seconds and calculates the volume expired, expressing it in liters/minute (BTPS). After passing through the pneumotacho graph, the expired air enters a mixing chamber. The mixing chamber is closed to the outside by a diffusion filter, yet allows expired air to escape with little resistance. To determine carbon dioxide content of the expired air, a sample of mixed air is drawn from the mixing chamber, through a calcium chloride humidity absorber, into 34
the carbon dioxide analyzer. The carbon dioxide analyzer is based
on the infrared absorption principle. The percentage of carbon dioxide
is analyzed, stored in the computer, and displayed digitally on the
front of the analyzer. After passing through the carbon dioxide analyzer,
the sanple passes through a sodalime carbon dioxide absorber into the
oxygen analyzer. This analyzer is based on the fuel cell principle.
The difference in oxygen partial pressure between ambient air and the
esqpired air is analyzed. This partial pressure is converted into a
percentage of oxygen, stored in the computer, and displayed digitally
on the front of the analyzer. The procedure used to calibrate the pneumotachograph and analyzers can be found in Appendix A. Heart rate
in most cases was monitored each minute using a Hewlett-Packard 1500B
electrocardiograph (Hewlett-Packard, Waltham, Massachusetts).
Calculations. The volume of expired air was converted to standard
conditions for calculation of oxygen consumption using Equation 7,
Volume^pj^ = Volume^ g X 273°C. X PB ” PH20 Equation 7 273°C. + T 760 mm.Hg, ri
STPD: Standard temperature (273°C.), pressure (760 mm.Hg.), dry ATPSs Ambient temperature, pressure, saturated . . o Ta : Ambient temperature ( C.) P : Barometric pressure (mm.Hg.) s PH2Qs VaPor pressure of water at ambient temperature (mm.Hg.)
The volume of oxygen consumed was calculated using Equation 8, as can be seen on the following page. 35 E02 EC02 = V — V F Equation 8 '02 E 102 E E02 1 — (P + P ) 1 102 IC02
Oxygen consumption (liters/min.) '02 Ventilation (liters/min.) Fraction of inspired oxygen {%) Iconstant] 102 . * Fraction of inspired carbon dioxide (%) [constant] ?IC02* Fraction of expired oxygen {%) ?E02 * Fraction of expired carbon dioxide (%) rEC02S
The collection period which elicited the highest oxygen consump tion in liters/minute was identified. Other variables associated with this collection period were expressed in the study including venti
lation (l./min.), oxygen consumption per kilogram of body weight
(ml./kg.-min.), and heart rate {beats/min,), Oxygen consumption was expressed in milliliters of oxygen consumed per kilogram of body weight by dividing the oxygen consumption in liters/minute by body weight in kilograms.
Heart rate was determined by identifying eleven R-waves and measuring the distance in millimeters from the first R-wave to the eleventh R-wave. This distance was divided into 15,000 (assuming a paper speed of 25 mm./sec.) to calculate heart rate in beats/minute.
In cases where heart rate was not monitored, due to the inability to obtain an adequate trace, maximal heart rate was estimated by palpating the carotid artery immediately following the treadmill test. The pulse was counted for 10 seconds and multiplied by six to obtain a rate in beats/minute. 36
Evaluation of Muscular Strength
Recently a device has been developed that provides "t* objective
measure of maximal muscular force production in humans. This device,
the CYBEX II isokinetic dynamometer, was first described in the
literature by Hislop and Perrine {34). It allows a maximal contrac
tion of the muscle groups being tested by governing the speed of the
contraction. The device evaluates muscular strength by measuring the
torque production of the muscle groups surrounding various joints in
the body.
Procedure. The procedure used for evaluating the torque pro duction of the extensors and flexors of the knee joint is described in Table 5.
Calculations. The peak torques, defined as the highest torques achieved in extension and flexion of the knee joint, were recorded in newton-meters of torque. The peak torque for extension and flexion did not necessarily occur in the same repetition. Peak torque was the only strength variable measured. All other variables associated with muscular strength were calculated based on peak torques.
Maximum torque, expressed in newton-meters, was defined as the greater of the two torques produced by either limb. Minimum torque was defined as the lesser of the two torques produced by either limb.
Total extension torque, expressed in newton-meters, was calculated by adding the maximum and minimum extension torques. Total flexion torque was calculated by adding the maximum and minimum flexion torques.
These sums were also expressed per kilogram of body weight. 37
TABLE 5
PROCEDURE USED FOR THE DETERMINATION OF ISOKINETIC MUSCULAR STRENGTH FOR THE EXTENSORS AND PLEXORS OF THE KNEE JOINT
PREPARATION OF THE RECORDER
1. Calibration: Calibrate the recorder as described in the CYBEX Calibration Instructions found in Appendix B, 2. Danping: Select a damping of 2 on the recorder. 3. Torque scale: Select the torque scale {180 or 360 ft.-lb.) based on predicted torque output. 4. Position scale: Select the 150 degree scale. (Position the stylus on the recorder paper one major division from the baseline with the knee fully flexed. Knee extension should correspond with an upward deflection on the posi tion channel.)
PREPARATION OF THE SUBJECT
(The subject is tested in an upright, seated position with the hips flexed to 90 degrees.)
1. Position the subject in the chair, 2. Secure the lap belt and thigh belt. 3. identify visually and by palpation the center of rotation of the knee joint. 4. Align the input shaft of the dynamometer with the center of rotation of the knee joint. 5. Identify by palpation the malleoli of the ankle. 6. Adjust the lever arm length such that the pad contacts the leg just superior to the malleoli and secure the ankle strap. 7. Verbally instruct the subject to grasp the handles and main tain the body in the upright testing position. 8. Manually support the dynamometer to avoid any extraneous movement.
TESTING OF THE SUBJECT
1. Warm up: Have the subject perform 3 to 5 submaximal repeti tions at each of the speeds to be tested. 2. Starting position: Knee in full flexion (limited by chair). 3. Range of motion: 105-125 degrees. 4. Test: Conduct the testing in the following sequence: a. 60 degrees/second: 3 consecutive maximal repetitions. b. 180 degrees/second: 3 consecutive maximal repetitions. c. 270 degrees/second: 4 consecu+ ~e maximal repetitions. 5. Rest: Allow 20 to 30 seconds rest . tween testing speeds. 6. Chart speed: 5 millimeters/second. 38
Torque extension difference, expressed as a percentage, was calculated by dividing the difference in maximum and minimum extension torques by the maximum extension torque. Torque flexion difference was calculated by dividing the difference in maximum and minimum flexion torques by the maximum flexion torque. These calculations are shown in Equations 9 and 10.
KE*MX - KE*MN KE*DIF = Equation 9 KE*MX
KF*MX - KF*MN KF*DIF = - Equation 10 KF*MX
KE*DIF (KF*DIFJs. Knee extension (flexion) difference (%) KE*MX (KF*MX) s Knee extension (flexion) maximum torque (N.M.) KE*MN (KF*MN) s Knee extension (flexion) minimum torque (N.M.) [Note; * Denotes various speeds of exercise.]
The ratio of flexion torque to extension torque, expressed as a percentage, was calculated by dividing the total flexion torque by the total extension torque, as seen in Equation 11,
K*RATIO = KF*SUM / KE*SUM Equation 11
K*RATIOs Ratio of flexion to extension torque (%) KF*SUM £ Total flexion torque (N.M.) KE*SUM s Total extension torque (N.M.) [Note: * Denotes various speeds of exercise.J CHAPTER IV
RESULTS
The purpose of this investigation was to determine if any relationship exists between measured variables and the incidence of
injury in athletics. To fulfill this purpose, several or all of the previously mentioned physical and physiological variables were measured in 171 varsity athletes representing eleven different teams at The Ohio State University. Each athlete was then followed through the duration of their competitive season and records were kept detailing each injury that occurred.
Incidence of Athletic Injuries
Injury rate. Throughout their competitive seasons, beginning with preseason conditioning and ending with the last competition, the 171 athletes participating in the study sustained 135 "total"
injuries requiring the loss of one full day of practice or one competition. This was a rate of 0.79 total injuries per athlete per
season. This same group sustained 82 "lower" injuries during the
season for a rate of 0.48 lower injuries per athlete per season.
The breakdown by team of total injury rate (TINJRATE) and lower injury rate (LINJRATE), expressed as the number of injuries per athlete, is shown in Table 6 and Table 7.
39 40
TABLE 6
TOTAL INJURY RATE (TINJRATE) RANKED BY TEAM
(TINJRATE) # TOTAL # TOTAL INJURIES TEAM INJURIES # ATHLETES PER ATHLETE
Male Wrestling 40 29 1.38
Female Gymnastics 11 9 1.22
Male Football 19 18 1.06
Female Volleyball 10 10 1.00
Male Track 10 11 0.91
Female Basketball 9 13 0.69
Female Field Hockey 11 22 0.50
Male Ice Hockey 11 22 0.50
Female Track 6 14 0.43
Male Basketball 4 11 0.36
Female Cross Country 4 12 0.33
TOTAL 135 171 0.79 41
TABLE 7
LOWER INJURY RATE (LINRATE) RANKED BY TEAM
(LINJRATE) # LOWER # LOWER INJURIES TEAM INJURIES # ATHLETES PER ATHLETE
Male Track 10 11 0,91
Male Football 14 18 0.78
Male Wrestling 20 29 0.69
Female Gymnastics 6 9 0.67
Female Volleyball 5 10 0.50
Female Basketball 5 13 0.38
Male Basketball 4 11 0.36
Female Track 5 14 0.36
Female Cross Country 4 12 0.33
Male Ice Hockey 5 22 0.23
Female Field Hockey 4 22 0.18
TOTAL 82 171 0.48 42
It can be observed in Table 6 that male wrestling resulted in
the highest rate of total injury (1.38 total injuries per athlete).
Four other teams had total injury rates higher than the rate for
all the athletes combined. The remaining six teams had a total
injury rate well below the combined rate with members of the female
cross country team sustaining the fewest total injuries per athlete.
Male track led all teams in lower injury rate (0.91 lower injuries
per athlete) as seen in Table 7. The five teams highest in total
injury rate proved also to be the highest in lower injury rate, with
all sustaining at least 0.50 lower injuries per athlete.
Injury probability. Injury rates, as just described, do have
merit in discussing the distribution of injuries among teams. They
fail however, to reflect the probability of an individual athlete
sustaining an injury in their sport. For this reason, the incidence
of injuries has also been described in a manner which reflects this
individual probability. An injury probability (INJPROB) was calculated
for each team by dividing the number of athletes who had sustained at
least one injury by the total number of athletes on the team. The
total injury probability (TINJPROB) and lower injury probability
(LINJPROB), expressed as the proportion of injured athletes to total
athletes, were calculated and are shown in Table 8 and Table 9.
The combined results for total injury probability demonstrate a
50 percent chance of an individual athlete sustaining a "total" injury
severe enough to cause the loss of at least one full day of practice
or one competition (Table 8). six athletic teams equaled or exceeded this probability, with the chances of injury for individuals on three 43
TABLE B
TOTAL INJURY PROBABILITY (TINJPROB) RANKED BY TEAM
(TINJPROB) # ATHLETES # ATHLETES WITH WITH TOTAL TOTAL INJURIES TEAM INJURIES # ATHLETES PER ATHLETE
Male Track 8 11 0.73
Male Wrestling 21 29 0.72
Female Volleyball 7 10 0.70
Female Gymnastics 6 9 0.67
Female Basketball 7 13 0.54
Male Football 9 18 0. 50
Female Track 6 14 0.43
Female Field Hockey 9 22 0.41
Male Basketball 4 11 0.36
Male Ice Hockey 7 22 0. 32
Female Cross Country 2 12 0.17
TOTAL 86 171 0.50 44
TABLE 9
LOWER INJURY PROBABILITY (LINJFROB) RANKED BY TEAM
CLINJPROB) # ATHLETES # ATHLETES WITH WITH LOWER LOWER INJURIES TEAM INJURIES # ATHLETES PER ATHLETE
Male Track 8 11 0.73
Female Gymnastics 6 9 0.67
Male Wrestling 13 29 0.45
Male Football 7 18 0.39
Female Basketball 5 13 0.38
Male Basketball 4 11 0.36
Female Track 5 14 0. 36
Female Volleyball 3 10 0.30
Male Ice Hockey 5 22 0.23
Female Field Hockey 4 22 0.18
Female Cross Country 2 12 0.17
TOTAL 62 171 0.36 45
teams {male track, male wrestling, and female volleyball) reaching
over 70 percent. The combined probability of lower injury was
somewhat lower, as seen in Table 9, where 62 out of 171 athletes
(36 percent) sustained lower injuries that affected practice or playing time. Male track and female gymnastics demonstrated probabili
ties of lower injury nearly double that of the probability of the
entire group of athletes.
Comparison of Injured and Uninjured Athletes
It was of interest to express the means and standard deviations of the characteristics of the subjects having classified each partici pant as being "injured" or "uninjured" upon completion of the season.
Simple t-tests were then run on each variable, using the TTEST
PROCEDURE of the Statistical Analysis System (32), to determine if any variable could be identified whose means significantly differed
between the injured and uninjured groups.
Body composition. The description of body composition character
istics of the male subjects is presented in Table 10. Each participant was classified as having sustained at least one total or lower injury during the season, or having completed the season free of injury, in observing the comparison of injured versus uninjured athletes on the basis of total injury, the injured group tended to be slightly older, taller and heavier, with less body fat and more lean weight. In no case however were the means of the two groups significantly different.
With regard to lower injury the injured group again proved to possess TABLE 10
BODY COMPOSITION CHARACTERISTICS OP MALE SUBJECTS CLASSIFIED AS INJURED OR UNINJURED
TOTAL INJURY INJURED UNINJURED
t-TEST VARIABLE MEAN (S.D.) n MEAN (S.D.) n DIFFERENCE
Age (yr.) 19,67 ( 1.28) 49 19.54 ( 1.48) 42 0.43 Height (cm.) 182,05 (10.11) 49 181.15 (10.27) 42 0.42 Body Weight (kg.) 82.27 (14.96) 49 81.86 (14.14) 42 0.46 Percent Eat (%) 10.39 ( 3.55) 38 11.61 ( 3.67) 30 - 1.38 Fat Weight (kg.) 8.35 ( 3.32) 38 9,10 ( 3.80) 30 - 0.87 Lean Weight (kg.) 71.23 (10.25) 38 68,04 ( 8.70} 30 1.36
LOWER INJURY INJURED UNINJURED
t-TEST VARIABLE MEAN (S.D.) n MEAN (S.D.) n DIFFERENCE
Age (yr.) 19.64 ( 1.27) 37 19.59 ( 1.44) 54 0,19 Height (cm.) 183.80 ( 9.97) 37 180,15 (10.08) 54 1.71 Body Weight (kg.) 84.41 (15.39) 37 81.40 (13.91) 54 0.97 Percent Eat (%) 10,34 ( 3.11) 28 11.34 ( 3.94) 40 - 1.12 Fat Weight (kg.) 8.34 { 2.83) 28 8,92 t 3.97) 40 - 0.67 Lean weight (kg.) 72,09 (10.37) 28 68.23 ( 8.92) 40 1.64 TABLE 11
BODY COMPOSITION CHARACTERISTICS OP FEMALE SUBJECTS CLASSIFIED AS INJURED OR UNINJURED
TOTAL INJURY INJURED UNINJURED
t-TEST VARIABLE MEAN (S.D.) n MEAN (S.D.) n DIFFERENCE
Age (yr.) 19.56 ( 1.30) 37 19.16 ( 1.15) 43 1.39 Height (cm.) 170.45 ( 8.26) 37 168.52 ( 6.25) 43 1.19 Body Weight (kg.) 61.91 ( 8.64} 37 58.25 ( 7.78) 43 1.99 * Percent Fat (%) 17,93 ( 4.25} 28 18.37 ( 4.50) 40 - 0.41 Fat Weight (kg.) 10,96 ( 3.30) 28 10.63 ( 3.26) 40 0.41 Lean Weight (kg.) 49.74 { 6.39) 28 46.85 ( 6.01) 40 1.90
LOWER INJURY INJURED UNINJURED
t-TEST VARIABLE MEAN (S.D.) n MEAN (S.D.) n DIFFERENCE
Age (yr.) 19.60 ( 1.32) 25 19.25 ( 1.18) 55 1,16 Height (cm,) 170.68 ( 8.44) 25 168.84 ( 6.67) 55 1.05 Body Weight (kg.) 63.50 { 8.81) 25 58,32 ( 7.66) 55 2.67 * Percent Fat (%) 17,50 ( 4.40) 20 18,47 ( 4.38) 48 - 0.83 Fat Weight (kg.) 10. B9 ( 3.42) 20 10.72 ( 3.22) 48 0.19 Lean Weight (kg.) 50.71 ( 6.00) 20 46,93 ( 6.12) 48 2.34 *
* p < 0.05 *sl 48
more height, body weight and lean weight than the uninjured group,
while having a lower percent body fat and slightly less fat weight.
The female subjects showed a trend remarkably similar to the male
subjects with regard to total and lower injury. Table 11 presents
the body composition characteristics of the female subjects classified
by injury occurrence. Those female athletes sustaining at least one
total injury proved to be older, taller and heavier with a lower
percent body fat and more lean weight than the group with no total
injuries^. The means for body weight between the two groups showed
a significant difference in both the total and lower injury classifi
cations. The other significant difference noted is for lean weight
between the group with lower injuries versus the group free of lower
injuries.
Aerobic capacity. The measurement of variables related to maximal
aerobic capacity was completed only on female subjects. The descrip
tion of these variables is presented in Table 12, In comparing the
uninjured and injured groups with regard to total injury, no signifi
cant differences were found in means. The injured group did however
show a tendency toward higher maximal minute ventilations and maximal
oxygen consumptions on a liter per minute basis. The means for maximal
oxygen consumption did differ significantly in the lower injury groups.
When oxygen consumption was expressed per kilogram of body weight to
eliminate the influence of body size, it was found that the uninjured
group possessed a slightly higher mean consumption with respect to
both total and lower injury.
i TABLE 12
AEROBIC CAPACITY CHARACTERISTICS OP FEMALE SUBJECTS CLASSIFIED AS INJURED OR UNINJURED
TOTAL INJURY INJURED UNINJURED
t-TEST VARIABLE MEAN (S.D.) n MEAN (S.D.) n DIFFERENCE
Ventilation (l./min,) 92.25 ( 7.10) 25 88,82 { 9.77) 16 1.21 V02 Max (1,/min,} 2.94 ( 0.37) 25 2.80 ( 0.34) 16 1.24 V02 Max/Wt, (ml,/kg.-min.) 48.53 ( 8.04) 25 49,69 ( 6.60) 16 - 0.51 Heart Rate Max (b./min.) 191.80 (11.07) 25 192,28 (11.50) 15 - 0,13
LOWER INJURY INJURED UNINJURED
t-TEST VARIABLE MEAN (S.D.) n MEAN (S.D.) n DIFFERENCE
Ventilation (1,/min.) 94.50 ( 6.46) 9 88.94 ( 9.18) 32 1,69 V02 Max (1,/min.) 3.07 ( 0.34) 9 2.79 { 0.34) 32 2,17 * V02 Max/Wt, (ml./kg.-min.) 47.25 ( 7.56) 9 49.80 ( 7.10) 32 - 0.95 Heart Rate Max (b./min.) 188.44 ( 9.68) 9 193.16 (11.53) 31 - 1.12
* p < 0.05 Muscular strength. The muscular strength characteristics of the male subjects are presented in Table 13. The variables included express the strength of the extensors and flexors of the knee joint per kilogram of body weight, the percentage difference between the strength of bilateral extension and flexion, and the ratio of the strength of the flexors to the strength of the extensors. All varia bles are expressed at three different speeds of contraction including
60, 180 and 270 degrees per second. As observed in Table 13, no statistical differences were found in the means between the injured and uninjured groups for any strength variable.
The muscular strength results of the females (Table 14) did show a tendency to separate the injured and uninjured groups. The strength of the extensors of the knee joint, as characterized by the sum of the two peak torques per kilogram of body weight, was consistently higher in the injured group. This difference became more obvious with increasing speed, with the difference at high speed achieving statisti cal significance. Virtually no difference was found in the means of knee flexion strength between the injured and uninjured groups at any speed tested. The ratio of flexion to extension strength did appear to differ between the two groups. The injured group consistently demonstrated a lower ratio, again with the difference becoming more obvious with increasing speed. TABLE 13
MUSCULAR STRENGTH CHARACTERISTICS OP MALE ATHLETES CLASSIFIED AS INJURED OR UNINJURED
LOWER INJURY INJURED UNINJURED
t-TEST VARIABLE MEAN (S.D.) n MEAN (S.D.) n DIFFERENCE
60 DEGREES/SECOND
Extn, Sunt / Wt, (Nm,/kg.) 5,91 (0.87) 34 5,84 (0.85) 54 0,36 Extn, Difference (%) 6.87 (5.43) 34 6.50 (5.25) 54 0.32 Flxn, Sunt / Wt. (Nm./kg.) 3.71 (0.57) 34 3.67 (0.52) 54 0.28 Flxn, Difference (%) 6.06 (5.12) 34 6.13 (6.16) 54 - 0.06 Flxn,/Extn. Ratio (%) 62.95 (6.47) 34 63.51 (8.71) 54 - 0.32
180 DEGREES/SECOND
Extn. Sum / Wt. (Nm./kg.) 4,16 (0.58) 34 4.09 (0.59) 54 0.57 Extn, Difference (%) 7.20 (5.73) 34 5.89 (4.43) 54 1,20 Flxn, Sum / Wt, (Nm./kg.) 2.83 (0.44) 34 2,82 (0.39) 54 0,11 Flxn, Difference (%) 5.62 (5.40) 34 6.32 (5.19) 54 - 0,60 Flxn,/Extn, Ratio (%) 68.10 (7.25) 34 69.41 (8.10) 54 - 0.77
270 DEGREES/SECOND
Extn. Sum / Wt, (Nm./kg,) 2,95 (0.46) 34 2,94 (0.43) 54 0.11 Extn, Difference (%) 5,78 (5.07) 34 5.77 (4.98) 54 0,76 Flxn, Sum / Wt. (Nm./kg.) 2,22 (0.39) 34 2,23 (0.31) 54 - 0.26 Flxn, Difference {%) 6.56 (6.65) 34 6.11 (5.41) 54 0.35 Flxn,/Extn, Ratio (%) 75.40 (9.24) 34 76.52 (7.82) 54 - 0.61 TABLE 14
MUSCULAR STRENGTH CHARACTERISTICS OF FEMALE ATHLETES CLASSIFIED AS INJURED OR UNINJURED
LOWER INJURY INJURED UNINJURED
t-TEST VARIABLE MEAN (S.D.) n MEAN (S.D.) n DIFFERENCE
60 DEGREES/SECOND Extn. Sum / Wt, (Nm./kg.) 4.95 (0.62) 23 4.76 (0.59) 45 1.24 Extn, Difference (%) 7.79 (7.43) 23 7.22 (4.82) 45 0.33 Flxn. Sum / Wt, (Nm./kg.) 3.20 (0.35) 23 3.17 (0.40) 45 0.26 Flxn. Difference (%) 6,48 (5.55) 23 7.21 (6.68) 45 - 0.45 Flxn,/Extn. Ratio (%) 65,27 (8.53) 23 66.98 (6.28) 45 - 0,94
180 DEGREES/SECOND Extn, Sum / Wt, (Nm./kg.) 3.43 (0.38) 23 3.24 (0.40) 45 1.85 Extn, Difference (%) 4.75 (5.50) 23 6.64 (5.92) 45 - 1.27 Flxn. Sum / Wt. (Nm./kg.) 2.39 (0.28) 23 2.40 (0.35) 45 - 0.09 Flxn. Difference (%} 6.61 (5.85) 23 5.95 (4.22) 45 0.53 Flxn./Extn, Ratio (%) 70,33 (9.60) 23 74.16 (7.56) 45 - 1.80
270 DEGREES/SECOND Extn, Sum / Wt, (Nm./kg.) 2,43 (0.32) 23 2,26 (0.33) 45 2.04 * Extn, Difference (%) 5.37 (3.95) 23 6,46 (5.93) 45 - 0.79 Flxn. Sum / Wt, (Nm,/kg.) 1,86 (0.26) 23 1.87 (0.28) 45 - 0,17 Flxn, Difference (%) 7.94 (6,66) 23 6,53 (5.15) 45 0,96 Flxn./Extn, Ratio (%) 77.16 (9.45) 23 83.12 (9.49) 45 - 2.28 *
* p < 0,05 ui ro 53
Correlation of Variables with Injury Frequency
The first model for multiple linear regression employed in this study used total and lower injury frequency as the dependent variables.
Several . different combinations of independent variables were selected in an attempt to establish a significant relationship.
Total injury frequency. The results of the correlation of body composition data and aerobic capacity data with total injury frequency
(TINJFREQ) are shown in Table 15. it was found that no significant relationship existed between the frequency of total injury and either body composition or aerobic capacity variables. These results suggest that the physical characteristics of an athlete do not influence the relative frequency with which "total" athletic injuries occur.
Lower injury frequency. Table 15 also presents the results of the correlation of physical data with lower injury frequency
(LINJFREQ). As was the case with total injury frequency, no signi ficant relationship was found to exist between the frequency of lower injury and body composition, aerobic capacity or muscular strength data. The fact that no significant relationship was established between the physical and physiological data and injury frequency was probably due to the fact that the distributions of both total and lower injury frequency were biased by several factors which could not be controlled for in the study. 54
TABLE 15
RESULTS OF THE CORRELATION OF PHYSICAL AND PHYSIOLOGICAL VARIABLES WITH INJURY FREQUENCY (INJFREQ)
TOTAL INJURY FREQUENCY (TINJFREQ)
2 INDEPENDENT VARIABLES F P r
BODY COMPOSITION 1.53 .1158 .1401 AEROBIC CAPACITY 0.45 .8369 .0742
LOWER INJURY FREQUENCY (LINJFREQ)
2 INDEPENDENT VARIABLES F P r
BODY COMPOSITION 1.55 .1073 .1421 AEROBIC CAPACITY 1.36 .2673 .1312 MUSCULAR STRENGTH 60 DEGREES/SECOND 1.31 .2011 .1233 180 DEGREES/SECOND 1.35 .1823 .1260 270 DEGREES/SECOND 1,51 .1085 .1393 55
Correlation of Variables with Injury Occurrence
The second model for multiple linear regression employed in this study used the dependent variables total injury (TINJ) and lower injury (LINJ). As previously mentioned, these variables can hold only a value of zero or one, making this a probabilistic model.
The results on the following pages first describe the relationship of the variables independently, and later in various combinations.
Body composition. The results presented in Table 16 demonstrate that a relationship does exist between body composition variables and the occurrence of athletic injuries. The dependent variable is total injury (TINJ) or lower injury (LINJ) occurrence. The independent variables in both regressions are team, age, height, body weight, percent body fat and lean weight. Team was included in the model to allow all subjects to be entered regardless of sex, body size or the sport in which they participated. Both relationships demonstrated statistical significance at the 0,05 level. Both models are similar in that they can account for approximately 28 to 29 percent of the variability in total injury (TINJ) and lower injury (LINJ). The partial sum of squares results, included in Appendix D, allow some inference to be made as to which variables are contributing the most to the regression model. They basically partial out the influence of the other variables and examine the relationship of one specific * independent variable to the dependent variable. In some cases, when a p-level for a partial correlation approaching one was found for a variable, that specific variable was eliminated, thereby increasing 56 the strength of the overall relationship. The equation for calculating the probability of a total or lower injury can be formulated using the
beta (B) values reported for each regression model which can be found in Appendix D.
Aerobic capacity. The results concerning the influence of aerobic capacity on injury displayed in Table 17 should be evaluated with some degree of caution due to the small sample size. When team, age, body weight, ventilation and maximal oxygen consumption (in liters per minute) were correlated with total injury (TINJ), a significant relationship (p < 0.05) was found that explained almost 32 percent of the variability in injuries. In the model relating aerobic capacity to lower injuries, the variable team was eliminated from the model due to its partial sum of squares results. The resultant model shown in
Table 17 includes the independent variables age, body weight, venti lation and maximal oxygen consumption. A significant relationship was found in this model with an r-square of 0.2887, indicating the ability to explain almost 29 percent of the variability in lower injuries.
Muscular strength. The variables concerning muscular strength were evaluated individually according to the speed at which they were measured, and were related only to the occurrence of lower injuries.
Similar results were found at each of the three speeds as can be seen in Table 18. The variable height was included in these models to account for the changes in lever arm length that accompany isokinetic strength testing. At 60 degrees/second a relationship was found which was significant at the 0.05 level between the independent variables 57
TABLE 16
RESULTS OF THE CORRELATION OF BODY COMPOSITION VARIABLES WITH TOTAL INJURIES (TINJ) AND LOWER INJURIES (LINJ)
CORRELATION WITH TOTAL INJURIES (TINJ)
ANALYSIS OF VARIANCE RESULTS
2 SOURCE df SS MS F p r
MODEL 13 9.6421 0.7471 3.72 .0001 .2838 ERROR 122 24.3284 0.1992 TOTAL 135 33.9705
MODEL TINJ = INT + Bl(TEAM) + B2(AGE) + B3(HT) + B4(BODYWT) + B5(PERFAT) + B6(LEANWT)
CORRELATION WITH LOWER INJURIES (LINJ)
ANALYSIS OF VARIANCE RESULTS
2 SOURCE df SS MS F P ' r
MODEL 13 9.0002 0.6923 3.83 .0001 .2897 ERROR 122 22.0586 0.1808 TOTAL 135 31.0588
MODEL LINJ = INT + Bl(TEAM) + B2(AGE) + B3(HT) + B4(BODYWT) + B5(PERFAT) + B6(LEANWT) 58
TABLE 17
RESULTS OF THE CORRELATION OF AEROBIC CAPACITY VARIABLES WITH TOTAL INJURIES (TINJ) AND LOWER INJURIES (LINJ)
CORRELATION WITJi TOTAL INJURIES (TINJ)
ANALYSIS OF VARIANCE RESULTS
SOURCE df SS MS F p r2
MODEL 6 3.0976 0.5162 2.64 .0330 .3175 ERROR 34 6.6584 0.1958 TOTAL 40 9.7560
MODEL TINJ = INT + Bl(TEAM) + B2(AGE) + B3(BODYWT) + B4{VENTLN) + B5(V02LIT)
CORRELATION WITH LOWER INJURIES (LINJ)
ANALYSIS OF VARIANCE RESULTS
2 SOURCE df SS MS F P r
MODEL 4 2.0285 0.5071 3.65 .0134 .2887 ERROR 36 4.9958 0.1387 TOTAL 40 7,0243
MODEL LINJ = INT + Bl(AGE) + B2 (BODYWT) + B3(VENTLN) + B4(V02LIT) 59
TABLE 18
RESULTS OP THE CORRELATION OP MUSCULAR STRENGTH VARIABLES WITH LOWER INJURIES (LINJ)
60 DEGREES/SECOND ANALYSIS OP VARIANCE RESULTS
2 SOURCE df SS MS F p r
MODEL 15 6.5626 0.4375 2.07 .0148 .1814 ERROR 140 29.6104 0.2115 TOTAL 155 36.1730
MODEL LINJ = INT + Bl(TEAM) + B2(HT) + B3(KEAKG) + B4(KFAKG) + B5(KEADIF) + B6(KFADIF)
180 DEGREES/SECOND ANALYSIS OF VARIANCE RESULTS
2 SOURCE df SS MS F p r
MODEL 15 6.8300 0.4553 2.17 .0099 .1888 ERROR 140 29.3430 0.2095 TOTAL 155 36.1730
MODEL LINJ = INT + Bl(TEAM) + B2{HT) + B3{KEBKG) + B4(KFBKG) + BS(KEBDIF) + B6(KFBDIF)
270 DEGREES/SECOND ANALYSIS OF VARIANCE RESULTS
2 SOURCE df SS MS F p r
MODEL 15 6.9850 0.4656 2.23 .0078 .1931 ERROR 140 29.1880 0.2084 TOTAL 155 36.1730
MODEL LINJ = INT + Bl(TEAM) + B2(HT) + B3(KECKG) + B4(KFCKG) + B5(KECDIF) + B6(KFCDIF) 60
associated with the team, height, leg strength and bilateral leg
symmetry of the subjects and the dependent variable lower injury
(LINJ). This relationship however, as was true of the relationships
at the other two speeds tested, could account for slightly less
than 20 percent of the variability in the probability of sustaining
a lower injury. The significance of the relationship increased
slightly with increasing speed.
Combination of physical and physiological variables. Table 19
shows the results of the correlation of body composition and aerobic
capacity variables with total and lower injury, in each case the
independent variables included team, age, lean weight, and maximal
oxygen consumption (liters/minute). While independently body compo
sition and aerobic capacity both demonstrated significant relation
ships with injury, no such relationship was seen with a combination of these variables.
The results shown in Table 20 describe the correlation of lower
injury with a combination of body composition and muscular strength variables. This combination proved to be the most significant
combination of variables tested. The first model included the inde pendent variables team, age, height, lean weight, and leg strength variables tested at 60 degrees/second. The relationship was signifi
cant (p < .05) and explained about 30 percent of the variability in lower injury (LINJ). The second model included the variables team, age, height, lean weight, quadriceps strength at all three speeds tested, and the percentage difference between quadriceps at all three speeds tested. This model resulted in the highest r-square of 2 of any model (r — .3845) indicating that almost 40 percent of the variability in lower injury (LINJ) could be explained by the variability in that combination of variables.
And finally, the combination of aerobic capacity and muscular strength variables was investigated, as seen in Table 21. This combination, including team, age, maximal oxygen consumption and quadriceps strength, did not demonstrate a significant relationship with lower injury occurrence. 62
TABLE 19
RESULTS OP THE CORRELATION OF BODY COMPOSITION AND AEROBIC CAPACITY VARIABLES WITH TOTAL INJURIES (TINJ) AND LOWER INJURIES (LINJ)
CORRELATION WITH TOTAL INJURIES (TINJ)
ANALYSIS OF VARIANCE RESULTS
2 SOURCE df SS MS F P r
MODEL 4 0.9045 0.2261 1.10 .3779 .1398 ERROR 27 5.5641 0.2060 TOTAL 31 6.4687
MODEL TINJ = INT + Bl(TEAM) + B2{AGE) + B3(LEANWT) + B4(V02LIT)
CORRELATION WITH LOWER INJURIES (LINJ)
ANALYSIS OF VARIANCE RESULTS
2 SOURCE df SS MS F P r
MODEL 4 0.6514 0.1628 1.23 .3206 .1544 ERROR 27 3.5673 0.1321 TOTAL 31 4.2187
MODEL LINJ = INT + Bl(TEAM) + B2(AGE) + B3(LEANWT) + B4(V02LIT) 63
TABLE 20
RESULTS OF THE CORRELATION OF BODY COMPOSITION AND MUSCULAR STRENGTH VARIABLES WITH LOWER INJURIES (LINJ)
60 DEGREES/SECOND
ANALYSIS OF VARIANCE RESULTS
SOURCE df SS MS F p r2
MODEL 16 8,3120 0,5195 2.78 .0009 .2998 ERROR 104 19.4069 0.1866 TOTAL 120 27.7190
MODEL LINJ = INT + Bl(TEAM) + B2(AGE) + B3(HT) + B4(LEANWT) + B5{KEAKG) + B6{KEADIF) + B7(KFAKG) + B8{KFADIF) + B9(KARATIO)
COMBINATION OF SPEEDS
ANALYSIS OF VARIANCE RESULTS
SOURCE df SS MS F p r2
MODEL 17 10.6589 0.6269 3.79 .0001 .3845 ERROR 103 17.0600 0.1656 TOTAL 120 27.7190
MODEL LINJ = INT + Bl(TEAM) + B2(AGE) + B3(HT) + B4(LEANWT) + B5(KEAKG] + B6(KEADIF) + B7(KEBKG) + BS(KEBDIF) + B9(KECKG) + BlO(KECDIF) 64
TABLE 21
RESULTS OF THE CORRELATION OF AEROBIC CAPACITY AND MUSCULAR STRENGTH VARIABLES WITH LOWER INJURIES (LINJ)
60 DEGREES/SECOND
ANALYSIS OF VARIANCE RESULTS
2 SOURCE df SS MS F P r
MODEL 5 1.5643 0.3128 1.93 .1164 .2259 ERROR 33 5.3587 0.1623 TOTAL 38 6.9230
MODEL LINJ = INT + Bl(TEAM) + B2(AGE) + B3(V02LIT) + B4 t KEAKG)
270 DEGREES/SECOND
ANALYSIS OF VARIANCE RESULTS
2 SOURCE df SS MS F P r
MODEL 5 1.5822 0.3164 1.96 .1116 .2285 ERROR 33 5.3408 0.1618 TOTAL 38 6.9230
MODEL LINJ = INT + Bl(TEAM) + B2{AGE) + B3(V02LIT) + B4(KECKG) CHAPTER V
DISCUSSION
This study was intended to investigate the influence of several physical and physiological variables on the incidence of injury in
athletics. For this reason, the results and discussion are focused
on three areas, (a) incidence of athletic injuries, (b) comparison
of injured and uninjured athletes, and (c) correlation of physical and physiological variables with injury.
Incidence of Athletic Injuries
Male wrestling resulted in the highest rate of total injuries per athlete. Male wrestling has often been characterized by high
injury rates. In a study of 163 collegiate wrestlers, Roy (63)
reported a rate of total injury (1.42 injuries per athlete) very
similar to this study. Male football and female gymnastics have also been cited as sports with a high frequency of athletic injuries.
Studies of scholastic athletes by Garrick and Requa (20) and by
Clarke and Buckley (11) place male wrestling, male football and female gymnastics in the top four sports of the sports included in this study for total injury rate, as seen in Table 22. It should be mentioned that injuries are often defined differently with regard to
severity of time loss in various studies. For this reason it is more practical to observe relative ranking as opposed to comparing absolute
65 TABLE 22
RANKED TOTAL INJURY RATE (TINJRATE) BY TEAM AS CITED IN THE LITERATURE
(TINJRATE) (TINJRATE) * # TOTAL INJURIES # TOTAL INJURIES TEAM PER ATHLETE TEAM PER ATHLETE
Male Football 0.81 Male Wrestling 0,36
Male Wrestling 0,75 Female Gymnastics 0.28
Female Gymnastics 0.40 Male Ice Hockey 0.27
Female Cross Country 0,35 Male Football 0.25
Female Track 0.35 Male Basketball 0.20
Male Track 0.33 Female Basketball 0.20
Male Basketball 0.31 Female Track 0.12
Female Basketball 0.25 Female Volleyball 0.11
Female Volleyball 0.10 Male Track 0.10
Female Field Hockey 0,06
* [Data from Garrick and Requa, 1978 (20),]
**[Data from Clarke and Buckley, 1980 (11).] 67 injury rates. In fact, the much lower injury rates described in the
Clarke-Buckley study are due mainly to the fact that for the injury to be recognized and recorded the athlete had to miss one entire week of participation. The rates reported by Garrick and Requa (20) should be comparable to this study in that a similar definition of injury was used. In general, the total injury rates in this study were consistently higher than in the Garrick-Requa study.
Table 6 also demonstrates that the total injury rates of five teams (male wrestling, female gymnastics, male football, female volleyball and male track) are much higher than the remaining six teams. This indicates that more attention should be focused on these five teams with regard to injury prevention. Two teams show surprisingly different ranks in comparison to the results of the Garrick-Requa study (20). Female volleyball ranked fourth and female cross country ranked eleventh in this study, versus ninth and fourth respectively in the study of high school athletes. In comparison with the Clarke-Buckley study (11), again some teams varied greatly. Male track proved to sustain injuries at a much higher rate in this study. This high rate of total injuries per athlete for male track may be biased due to the fact that almost all subjects were high power, high risk athletes. That is they all competed in the high jump or short sprints, and may have naturally been more susceptible to injury. If all the members of the team had been included, the value may have been considerably lower. Male ice hockey on the other hand, was ranked much lower in this study than in the Clarke-Buckley study (11). The sport of ice hockey was 68 was interesting to follow. Overall, ice hockey had just as many
total "episodes" as did any other sport, but very seldom did the
episodes result in the loss of any practice or game time. Since
injuries were defined as episodes resulting in one day time loss,
very few hockey injuries were included. This in some way may account
for the lower incidence of injuries in ice hockey.
The rate of lower injuries followed the same relative pattern
as the rate of total injuries. The first five teams were the same
in both instances with rates considerably higher thatn the remaining
six teams.
The six teams that ranked highest in total injury rate all
demonstrated greater than a 50 percent probability of sustaining
at least one total injury. It is interesting to note that male
track, ranked fifth in total injury rate, ranked first in total
injury probability. Even though the team averaged less than one
injury per .athlete, almost 75 percent of the team experienced at
least one injury, Male football on the other hand, ranked third in
total injury rate with a rate of 1.06 injuries per athlete, but only
50 percent of the individuals sustained a total injury. This points out that a team does not necessarily have to have a high number of
injuries per athlete to disrupt the continuity of the program.
The probability of lower injuries displayed a pattern similar to the probability of total injuries. Only two teams, male track and female gymnastics, exhibited a probability of over 50 percent of an individual sustaining a lower injury. 69
Comparison of Injured and Uninjured Athletes
Body composition. In a study by Pollock and co-workers (59) of the influence of body composition variables and exercise duration on injury, they observed age, height, body weight and percent body fat.
The only characteristic that demonstrated a significant difference in means between the injured and uninjured participants was percent body fat. The injured group had a mean body fat of 18.3 percent, while the uninjured group had a mean body fat of 12.2 percent. This was in a population of male recreational runners, not in an athletic population, in a similar study by Kowal (40) of female military recruits, the same observation was made. The group of recruits that was identified as having sustained injuries as a result of a training program proved to have a significantly higher percent body fat. This however, was not the case in this study of collegiate athletes. In fact, the uninjured groups of athletes, both male and female, had a higher mean percent body fat than did the injured groups. This discrepancy may be related to either changes in body composition that occur through the course of a season, or possibly differences in exposure time in practice and game situations. Body composition was measured only once at the beginning of the study, and may have changed due to diet or training variations in some athletes more than others.
But more likely this might be explained by the fact that those athletes who gain the most exposure time in practice and games are also the athletes in the best physical condition. This increase in exposure time is also increasing their chances of being injured. So 70
the injured group could contain more starting players, players with
a lower percent body fat.
Aerobic capacity. Several references were previously cited in
which it was proposed that better conditioned athletes would be less
susceptible to some athletic injuries. The results in Table 1 2 do
not fully support this proposal. The injured group actually
demonstrated an absolute maximal oxygen consumption higher than
the uninjured group, with respect to both total and lower injuries.
This would suggest that the injured group of athletes was a better
conditioned group. When oxygen consumption was expressed per kilogram of body weight, the uninjured group did show a slightly higher mean. The results of Kowal's study (40) showed that the group of recruits that had sustained injuries had a higher maximal oxygen consumption than the recruits free of injury. Pollock and co-workers
(59) demonstrated a higher maximal oxygen consumption for the group of runners that remained free of injuries as compared to the injured group, although the difference was not statistically significant.
Obviously more research must be done in this area to determine if aerobic conditioning can influence the occurrence of injury, or whether injuries simply occur to the athlete who is in the "wrong place at the wrong time," regardless of physical conditioning.
Muscular strength. No statistical differences were found in the means between the injured and uninjured male athletes for any strength variable. These results are contradictory to those of Burkett (8) and Liemohn (41). As previously mentioned, both of these studies showed differences in bilateral symmetry of knee flexion strength and differences in the ratios of flexion to extension strength. The 71
reason for this contradiction may be due to the fact that both studies
were relating strength measurements to one specific injury, hamstring
strain. In this study, however, athletes were not singled out by a
specific diagnosis. An athlete could be classified as injured by
many different types of lower limb injuries.
The muscular strength results of the females did show some
statistical differences between the injured and uninjured groups.
The strength of the extensors of the knee joint, as characterized by
the sum of the two peak torques per kilogram of body weight, was
consistently higher in the Injured group. This difference became
more obvious with increasing speed. This does not suggest that the
injuries were caused by the fact that the subjects had strong quadriceps.
It does demonstrate that strong quadriceps cannot guarantee an athlete will not sustain lower limb injuries, it also may have been affected
again by the difference in exposure time, which was not taken into
consideration in this study. These results are in direct contra
diction to the results of the study by Kowal (40), who also investi
gated the influence of leg strength. Kowal found those subjects
free from injury had a mean leg strength (95.7 kg.) significantly
higher than that of the injured group of subjects (91.2 kg.). It was felt that limited leg strength as a result of poor prior conditioning
contributed to the incidence of injury.
The ratio of flexion to extension strength did appear to differ between the two groups (Table 14). The injured group consistently demonstrated a lower ratio, again with the difference becoming more obvious with increasing speed. This would suggest that in females. 72 the relationship between antagonistic muscle groups should be given
consideration before the season progresses as a possible preventive
measure. It also suggests that higher speeds of contraction should
be used in relating muscular strength variables to lower injury.
Correlation of Physical and Physiological Variables with Injury
Body composition, aerobic capacity and muscular strength indepen
dently. Tables 16, 17 and 18 show the results of the correlation of
the different types of variables with total or lower injury. In
all seven models a significant relationship was identified at the
0.05 level. This is evidence in support of the first three experi mental hypotheses stated in Chapter III concerning the correlation
of body composition variables, aerobic capacity variables, and muscular strength variables with the occurrence of athletic injuries.
Body composition and aerobic capacity were similar in that they
could account for nearly 30 percent of the variability in the
occurrence of total injury (TINJ) and lower injury (LINJ). Even though this may seem relatively low, the body composition models were correct, when applied to the same population on which they were derived, in predicting total injury in 70 percent of the cases and in predicting lower injury in 79 percent of the cases. For comparison, predictions on which athletes would be injured during the season were calculated by two other methods. First hy assuming all or none of the athletes would be injured; and second by random prediction.
Assuming all athletes would complete the season without injury was correct in predicting total injury in 52 percent of the cases, while
random prediction was correct in 46 percent of the cases. It appears, therefore, that the ability of the models to identify those athletes who will or will not sustain injury, is much better than a system of chance. The aerobic capacity models were correct in identifying the occurrence of total injury in 83 percent of the cases, and of lower injury in 88 percent of the cases. Due to the small number of subjects, and the fewer number of injured athletes, assuming no total injuries would occur was correct in 61 percent of the cases, while random prediction was again correct 46 percent of the time. The muscular strength models accurately predicted about
70 to 75 percent of those athletes who sustained lower injury.
The only study that could be found in the literature that made any attempt at correlating physical or physiological variables to injury was that of Kowal (40), which has been frequently mentioned throughout this text. Kowal used a discriminant analysis function to identify the best combination of variables that differentiated between injured and uninjured subjects. He found that body composition and muscular strength, along with other psychological factors, were correlated with total injury. However, the model he described,
ITINJ = ,507(PHYSICAL FITNESS) + ,683(B0DYWT) - ,662(LEG STRENGTH) -
.552(PERFAT)], could correctly classify only 55 percent of the cases.
Nowhere in the results or discussion was a correlation coefficient or r-sguare mentioned.
Combination of physical and physiological variables. The two combinations of variables including aerobic capacity (Table 19 and 74
Table 21) failed to significantly correlate with injury occurrence.
This may Have been due largely to the small sample sizes. The
combination of body composition and muscular strength (at all speeds
tested) proved to be the model that explained the largest portion of
the variability in lower injury occurrence (Table 20). The model
accounted for 38.5 percent of the variability in lower injury (LINJ),
This is in support of the fourth experimental hypothesis that concerned
the correlation of a combination of physical and physiological
variables with injury occurrence. This combination of variables
correctly identified those athletes who subsequently sustained lower
injuries in 79 percent of the cases* or 96 out of 121 athletes.
Random prediction in this case would have correctly predicted approxi
mately 51 percent of the cases* while assuming no injuries would
have been correct about 65 percent of the time.
In general* it can be assumed from the results of this study,
that preseason screening can be beneficial in identifying athletes who may have an increased risk of injury. By measuring variables
associated with the body composition, aerobic capacity* or muscular
strength of the athletes, anywhere from 70 to 88 percent of the time the athlete could be correctly identified as to whether they would or would not sustain at least one injury requiring the loss of one day of practice or game time. This method appears to be superior to any method presently described in the literature. CHAPTER VI
SUMMARY AND CONCLUSIONS
The purpose of this study was to investigate the influence of
body composition, aerobic capacity and muscular strength on the inci dence of injury in athletics. The results were intended to help identi
fy for coaches, trainers and physicians, areas in which physical condi tioning may relate to athletic injuries. Thereby, through proper pre
season screening and physical training, the probability of an athlete
sustaining an injury might be reduced.
The 171 participants in the study were all varsity athletes at
The Ohio State University representing eleven different male and female athletic teams. The athletic teams varied as to the rate of injuries
sustained during one competitive season. Some teams incurred injuries at a rate of four to five times that of the less frequently injured teams. The probability of one athlete from a specific team sustaining an injury tended to be independent of the mean injury rate for that team. This errphasized the need to consider not only injury rates, but injury probabilities as well. More attention needs to be given to the training programs of those athletes who participate on teams with high injury rates and probabilities.
When athletes were classified as injured or uninjured as a result of the competitive season, few differences could be found between their physical characteristics. Those physical characteristics that
75 76
did show differences were height in males and body weight, lean weight,
ventilation, maximal oxygen consumption and quadriceps strength in
females. These results did not however, always characterize the
uninjured group as being physically superior, indicating that physical
conditioning cannot guarantee the prevention of injury.
No significant relationship was found between any physical
characteristics and the frequency of total or lower injuries. The
frequency with which athletes were injured tended to be skewed and
seemed confounded by the increased susceptibility of injured athletes
to reinjury. Significant relationships were found between physical
characteristics and the probability of a single athlete to sustain
an injury within their own sport. Individually it appears as though
body composition and aerobic capacity data provide a somewhat better
relationship with injury than do muscular strength data. The highest
fraction of the variability in lower injuries was explained by the
combination of body composition and muscular strength variables.
Conclusions. Within the limitations of this study, the following
conclusions seem justified.
1. Emphasis should be placed on preventive sportsmedicine in
all sports, but especially male wrestling, male track, female gymnas
tics, male football and female volleyball,
2. Those athletes that sustain injury tend to be slightly older, taller and heavier, with considerably more lean weight.
3. Anywhere from 20 to 40 percent of the variability in injury probability can be explained by the variability in physical character istics. 4. Physical and physiological characteristics can be used for the identification of athletes who possess a high risk of injury.
5. Superior physical conditioning in and of itself, cannot guarantee the prevention of athletic injury due to the extraneous consequences characteristic of sport.
Recommendations. Upon completion of this study the following recommendations have been proposed.
1. Perform a similar study concentrating on those sports which have been found to result in high injury rates and probabilities.
2. Perform a similar study using a repeated measures design to follow changes in physical and physiological characteristics throughout the competitive season.
3. Perform a similar study in which exposure time in practice and games is recorded and adjusted for in the statistics.
4. Perform a similar study including other variables such as flexibility, fiber type, reaction time or fine motor coordination to explain a larger portion of the variability in injuries. BIBLIOGRAPHY BIBLIOGRAPHY
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14. Ekblom, B., P.O. Astrand, B. Saltin, J. Stenberg, and B. Wallstrom. Effect'.of Training on the Circulatory Response to Exercise. Journal of Applied Physiology 24: 518-528, 1968.
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16. Eriksson, E. Sports Injuries of the Knee Ligaments: Their Diagnosis, Treatment, Rehabilitation and Prevention. Medicine and Science in Sports 8(3): 133-144, 1976.
17. Ferstle, J. (ed.) Action Arena, Athletes and Their Knees. The Physician and Sportsmedicine 6(3): 129-133, 1978.
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2 0 . Garrick, J.G., and R.K. Requa. Injuries in High School Sports. Pediatrics 61: 465-469, 1978.
2 1 . Gendel, E.S. Lack of Fitness a Source of Chronic Ills in Women. The Physician and Sportsmedicine 6(2): 85-95, 1978.
22. Gleim, G.W., P.A. Witman, and J.A. Nicholas, Indirect Assessment of Cardiovascular "Demands" using Telemetry on Professional Football Players. American Journal of Sports Medicine 9(3): 178-183, 1981.
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25. Goldfuss, A.J., C.A. Morehouse, and B. F. Levfan. Effect of Muscular Tension on Knee Stability. Medicine and Science in Sports 5(4): 267-271, 1973.
26. Gollnick, P.D. Free Fatty Acid Turnover and the Availability of Substrates as a Limiting Factor in Prolonged Exercise. Annals of the New York Academy of Science 301s 64-71, 1977.
27. Gollnick, P., R, Armstrong, B. Saltin, C. Saubert, W. Sembrowich, and R. Shepherd. Effect of Training on Enzyme Activity and Fiber Composition of Human Skeletal Muscle. Journal of Applied Physiology 34(1): 107-111, 1973.
28. Gonyea, W.J., G. C. Ericson, and F. Bonde-Petersen, Skeletal Muscle Fiber Splitting induced by Weightlifting Exercise in Cats. Acta Physiologica Scandinavica 99: 105-109, 1977,
29. Gordon, E. Anatomical and Biochemical Adaptations of Muscle to Different Exercises. Journal of the American Medical Associa tion 201: 755-758, 1967.
30. Guyton, A.C. Textbook of Medical Physiology, 5th ed. Philadelphia: W. B, Saunders Company, 1976.
31. Hage, P. Strength: One Component of a Winning Team. The Physi cian and Sportsmedicine 9(8): 115-120, 1981.
32. Helwig, J.T., and K.A. Council, (ed.) Statistical Analysis System User’s Guide, 1979 Edition. Cary, North Carolina: SAS Institute, Incorporated, 1979.
33. Hermansen, L., and M. Wachtlova. Capillary Density of Skeletal Muscle in Well-Trained and Untrained Men. Journal of Applied Physiology 30(6): 860-863, 1971.
34. Hislop, H., and J. Perrine. The Isokinetic Concept of Exercise. Physical Therapy 47: 114-117, 1967.
35. Ho, K ., R. Roy, J, Taylor, W. Huesner, W. Van Huss, and R. Carrow, Muscle Fiber Splitting with Weightlifting Exercise. Medicine and Science in Sports 9(1): 65, 1977.
36. Holloszy, J.O. Effects of Exercise on Mitochondrial Oxygen uptake and Respiratory Enzyme Activity in Skeletal Muscle. Journal of Biological Chemistry 242: 2278-2282, 1967.
37. Holloszy, J.O. Adaptation of Skeletal Muscle to Endurance Exercise. Medicine and Science in Sports 7(3): 155-164, 1975.
38. Hoppeler, H., P. Luthi, H. Claasen, E. Weisel, and H. Howald. The Ultrastructure of the Normal Human Skeletal Muscle. Pflugers Archives 344: 217-232, 1973. 82
39. Klafs, C.E., and D.D. Arnheim, M o d e m Principles of Athletic Training. 3rd ed. St. Louis: C.V. Mosby Company, 1973.
40. Kowal, D.M. Nature and Causes of injuries in Women Resulting from an Endurance Training Program, American Journal of Sports Medicine 8(4): 265-269, 1980.
41. Liemohn, W. Factors Related to Hamstring Strains. Journal of Sports and Physical Fitness 18: 71-76, 1978.
42. Lundegren, H. Changes in Skinfold and Girth Measures of Women Varsity Basketball and Field Hockey Players. Research Quarterly 39: 1020-1024, 1968.
43. MacDougall, J.D., D.G. Sale, J.R. Moroz, G.C.B. Elder, J.R. Sutton, and H. Howald. Mitochondrial Volume Density in Human Skeletal Muscle Following Heavy Resistance Training. Medicine and Science in Sports 11(2): 164-166, 1979.
44. MacDougall, J.D., G. R. Ward, D.G. Sale, and J.R. Sutton. Biochemi cal Adaptation of Human Skeletal Muscle to Heavy Resistance Training and Immobilization. Journal of Applied Physiology 43(4): 700-703, 1977.
45. Mann, G.V,, H.L. Garrett, A. Farhi, H. Murray, and F.T. Billings. Exercise to Prevent Coronary Heart Disease. American Journal of Medicine 46: 12-27, 1969.
46. Mayhew, J.C. , and P.M. Gross. Body Composition Changes in Young Women with High Resistance Weight Training. Research Quarterly 45; 433-440, 1974.
47. Michielli, D.W., R.A. Stein, N. Krasnow, J.R. Diamond, and B. Horwitz. Effects of Exercise Training on Ventricular Dimen sions at Rest and During Exercise. Medicine and Science in Sports 11: 82, 1979.
48. Miyashita, M,, and H. Kanshisa. Dynamic Peak Torque Related to Age, Sex and Performance. Research Quarterly 50: 249-255, 1979.
49. Mole, P., L. Oscai, and J. Holloszy. Adaptation of Muscle to Exercise Increase in Levels of Palmityl CoA Synthetase, Carni tine Palmityltransferase, and Palmityl CoA DeHase, and in the Capacity to Oxidize Fatty Acid. Journal of Clinical Investi gation 50: 2323-2330, 1971.
50. Moody, D., J. Wilmore, R. Girandola, and J, Royce, The Effects of a Jogging Program on the Body Composition of Normal and Obese High School Girls. Medicine and Science in Sports 4: 210-213, 1972. 83
51. Moore, M. Brief Reports: Preseason Conditioning Reduced Knee Injuries. The Physician and Sportsmedicine 10(1): 25, 1982.
52. Morganroth, J., B. Maron, W. Henry, and S. Epstein. Comparative Left Ventricular Dimensions in Trained Athletes, Annals of Internal Medicine 82: 521-524, 1975.
53. Nicholas, J.A. Injuries to Knee Ligaments, Relationship to Looseness and Tightness in Football Players. Journal of the American Medical Association 212(13): 2236-2239, 1970.
54. Nicholas, J.A., A.M. Strizak, G. Veras. A Study of Thigh Muscle Weakness in Different Pathological States of the Lower Extremity. American Journal of Sports Medicine 4(6): 241-248, 1976.
55. Ouellet, R., H.P. Levesque, and C.A. Laurin, The Ligamentous Stability of the Knee: An Experimental Investigation. Canadian Medical Association Journal 100: 45-50, 1969.
56. Parr, R. B,, R. Hoover, J.H. Wilmore, D. Bachman, and R.K. Kerlan. Professional Basketball Players: Athletic Profiles, The Physician and Sportsmedicine 6(4): 77-84, 1978,
57. Pattengale, P.K., and J.O. Holloszy. Augmentation of Skeletal Muscle Myoglobin by a Program of Treadmill Running. American Journal of Physiology 213: 783-785, 1967.
58. Pollock, M.L. Submaximal and Maximal Working Capacity of Elite Distance Runners. Part 1: Cardiorespiratory Aspects. Annals of the New York Academy of Science 301: 310-322, 1979.
59. Pollock, M.L., L.R. Gettman, C.A. Milesis, M.D. Bah, L. Durstine, and R.B. Johnson. Effects of Frequency and Duration of Training on Attrition and Incidence of Injury. Medicine and Science in Sports 9(1): 31-36, 1977.
60. Pope, M.H., R.J. Johnson, D.W. Brown, and C. Tighe. The Role of the Musculature in Injuries to the Medial Collateral Liga ment. Journal of Bone and Joint Surgery 6lA(3): 398-402, 1979.
61. Rasch, P.J., and R.K. Burke. Kinesiology and Applied Anatomy, 6th ed. Philadelphia: Lea and Febiger, 1978.
62. Ritchey, S.J, The Athlete and His Knee. Journal of Sports Medicine and Physical Fitness 3: 239, 1963.
63. Roy, S.P. Intercollegiate Wrestling Injuries. The Physician and Sportsmedicine 7(11): 83-91, 1979.
64. Sharp, R.L,, J.P. Troup, and D.L. Costill. Relationship between Power and Sprint Freestyle Swimming. Medicine and Science in Sports and Exercise 14(1): 53-56, 1982. 84
65. Thompson, C.W., E. R. Buskirk, and R.F. Goldman. Changes in Body Fat, Estimated from Skinfold Measurements of College Basketball and Hockey Players during a Season. Research Quarterly 27: 418-430, 1956.
66. Thorstensson, A., B. Hultin, w. VonDobeln, and J. Karlsson. Effect of Strength Training on Enzyme Activities and Fibre Characteristics in Human Skeletal Muscle. Acta Physiologica Scandinavica 96: 392-398, 1976.
67. Tipton, C.M., R.D, Matthes, J.A. Maynard, and R.A. Carey. The Influence of Physical Activity on Ligaments and Tendons. Medicine and Science in Sports 7(3): 165-175, 1975.
68. White, A.A., and I.G. Raphael. The Effect of Quadriceps Loads and Knee Position on Strain Measurements on the Tibial Collat eral Ligament. An Experimental Study on Human Amputation Specimens. Acta Orthopaedia Scandinavica 43: 176-187, 1972,
69. Wilmore, J.H. The Use of Actual, Predicted and Constant Residual Volumes in the Assessment of Body Composition by Underwater Weighing, Medicine and Science in Sports 1(2): 87-90, 1969.
70. Wilmore, J.H. Alterations in Strength, Body Composition, and Anthrometric Measurements Consequent to a 10-Week Weight Training Program. Medicine and Science in Sports 6: 133-138, 1974.
71. Wilmore, J.H,, R.B, Parr, and W.L, Haskell. Football Pro's Strengths and CV Weaknesses - Charted. The Physician and Sportsmedicine 4: 44-54, 1976.
72. Wilmore, J.H,, J. Royce, R. Girandola, F. Katch,. and V. Katch. Body Composition Changes with a 10-Week Program of Jogging. Medicine and Science in Sports 2: 113-117, 1970. APPENDIX A
ERGO-PNEUMOTEST CALIBRATION PROCEDURE
85 CALIBRATION 86
A. Select calibration program by pressing J E |
♦RESPONSE* CALIBRATION EXPLANATION FOR CALIBRATION ? 0 = NO 1 = YES
1. Press
♦RESPONSE* PHASE 7
2. Place "CALIBRATION" overlay over keyboard.
3. Select inspired-expired phase by pressing K
♦RESPONSE* K = IN AND EX 10 STROKES IN AND EX WITH 1L PUMP
a. Adjust DVM display by turning "KNOB A" so that it reads between -.005 and +.005.
b. Attach 1 liter calibration syringe to the input side of the pneumotachometer.
(Note: The mixing bag should be removed during calibration.)
c. Complete 10 full strokes of the syringe.
♦RESPONSE*
-X.XXXX (mean expired volume) x.xxxx (mean inspired volume)
d. If the two volumes are within 50 ml. of each other press and go on
to step 4.
♦RESPONSE* PHASE ?
If the two volumes are NOT within 50 ml. of each other then perform the following procedure;
If I -X.XXXX) > [ +X.XXXX] then make DVM display more positive by turning "KNOB A". If I -X.XXXX) < [ +X.XXXX) then make DVM display more negative by turning "KNOB A". 87 e. .Complete 10 more full strokes of the syringe and repeat step 3,d,
4. Select minute ventilation phase by pressing | L [ .
♦r e s p o n s e * L = MV 10 STROKES IN AND EX WITH lL PUMP
a. Complete three full strokes of the syringe, INT. b. Press button (Labelled "B") two tines. NULL c. Complete ten slow, full strokes of the syringe in 30 seconds.
(Notes The calculator will automatically respond when the clock reaches 00.30.)
♦RESPONSE* X.XXX (mean minute ventilation)
d. If the volume is with ing 0.950 — 1.050 press RUN ^ STOP * a 9° °n P * ♦RESPONSE* PHASE ?
If the volume is NOT within 0.950 — 1.0 50 then return to step 3.
5. Prepare for gas calibration as follows:
a. Turn power on to 02 and C02 analyzer pumps.
b. Set "KNOB B" to RG (room gas).
c. Set 02 % to +0.0 by adjusting "KNOB C".
d. Set C02 % to +0,0 by adjusting "KNOB D".
e. Attach calibration gas sample to E2 inlet.
f. Set "KNOB B" to E2 (calibration gas).
g. Set 02 % to calibration gas by adjusting "KNOB E".
h. Set C02 % to calibration gas by adjusting "KNOB F",
i. Repeat steps b. - h, until values hold steady,
j. Set "KNOB B" to RG (room gas). 88 6. Select gas calibration phase by pressing | M j
* RESPONSE* M = 02, 002, CO, HE INPUT “ 0 FOR OLD VALUE INPUT PRED. VALUES 02 ?
a. Set "KNOB B" to E2.
b. One last time make sure 02 % and C02 % displays match the calibration gas.
c. Enter predicted (calibration) 02 %, press
♦RESPONSE* C02 ?
d. Enter predicted (calibration) C02 %, press STOP ♦RESPONSE* CO ?
e. Enter 0, press
♦RESPONSE* HE ?
f. Enter 0, press
(Note: The reason the cart asks for concentrations of CO and HE is because it also has the capability of performing lung diffusion tests. However, for our purposes these concentrations are always entered as 0.) SFG. To span the gas press CFG.. ♦RESPONSE* 02 x.xxx C02 x.xxx
02 X.XXX C02 X.XXX 89 h. Allow the calculator to continue to print observing the 02 and C02 concentrations*
If both the 02 and C02 concentrations remain stable in four to five repeated samples then
press and go on to step 6.i. CFG.. •RESPONSE* : Calculator will stop but no response will be printed.
If either the 02 or C02 concentrations do NOT remain stable in four or five repeated samples
then press and
return to step 5.b.
i. Press (letter 0}.
•RESPONSE* 0 = END OF MEASUREMENT DATAS ARE STORED
ERICH JAEGER PNEUMOLAB
PROGRAM = ?
j. Set "KNOB B" to El {draws sample from mixing bag),
k. Remove calibration gas sample bag. APPENDIX B
ISOKINETIC DYNAMOMETER CALIBRATION PROCEDURE
90 91 Table 1. Calculation of torque for torque-channel calibration.
30 Ft.-lb. Scale .
Weight = 5.19 lb.
Torque = 5.19 lb. X 2.75 fit. = 14.27 ft.-lb*'
* Total torque = 14.27 ft.-lb. +6. 5 9 ft.-lb. « 20.86 ft.-lb.
180 Ft.-lb. Scale
Weight = 30.44 lb.
Torque - 30.44 lb. X 2.75 ft. = 83.60 ft.-lb.
* Total torque = 83.60 ft.-lb. + 6.59 ft.-lb. = 90.19 ft.-lb.
360 Ft.—lb. Scale
Weight = 45.26 lb.
Torque - 45.26 lb. X 2.75 ft. = 124.47 ft.-lb.
* Total torque = 124.47 ft.-lb. + 6.59 ft.-lb. = 131.06 ft.-lb.
I * Includes the torque produced by the T-bar alone which is assumed to be 6.59 ft.-lb. (4).]
The CALIBRATION procedure which follows requires the three torque scales to be calibrated independently. Therefore, Table 2 includes the levels to which the graphic recording should reach, given that each of the torque scales are chosen during the calibration procedure. 92 Table 2. Evaluation of torque on each scale during the calibration procedure.
Scale . Torque * Minor Divisions
30 ft.-lb. 20.86 ft.-lb. 20.9
180 ft.-lb. 90,19 ft.-lb. 15.1
360 ft.-lb. 131.06 ft.-lb. 10.9
I * Each major division is divided into three minor divisions. ]
CALIBRATION OF THE TORQUE-CHANNEL
A. Preparation of the Recorder
Before the CALIBRATION procedure can be performed, the recorder must be "zeroed". This process assures that the baseline of the torque channel remains constant regardless of which ft.-lb. scale is selected. The
"zeroing" procedure is as follows:
' Al. Turn on the power to the RECORDER and SPEED SELECTOR.
A2. Set the DAMPING of the RECORDER to 2. ■
A3. Remove all attachments from the input shaft of the dynamometer, and turn the face of the dynamometer away from -tbe benches.
A4. Set the SPEED SELECTOR to 30 degrees/second ( 5 RPM3 .
A5. Set the FT.-LB. SCALE to 180.
A5.a. Set the CHART SPEED to 5 mm. /second to advance the paper.
A5.b. . Adjust the stylus on the torque channel using the "ZERO ADJUST" knob so that it is right on the baseline.
A5,c. Set the FT.-LB. SCALE to 30 FT.-LB.
A5.d. Stop the paper drive. 93 I At this point If the stylus does not deflect go on to Preparation of the Dynamometer, if the stylus does deflect proceed with Step A6. ]
A6. Identify the potentiometer marked "ZERO NULL" on the upper right hand side of the RECORDER housing. I A6.a. Set the CHART SPEED to 5 nun./second
A6.b. Adjust the position of the stylus to the baseline by ‘ turning the "ZERO NULL" potentiometer. (Turning the potentiometer clockwise raises the stylus, turning the potentiometer counterclockwise lowers the stylus.)
A6.c, Stop the paper drive.
A6.d. Repeat beginning with Step A5.
Preparation of the Dynamometer
Bl. Attach the ".LONG INPUT ADAPTER" to the dynamometer. Insert the CALIBRATION arm (or "T-bar") into the LONG INPUT ADAPTER. The length of the T-bar assembly should be 2.75 ft. (Measured from the center of the input shaft of the dynamometer to the center of the "T" portion of the T-bar.) '
B2. Place the appropriate amount of weight onto the T-bar to cali brate each torque scale (as indicated in Table 1.)
Calibration of the Dynamometer/Recorder
Cl. Set the SPEED SELECTOR to 30 degrees/second (5 RPM) .
C2. Set the baseline of the torque channel using the "ZERO ADJUST" knob.
• C3. Set the CHART SPEED to 5 mm. /second to advance the paper.
C4. Bring the weighted T-bar up to speed and allow it to drop passing the horizontal position, catching it just before it contacts the floor.
C5. Stop the paper drive.
C6. Observe the graph on the RECORDER. 94 I At this point if the torque recorded on the RECORDER is equal to the calculated torque go on to the next torque scale. Once all three scales have been independently calibrated, go on to further CALIBRATION or OPERATION. If however, the achieved torque and calculated torque are not equal, proceed with Step C7. 3
C7. Identify the potentiometers marked "30", "180" and "360" on the upper right hand side of the RECORDER housing.
C7.a. If the recorded torque is greater than the calculated torque, turn the potentiometer counterclockwise. If the recorded torque is less than the calculated torque, turn the potentiometer clockwise.
C7Pb. Repeat beginning with Step C2.
CALIBRATION OF THE POSITION-CHANNEL
A. Complete CALIBRATION of the Torque-channel.
B. Calibration of the Dynamometer/Recorder
Bl. Identify the goniometer (black dial on the face of the dynamometer).
B2. Select CCW on the position channel.
B3. Select the 150 (300) DEGREE SCALE.
B4. Turn the goniometer until 0 degrees is aligned with, the small white marker in the six-o’clock position.
B5. Set the stylus to the baseline of the position channel using the "ZERO ADJUST" knob.
B6. Turn the goniometer counterclockwise through 150 (300) degrees.
[ At this point if the position tracing is aligned with the upper line of the position channel go on to the other position scale. Once both scales are calibrated go on to further CALIBRATION or OPERATION. If however, the tracing is not aligned with the upper Line of the position channel procede with Step B7. ]
B7. Identify the position channel CALIBRATION screw on the face of the RECORDER. 95 B7.a. If the position tracing lies above the upper line of the position channel turn the screw counterclockwise. If the position tracing lies below the upper line of the position channel turn the screw clockwise.
B7.b. • Repeat beginning with Step B4.
[ Note: The speed setting of the dynamometer is irrelevant during calibration of the Position-channel. ]
CALIBRATION OF SPEED
A. Complete CALIBRATION of the Torque-channel.
B. Complete CALIBRATION of the Position-channel.
C. Calibration of the Dynamometer/Speed Selector
Cl. Remove the T-bar from the LONG INPUT ADAPTER,
C2. Insert the knee testing bar into the L0N6 INPUT ADAPTER.
C3. Set the SPEED SELECTOR to 60 (300) degrees/second.
C4. Crank the dynamometer 10 revolutions maintaining torque throuhout all the revolutions.
C5. Time the 10 revolutions with a stopwatch.
[ At this point if the time it takes to complete the revolutions is equal to the times indicated in Table 3 below go on to another speed. Once at least two speeds have been calibrated go on to OPERATION. If however, the time does not correspond with that calculated proceed with Step C6. 3
C6. Remove the cover of the SPEED SELECTOR.
C7. Identify the R77 potentiometer.
C7,a. If the speed indicated is too high, turn the potentiometer counterclockwise. If the speed indicated is too low, turn the potentiometer clockwise.
C7.b. Repeat beginning with Step C3. 96 Table 3. Time intervals for ten revolutions at various selected angular speeds.
Speed Time
60 degrees/second 60.0 seconds
180 degrees/second 20.0 seconds
300 degrees/second ‘ 12.0 seconds
At this point all CALIBRATION has been completed. Under normal use, the CYBEX II system holds its calibration well. The procedures described for calibration of the Position-channel and Speed need only be done every three months or so. (This will vary from laboratory to laboratory based on use and other factors.) Calibration of the Torque—channel and zeroing the RECORDER, however, should probably be done once per month or more, again depending primarily on use.' APPENDIX C
RAW DATA OF SUBJECTS BY TEAM
97 RAH DATA SUBJECTS BY TEAM EXIN160) EXTNl1801 EXTNI270I F^XN(60) 1801 Fk«NI2701 lONun AGE HT BOOYtlT PERFAT VENTLN V02LIT HR R L R L V" TINJFREQ LINJFREQ
102.01 19 198 9% 6 3 . . • 366 325 260 228 179 171 228 24% 171 179 130 134 0 .0 0 .0 102.02 20 201 102 19 9 • • • 2%% 252 183 171 130 126 179 179 126 13% 89 94 0.0 0.0 102.03 20 190 81 79 . • • 268 252 175 167 122 n o 163 163 13B 130 110 110 2 5 .0 2 5.0 102.0% 22 175 86 10 3 . • • 236 252 183 163 138 11% 155 187 134 138 102 114 0 .0 0 .0 102.05 18 188 88 12 % . • • 293 301 212 212 146 142 195 203 142 151 118 114 0 .0 0 .0 102.0% 20 201 103 7 8 * . • 285 325 199 228 1%2 163 236 24% 179 191 146 155 2 5 .0 2 5.0 1 02.OT 21 206 93 13 0 • 325 33% 236 220 171 155 228 228 163 163 13% 122 2 5 .0 2 5 .0 102.08 20 211 97 20 0 . • ■ 285 260 187 171 146 13% 179 195 130 138 114 122 0.0 0.0 102.09 18 180 71 % 7 - . * 236 236 187 171 130 106 130 130 122 106 102 89 0.0 0.0 102.10 19 180 75 11 2 . . • 252 260 187 19.5 138 142 146 146 122 130 98 106 0 .0 0 .0 102.11 20 211 95 6 9 • . • 309 325 2%% 22% 179 171 179 195 130 142 114 114 25.0 25.0
107.01 18 188 86 « • • 285 301 216 203 1%6 163 163 155 130 122 89 98 0 .0 0 .0 107.02 18 180 77 m • • 285 2%% 187 179 122 130 146 122 114 110 89 98 0 .0 0 .0 107.03 18 185 101 * « • 382 %07 260 277 175 183 195 187 146 130 106 106 0 .0 0 .0 107.0% 18 196 109 • • « 325 236 212 179 155 130 179 !%6 146 130 126 110 0 .0 0 .0
107.05 20 190 10% • 9 • 293 325 220 228 171 171 163 163 126 122 11% 11% 5 .3 0 .0 107.06 18 198 120 • • • 293 33% 203 260 175 187 171 171 146 146114 11% 15.8 2 1 .4
107.07 21 188 100 m • 9 350 %07 236 277 171 195 203 203 155 146122 122 0 .0 0 .0 107.08 18188 102 • • • 228 236 179 179 126 110 171 155 130 122 102 98 0.0 0.0 107.18 18 190 128 • • • 285 33% 212 236 155 159 195 212 146 146 130 122 5 .3 7.1 107.09 19 198 116 • •• 37% 3%2 2%% 236 179 171 268 24% 212 195 155 155 0.0 0.0 107.10 18 193 111 • • • 293 260 191 183 138 138 179 171 146 142 122 114 0.0 0.0 107.11 IB 190 107 * • • 260 260 171 179 122 122 163 171 126 122 98 102 2 6 .3 2 8 .6
107.12 18 190 112 • m 9 293 293 195 212 1%6 146 179 163 146 146 130 118 10.5 7.1
107.13 18 180 81 • • m 236 195 163 167 126 13% 146 122 110 114 89 85 5 .3 0 .0
107.1% 18 183 85 m 9 9 293 317 212 212 146 151 179 179 122 138 98 106 15.8 2 1 .4
107.15 19 183 83 m m 9 2%% 2%% 179 1%6 122 110 136 155 110 118 9% 98 0 .0 0 .0
107.16 18 185 85 9 • • 187 187 1%6 171 11% 122 106 106 77 102 89 65 10.5 7.1 107.17 18 190 82 • • • 228 268 155 183 110 130 146 130 106 102 89 81 5 .3 7.1 *AII DATA OF SUBJECTS BY TEAM EgfNl 601 EXTNI1801 EXTNI270J Fj^XN160) 180) F^XN1270) IDNUN AGE HT BDDYMT PERFAT VENTLN V02L1T HR R L R L Fr ( TINJFREQ IINJFREQ
110.01 23 175 78 1 2 .0 . . m 212 216 167 155 122 118 163 146 126 114 94 89 0 .0 0 .0 110.02 21 185 78 7 .4 • 277 268 195 191 130 126138 163 114 118 94 94 18.2 20.0 110.03 20 183 75 1 2 .8 • 228 228 151 159 106 110 146 146 98 114 73 89 0.0 0.0 110.04 22 180 87 13.9 . . « 195 212 183 175 142 134 163 163 130 118 106 102 0 .0 0 .0 110.05 21 180 83 9 .7 • 232 220 167 151 110 no 155 155 114 138 85 94 0.0 0.0 110.06 19 170 68 9 .9 * 199 183 142 134 106 98 151 142 118 114 98 85 0.0 0.0 110.07 18 180 70 14.1 . . * 224 199 146 138 110 102 118 130 89 98 73 77 0.0 0.0 110.08 20 180 69 13.3 • 195 203 130 122 89 89 126 126 89 85 69 69 0 .0 0 .0 110.09 22 178 77 5.9 . . 260 252 187 199 138 138 146 163 114 134110 102 0 .0 0 .0 110.10 22 180 84 15.1 •212 228 159 163 122 118 134 134 114 102 94 85 0.0 0.0 110.11 20180 88 11.1 • 244 236 163 159 130 114 146 155 118 118 98 94 0 .0 0 .0 110.12 19183 75 10.1 • 236 236 159 151 114 106 130 130 n o 106 85 81 0 .0 0 .0 110.13 20 188 85 7 .4 m 244 244 171 171 114 122 171 179 130 138 102 110 9 .1 2 0 .0 110.14 21 190 93 1 0.6 • 293 285 216 203 151 151 179 171 134 130 110 110 9 .1 0 .0 110.15 22 178 84 1 6.6 • 244 236 159 155 114 98163 122 106 98 73 77 9 .1 0 .0 110.16 23175 78 16.1 . . •216 199 146 142 102 102 142 134 106 106 81 81 2 7 .3 2 0 .0 110.17 21 183 76 14.3 • 236 236 167 167 122 118 179 163 130 122 102 05 0 .0 0 .0 110.18 21 183 78 1 2 .8 • 228 260 167 167 126 122 163 163 122 122 102 81 0 .0 0 .0 110.19 21 183 81 8 .2 • 252 244 179 167 126 126 146 146 122 126 98 98 9 .1 2 0 .0 110.20 18 180 71 3 .7 • 220 199 151 138 114 102 114 110 89 98 81 81 0.0 0.0 110.21 20 178 75 13.2 * 191 212 138 146 98 102 130 126 110 106 77 77 18.2 2 0 .0 110.22 21 175 83 14.2 • 236 244 163 163 114 118 146 146 114 114 89 89 0 .0 0 .0
10 VO RAH OATA OF SUBJECTS BY TEAM EXTNI601 EXTNU801 EXTN12701 FLXNI1801 2701 IDNUN AGE HT BODYWT PERFAT VENTLN V02LIT HR R L R L R L Fkm6 V R L Fr* TINJFREQ LINJFREQ
117.01 19 170 68 8 .6 * #• 220 236 167 187 122 122 130 138 98 110 73 77 10.0 1 0 .0 117.02 20 183 81 • • •• 236 266 163 187 122 130 171 163 130 118 89 85 10.0 10.0 117.03 20 175 66 1 5 .7 * •• m m • • • • ••• • » • 10.0 10.0 117.0% 19 173 67 6 .5 m • • 195 268 166 151 122 116 166 138 102 118 81 96 10.0 10.0 117.05 22 183 72 •• • • 285 266 212 175 166 130 179 171 138 138 116 12 2 10.0 10.0 117.06 19 178 65 7 .2 •• 191 203 155 151 116 116 126 102 102 89 85 77 10.0 10.0 117.07 21 179 96 • • • • 309 309 195 203 136 162 179 171 130 130 102 106 0 .0 0 .0 117.08 18 175 69 9 .5 • • • • ••• «•• • « • « 2 0 .0 2 0 .0 117.09 21 155 70 • ••• 252 268 187 187 138 138 171 171 122 126 102 102 0 .0 0 .0 117.10 20 180 75 16.7 • *• 285 325 195 212 166 166 163 155 130 130 98 98 2 0 .0 2 0 .0 117.11 20 181 75 • * m • 268 277 187 191 138 138 187 179 138 136n o 116 0 .0 0 .0
218.01 18 173 61 • 9 1 .3 2.21 197 166 126 106 102 73 73 85 85 69 61 53 69 0 .0 0 .0
218.02 18 185 87 0 1 01.2 3 .3 9 200 203 236 155 159 118 118 155 155 122 122 96 98 2 0 .0 2 0 .0 218.03 20 160 52 • 9 3 .3 3 .03 198 138 166 89 98 61 69 81 96 61 57 65 69 10.0 0 .0 218.06 18 170 57 • 8 1 .7 2 .7 6 195 167 151 106 96 69 69 102 106 89 81 69 65 10.0 0 .0 218.05 18 183 66 • • * 163 171 1 IB 116 81 81 102 102 81 77 61 57 10.0 0 .0 218.06 20 175 70 • 9 9 .8 3 .6 9 198 220 195 167 130 118 98 122 116 102 98 85 81 1 0 .0 2 0 .0 218.07 19180 77 • 9 0 .8 3 .2 8 192 187 175 130 130 89 89 126 130 98 102 73 77 0 .0 0 .0 218.08 21 168 59 • 8 5.8 2 .06 188 155 151 96 96 61 65 102 83 73 73 57 57 1 0.0 0 .0 218.09 19 178 68 • • * • 175 175 118 LIB 77 81 102 102 73 77 57 61 0 .0 0 .0 218.10 20 178 71 9 7 .3 3.05 192 171 155 122 110 89 81 122 118 96 89 73 73 2 0 .0 6 0 .0 100 R A H DATA SUBJECTS BY TEAM
EXTNI60) EXTN1 180) EXTN(27Q) FLXNI60) FLXNt180) FLXN1270I 1DNUM AGE HT BOOYWr PERFAT VENTLN V02LIT HR A L R L R L R LR L R L TINJFREQ L1NJFREQ
119.01 IS 168 58 9 .4 • 151 151 102 114 69 73 89 85 81 77 65 61 0 .0 0 .0 119.02 18 169 77 12.2 * 207 212 142 151 106 106 134 130 106 110 77 77 0 .0 0 .0 119.03 20 175 80 11.2 . . • 240 252 155 167 114 122 130 138 n o 114 89 98 0 .0 0 .0 119.04 19 168 65 10.2 • 179 175 118 114 61 77 114 118 73 69 37 49 2 .5 5 .0 119.05 21 192 94 1 2 .0 . . • 260 260 179 179 130 126 179 187 130 130 98 106 5 .0 5 .0 119.06 21 166 56 5 .1 * 175 199 122 130 85 81 85 98 69 69 57 57 2 .5 0 .0 119.07 19 168 58 1 2.9 * 151 163 106 118 73 81 89 98 69 73 53 53 0 .0 0 .0 1 1 9 .OB 18 175 85 1 0 .4 . . • 252 277 155 155 114 106 138 163 118 118 81 81 2 .5 5 .0 119.09 20 180 78 0«6 • 6 • 220 228 130 155 89 106 114 114 77 77 61 65 5 .0 5 .0 119.10 20 183 87 8*2 • 252 212 175 167 122 110 163 155 126 114 98 85 5 .0 10.0 119.11 19 183 84 10*6 * 195 207 163 175 122 114 155 134 118 106 94 77 2 .5 5 .0 119.12 21 180 80 8* 6 • • * 212 216 163 155 122 114 130 134 98 102 77 81 7 .5 5 .0 119.13 21 179 76 1 3 .4 • •« • .• *• *. • • * 5 .0 5 .0 119.14 20 175 76 5 .0 * 244 268 163 171 118 122 155 179 110 118 85 89 12.5 15.0 119.15 20 170 68 9*6 * • * 183 163 130 110 94 81 159 146 98 102 73 77 0 .0 0 .0 119.16 20 169 69 8*0 * * • 155 163 118 130 89 89 138 110 89 89 81 69 5 .0 0 .0 119.17 19 186 98 14*9 * 228 220 159 155 118 114 151 134 n o 98 85 77 7 .5 10.0 119.18 20 190 103 12*1 . * * 277 268 199 195 146 142 195 203 155 146 126 126 2 .5 5 .0 119.19 21 183 90 2 0 .) • 224 207 142 159 94 98 122 122 85 89 73 69 2.5 0 .0 119.20 20 168 74 9*1 * 216 191 146 138 106 98 122 122 81 81 69 65 2 .5 0 .0 119.21 21 185 85 14*1 * 220 240 163 171 122 118 163 142 114 110 89 85 10.0 15.0 119.22 18 178 69 10*2 • 195 207 122 126 81 98 110 114 73 85 57 69 0 .0 0 .0 119.23 19 184 92 6* 8 • • * 260 268 175 183 122 130 163 171 118 126 89 98 2 .5 0 .0 119.24 18 165 59 10*7 * 191 163 118 118 85 89 114 94 85 73 61 61 0 .0 0 .0 119.25 IB 170 75 9 .8 • 175 159 118 118 81 85 130 138 106 102 77 77 2 .5 0 .0 119.26 19 170 73 6*5 • 203 212 134 142 106 106 138 142 102 106 77 89 2 .5 0 .0 119.27 19 163 64 11.4 • 195 212 122 146 73 77 118 122 85 94 61 65 5 .0 1 0.0 119.28 18 170 66 12.6 * 155 151 106 106 73 69 126 122 94 98 69 73 7 .5 0 .0 119.29 19 174 69 1 4.8 * 130 138 94 106 73 73 85 94 73 53 53 45 0 .0 0 .0 101 RAW DATA SUBJECTS BY TEAM EXTN. 1801 EXTNI2T01 FLXNI601 FJ.XN,180) 270) IONUN AGE HT BODYWT PERFAT VENTLN V02L1T » . £JT“' T R , L R L Fr ' TINJFREQ LtNJFREQ
202.01 IT 173 65 16.1 . . . 183 155 130 96 89 65 90 126 98 96 61 61 0 .0 0 .0 202.02 16 160 63 1 8 .6 . 171 151 117 102 77 69 102 102 69 77 57 53 0 .0 0 .0 202.03 19 175 61 1 6 .6 . . . 166 166 9B 96 69 65 106 106 81 81 65 65 0 .0 0 .0 202.01 21 178 68 18.5 . 151 • 106 • 73 • 130 • 98 • 73 • 0 .0 0 .0 202.05 21 166 62 19.2 . • . 171 163 n o 106 69 73 73 96 65 69 69 53 0 .0 0 .0 202.06 21 166 56 13.8 • . • 163 163 110 106 73 77 B9 96 69 65 57 53 11.1 2 0 .0 2 02 .0 7 20 166 56 1 0 .6 . . . 155 162 102 96 65 65 102 102 77 73 61 53 2 2 .2 2 0 .0 202*06 19 182 69 1 3 .6 . . . 183 179 118 118 89 85 126 122 96 96 77 77 11.1 2 0 .0 202.09 21 188 75 1 2 .6 . . . 155 116 136 116 116 106 122 110 96 96 77 77 2 2 .2 20.0 202.10 22 175 68 1 3 .0 . 171 187 136 130 102 89 126 136 98 106 77 73 11.1 0 .0 202.11 21 182 61 1 6 .6 . . . 136 159 102 116 73 81 118 110 89 85 69 69 0 .0 0 .0 202.12 18 182 66 19.1 • . . 163 171 116 122 85 89 102 98 89 89 61 79 l l . l 0 .0 202.13 16 185 67 . . . . 175 175 126 122 98 89 116 122 81 *9 65 53 11.1 2 0 .0
203.01 19 168 66 20.1 98.5 2.71 197110 n o 65 69 69 65 73 69 61 57 69 65 0 .0 0 .0 203.02 18 169 53 17.9 105.1 2.92 183 98 89 69 65 65 69 65 65 69 53 37 61 0 .0 0 .0 203.03 19 169 56 1 8.6 89.8 3.16 198 • • •• • • . • m « • • 0 .0 0 .0 203 .0 6 IT 163 69 12.0 96.3 2.96 185 116 116 65 69 61 6‘5 85 96 61 65 69 69 0 .0 0 .0 203.05 20161 50 19.0 92.3 2.57 203 110 98 73 73 69 69 81 77 69 61 61 65 0 .0 0 .0 203.06 21 163 53 1 6 .5 8 6 .6 3 .03 197 138 130 89 96 69 69 102 77 73 65 61 53 0 .0 0 .0 203.07 19 163 52 2 1 .7 8 0 .22.71 176 • * • • « • • • • m •• 0 .0 0 .0 203.08 21 170 53 17.0 96.6 3.28 190 102 116 65 65 65 65 89 96 65 65 69 69 2 5 .0 2 5 .0 203.09 19 168 69 16.1 85.1 2 .72 195 126 110 85 81 61 57 81 81 65 65 53 57 0*0 0 .0 203.10 20 169 56 2 0 .0 107.3 3.06 168 122 116 89 98 69 69 85 69 73 65 61 57 0 .0 0 .0 203.11 19 173 59 18.6 8 9 .3 2 .8 3 172 162 118 102 98 69 69 98 85 69 65 53 65 75.0 7 5 .0 203.12 20 170 52 18.1 9 1 .7 2.81 206 102 118 73 Bl 53 57 89 81 57 57 65 65 0 .0 0 .0 1C2 RAH DATA SUBJECTS BY TEAM EXTN(6j>l EjjENUJOl EHN.ETO. f p i . f . E ^ N .1 8 0 . ^fcXN 206.01 19168 5 27.8 6 8 .2 2 .7 0 180 166 136 96 89 65 61 106 85 65 65 53 69 0 .0 0 .0 206.02 20 168 6 2 1 .0 8 7 .6 2.80 192 155 166 102 102 69 65 106 98 77 69 57 65 9 .1 2 5 .0 206.03 19 160 3 3 0 .0 B0.2 2 .5 0 192 122 106 81 73 53 53 73 81 69 53 61 61 0 .0 0 .0 206.06 20 157 8 1 8 .8 7 9 .8 2.21 206 155 151 102 98 57 61 89 102 65 77 65 57 0 .0 0 .0 206.05 18 155 5 16.7 8 7 .7 2 .6 6 206 n o 106 73 73 69 69 77 69 53 69 37 61 0 .0 0 .0 206 .0 6 19 173 9 2 1 .7 1 0 1 .9 2.96 210 162 122 89 77 61 57 96 85 65 61 53 69 0 .0 0 .0 2 0 6 .OT 18165 5 20.7 1 0 2 .9 2 .9 6 198 130 122 85 89 65 65 96 85 6965 53 69 0 .0 0 .0 206.08 22 175 1 26.1 9 5 .7 2 .9 6 176 187 187 130 136 102 98 122 110 89 77 69 65 9 .1 2 5 .0 206.09 18 163 1 2 3 .6 82.2 2.96. 206 136 130 89 85 65 61 102 102 77 73 57 57 0 .0 0 .0 206.10 20 163 9 1 5 .8 9 5 .9 2 .85 • 98 96 73 69 53 65 61 61 69 65 61 37 9 .1 0 .0 206.11 20 165 3 2 2 .9 77.1 3.13 180 155 163 106 102 69 73 89 102 65 69 69 53 0 .0 0 .0 206.12 19 157 6 1 8 .7 81.0 2.63 210 89 102 57 69 61 65 77 73 57 53 65 65 9 .1 0 .0 206.13 18 173 3 2 3 .3 7 5 .6 2.TI 180 116 102 77 65 53 65 65 69 69 53 61 61 0 .0 0 .0 206.16 20 166 6 1 7.3 • • • 155 151 106 102 73 73 102 106 77 77 61 61 9.1 0 .0 206.15 19 165 1 2 3 .5 86.8 2.61 206 122 116 81 31 53 57 61 69 53 69 61 37 0 .0 0 .0 206.16 18 178 3 2 5 .7 8 7 .7 2 .90 210 155 166 102 102 69 69 102 106 73 73 57 61 27-3 0 .0 206.17 19170 3 1 1 .6 9 5 .5 3.55 198 162 138 102 96 69 65 98 98 69 65 69 53 0 .0 0 .0 2 0 6 .IB 20 173 0 2 0.7 8 3 .6 2 .2 3 186 138 138 98 98 65 69 98 89 73 69 53 53 0 .0 0 .0 206.19 18161 9 23.8 8 2 .9 2 .5 6 186 110 118 69 77 69 53 85 69 61 53 65 61 9 .1 2 5 .0 206.20 19 171 1. 25.1 8 8 .2 3 .16 176 159 159 110 102 69 69 110 102 77 73 65 57 0 .0 0 .0 206.21 20 170 8 2 2 .7 100.2 3 .1 7 180 171 151 122 102 89 73 122 118 85 89 69 73 9 .1 0 .0 206.22 22 169 61 100.5 3.13 192 166 136 102 n o 77 81 77 77 69 69 53 53 9 .1 2 5 .0 EOT RAH DATA OF SUBJECTS BY TEAR EXTNI2701 FJ^XN(60J FJ^XNlljjOl FJjXNI270l IDNUN ACE HI 800YUI PEIFAT VENTLN V02LI7 hr EsTN,r ERxTN,ir i R L TINJFREQ L1NJFREG 209.01 19 160 63 2 0 .4 . . . 151 151 n o 110 73 77 98 85 69 65 57 49 3 6.4 1 6 .7 209.02 19 160 51 1 0 .9 . 155 146 98 89 65 61 94 85 73 69 53 53 18.2 1 6.7 209.03 20170 59 11.9 . . . 130 146 89 102 65 73 85 85 65 65 53 49 0 .0 0 .0 209.04 18 164 57 1 6 .9 . . . 126 126 69 89 61 57 81 81 61 61 49 45 9 .1 16.7 209.05 18 157 61 16.8 . . . 146 159 98 102 65 69 89 89 65 61 49 53 9 .1 16.7 209.06 19 160 56 1 5 .4 . . • •• •• •« « • ••• • 0 .0 0 .0 209.07 21 170 55 10.1 . . . 142 146 94 98 65 69 85 85 65 69 57 61 9 .1 1 6.7 209.08 20 163 66 1 9 .5 . 167 167 114 114 81 73 89 94 65 73 57 53 18.2 1 6.7 209.09 18 168 56 1 4 .2 . . . 122 130 89 94 69 69 85 89 65 69 49 53 0 .0 0 .0 217.01 18 164 56 1 1 .3 . . . 187 175 122 122 98 85 114 110 89 81 73 65 0 .0 0 .0 217.02 20 168 48 1 6 .0 m m ■ • •• m * •• • - * 0 .0 0 .0 217.03 18 173 68 2 0 .8 . 171 159 114 114 81 81 98 106 73 77 61 57 1 6.7 2 0 .0 217.04 21 178 70 2 0 .4 . 167 220 130 130 85 89 122 146 89 102 65 81 16.7 2 0 .0 217.05 18 175 66 1 9 .4 * * • • ••• • *« • m « 0 .0 0 .0 217 .0 6 19 168 64 1 8.9 . 187 163 122 118 81 77 106 94 73 57 53 45 16.7 2 0 .0 217.07 22 170 60 15.9 • * « •• •• • m ••• • 0 .0 0 .0 217.08 20 163 49 1 4.9 m • • •• •* • m •* •• 0 .0 0 .0 217.08 18164 48 1 1.3 • » • •• * •• m • •• m 0 .0 0 .0 217.09 21 165 66 2 2 .2 • • . 122 146 85 102 61 65 85 94 73 69 57 53 0 .0 0 .0 217.10 18 168 57 17.5 • • * •• 6 * • - • • •« 1 6.7 2 0 .0 217.11 20 175 74 1 2 .6 . 203 224 138 146 98 114 138 146 110 114 89 98 0 .0 0 .0 170 58 19.8 • « • *• • « - • •• 16.7 0 .0 217.12 20 104 m 16.7 2 0 .0 217.13 20 164 57 2 3 .5 • • ♦ •• • m • • •* • APPENDIX D STATISTICS 105 RESULTS OP THE CORRELATION OP BODY COMPOSITION VARIABLES WITH TOTAL INJURIES ANALYSIS OP VARIANCE TABLE B VALUES 2 SOURCE df SS MS F P r .VARIABLE ESTIMATE MODEL 13 9.6421 0,7471 3,72 .0001 .2838 INTERCEPT -3.4251 ERROR 122 24.3284 0,1992 TEAM 1 -0.6589 TOTAL 135 33.9705 3 -0.5530 4 0,3898 5 0,0039 6 -0.0612 PARTIAL SUM OP SQUARES RESULTS 7 -0.1949 8 0,0308 SOURCE df SS P 9 0.3019 10 0.0000 TEAM 8 7.2998 .0001 AGE 0.0756 AGE 1 0,9777 .0287 HT 0,0070 HT 1 0,1517 .3848 BODYWT -0,0691 BODYWT 1 0.2671 .2494 PERFAT 0.0473 PERPAT 1 0.1742 .3518 LEANWT 0.0912 LEANWT 1 0.3529 .1859 106 RESULTS OP THE CORRELATION OP BODY COMPOSITION VARIABLES WITH LOWER INJURIES ANALYSIS OP VARIANCE TABLE B VALUES 2 SOURCE df SS MS P P r VARIABLEESTIMATE MODEL 13 9,0002 0,6923 3,83 .0001 ,2897 INTERCEPT -3.5191 ERROR 122 22,0586 0,1808 TEAM 1 -0.6007 TOTAL 135 31,0588 3 -0.5387 4 0.4835 5 -0,1833 6 -0.1466 PARTIAL SUM OP SQUARES RESULTS 7 -0.1262 8 -0,1685 SOURCE df SS P 9 0.3876 10 0.0000 TEAM 8 7.1554 .0001 AGE 0.0511 AGE 1 0,4478 .1181 HT 0.0080 RT 1 0.1987 .2966 BODYWT -0,0847 BODYWT 1 0.4008 .1391 PERPAT 0,0656 PERPAT 1 0.3349 .1760 LEANWT 0.1102 LEANWT 1 0,5141 .0939 RESULTS OP THE CORRELATION OP AEROBIC CAPACITY VARIABLES WITH TOTAL INJURIES ANALYSIS OF VARIANCE TABLE B VALUES 2 SOURCE df SS MS P P r VARIABLE ESTIMATE MODEL 6 3.0976 0,5162 2,64 .0330 .3175 INTERCEPT -2.6853 ERROR 34 6,6584 0.1958 TEAM 7 -0.6824 TOTAL 40 9.7560 8 -0,3597 11 0.0000 AGE 0.1363 BODYWT -0.0063 PARTIAL SUM OP SQUARES RESULTS VENTLN 0.0068 V02LIT 0.2051 SOURCE df SS P TEAM 2 1,4408 .0358 AGE 1 0.9468 .0348 BODYWT 1 0.0723 .5473 VENTLN 1 0,1035 .4720 V02LIT 1 0,1264 .4273 RESULTS OP THE CORRELATION OP AEROBIC CAPACITY VARIABLES WITH LOWER INJURIES ANALYSIS OF VARIANCE TABLE B VALUES 2 SOURCE df SS MS F P r VARIABLEESTIMATE MODEL 4 2,0285 0,5071 3.65 .0134 .2887 INTERCEPT -3,3551 ERROR 36 4,9958 0.1387 AGE 0.1001 TOTAL 40 7,0243 BODYWT 0.0143 VENTLN 0,0054 V02LIT 0,1090 PARTIAL SUM OP SQUARES RESULTS SOURCE df SS P AGE 1 0.5138 .0623 BODYWT 1 0,5856 .0473 VENTLN 1 0.0704 .4807 V02LIT 1 0.0382 .6027 RESULTS OF THE CORRELATION OF MUSCULAR STRENGTH VARIABLES WITH LOWER INJURIES {60 DEGREES / SECOND) ANALYSIS OF VARIANCE TABLE B VALUES 2 SOURCE df SS MS F P r VARIABLE ESTIMATE MODEL 15 6.5626 0.4375 2.07 .0148 .1814 INTERCEPT -3.2956 ERROR 140 29.6104 0.2115 TEAM 1 -0,3387 TOTAL 155 36.1730 2 -0.2171 3 -0.1898 4 0.3182 5 0,1172 PARTIAL SUM OF SQUARES RESULTS 6 0.0793 7 0.0716 SOURCE df SS P 8 0.0601 9 0.6707 TEAM 10 5.2990 .0085 10 0.2794 HT 1 2.7972 .0004 11 0.0000 KEAKG 1 0.0668 .5749 HT 0.0201 KFAKG 1 0,0334 .6916 KEAKG 0,0400 KEADIF 1 0.0004 .9634 KFAKG -0,0448 KEADIF 1 0.0229 .7426 KEADIF 0,0337 KFADIF 0.2149 110 RESULTS OF THE CORRELATION OF MUSCULAR STRENGTH VARIABLES WITH LOWER INJURIES (180 DEGREES / SECOND) ANALYSIS OF VARIANCE TABLE B VALUES 2 SOURCE df SS MS F P r VARIABLE ESTIMATE MODEL 15 6.8300 0.4553 2.17 .0099 .1888 INTERCEPT -3,3070 ERROR 140 29,3430 0.2095 TEAM 1 -0.3613 TOTAL 155 36.1730 2 -0.2457 3 -0.2103 4 0.2755 5 0.0988 PARTIAL SUM OF SQUARES RESULTS 6 0.0871 7 0.0938 SOURCE df SS P 8 0.0592 9 0.6528 TEAM 10 5,1016 .0105 10 0.2652 HT 1 2.8323 .0003 11 0.0000 KEBKG 1 0,2780 .2514 HT 0.0200 KFBKG 1 0.1718 .3667 KEBKG 0.1256 KEBDIF 1 0,0018 .9257 KFEKG -0.1365 KFBDIF 1 0,0156 .7850 KEBDIF -0.0669 KFBDIF 0.2119 RESULTS OP THE CORRELATION OP MUSCULAR STRENGTH VARIABLES WITH LOWER INJURIES (270 DEGREES / SECOND) ANALYSIS OP VARIANCE TABLE B VALUES 2 SOURCE df SS MS P P r VARIABLEESTIMATE MODEL 15 6,9850 0.4656 2.23 .0078 .1931 INTERCEPT -2,9296 ERROR 140 29.1880 0.2084 TEAM 1 -0.2618 TOTAL 155 36.1730 2 -0,1964 3 -0.1749 4 0.3509 5 0,1024 PARTIAL SUM OF SQUARES RESULTS 6 0,0770 7 0,0559 SOURCE df SS P 8 0,0232 9 0.6316 TEAM 10 4.8897 .0137 10 0.2587 HT 1 2.6498 .0005 11 0.0000 KECKG 1 0.1147 .4595 HT 0.0192 KFCKG 1 0.2774 .2507 KECKG 0.1091 KECDIF 1 0,0545 .6098 KFCKG -0.2064 KPCDIF 1 0.1149 .4590 KECDIF -0,3831 KFCDIF 0,4896 RESULTS OP THE CORRELATION OP BODY COMPOSITION AND MUSCULAR STRENGTH VARIABLES WITH LOWER INJURIES AT 60 DEGREES/SECOND ANALYSIS OP VARIANCE TABLE B VALUES SOURCE df SS MS P p r2 VARIABLEESTIMATE MODEL 16 8.3120 0,5195 2.78 .0009 .2998 ERROR 104 19.4069 0,1866 INTERCEPT -4,1046 TOTAL 120 27.7190 TEAM 1 -0.7753 3 -0.6687 4 0.1920 5 -0.3121 PARTIAL SUM OF SQUARES RESULTS 6 -0.1673 7 -0,0407 SOURCE df SS P 8 —0,1276 9 0,4350 TEAM 8 6,1751 .0003 10 0,0000 AGE 1 0.3409 .1794 AGE 0.0476 HT 1 0.2062 .2955 HT 0.0082 LEANWT 1 0.6463 .0655 LEANWT 0.0144 KEAKG 1 0.0903 .4880 KEAKG 0,2886 KEADIF 1 0.0009 ,9418 KEADIF -0.0655 KEAKG 1 0.0480 ,6128 KFAKG -0.3217 KEADIF 1 0.0367 ,6580 KEADIF 0,3109 KARATIO 1 0,0416 ,6375 KARATIO 1,5933 113 RESULTS OP THE CORRELATION OP BODY COMPOSITION AND MUSCULAR STRENGTH VARIABLES WITH LOWER INJURYIES AT A COMBINATION OF SPEEDS ANALYSIS OP VARIANCE TABLE B VALUES 2 SOURCE df SS MS P p r VARIABLE ESTIMATE MODEL 17 10.6589 0.6269 3.79 .0001 .3845 ERROR 103 17.0600 0.1656 INTERCEPT -3.3387 TOTAL 110 27.7190 TEAM 1 -0.6463 3 -0.5546 4 0.4781 5 -0.2545 PARTIAL SUM OP SQUARES RESULTS 6 -0,0051 7 0.0041 SOURCE df SS P 8 -0.0659 9 .0,5001 TEAM 8 6.6243 .0801 10 0.0000 AGE 1 0.3106 .1738 AGE 0.0461 HT 1 0.3439 .1526 HT 0.0106 LEANWT 1 0.9616 .0177 LEANWT 0.0175 KEAKG 1 0.0283 .6800 KEAKG 0.0495 KEADIF 1 0.3599 .1435 KEADIF 1.2932 KEBKG 1 0.7884 .0314 KEBKG 0.6495 KEBDIF 1 0.6458 .0510 KEBDIF -1.8156 KECKG 1 1.7897 .0014 KECKG -0,9847 KECDIF 1 0.0406 .6212 KECDIF -0,4158