. = :: : . :_ . . m. K ma a ’ I 'l ‘ l .‘ I ’=l‘.;~\u .. . .. .. .. . ‘ u u w.‘ ‘ I ‘. K . O .5 F a 5 J L v..’ o t 5 Fr“ .. . to ‘ ”.1,“ .‘L l. . ... 3 ‘5. - o .. '5 #1}. g « IX 0 Win . \9 o . I. .n 4 a .u .4 I Cu .5; o ‘ w ‘m 4... .l‘l '1 In". 6 .u v.51. OF!“ \H .0. I.- h ,"'1‘ ‘ .., . .-.- . t : 3129!3l I.-__.- _‘ lllllllllll §- 10347 9196 m . "‘--r---—- ——-—"l__'— pm ~— e- I This is to certify that the thesis entitled A Comparison of Electrocardiographic Measurements of Athletes and Non-Athletes at Michigan State College presented by Richard Lee Foerch f has been accepted towards fulfillment {- of the requirements for Mer degree in PMS. Educ. ; i , j ""_"1_ .4 -4_.- H.._:_-_L- _ _ v- I.“ I, —‘— y TT‘V". 1 :l J‘.’. .“‘\‘ k .4 ‘1' r... v : " w :l'. .01.. I 5 \ '._(s-; ,._. .*' ._ 'I‘ - - r I l’ 7‘0 1‘ - . a / 1 T ,. J K ‘ L I l I ‘0 . ‘ I " 1“; 7. ‘ ‘ v ’ 1 ’ u I~ \ ~" 7 ' - . ‘ ‘7 A) '5 - - ‘ / ' l I l ' ‘ '. . «.x . \e , r J I , ‘ _ I OVERDUE FINES ARE 25¢ PER DAY PER ITEM ' Return to book drop to remove this Checkout from your record. {. a '\ . -I‘\_ A COMPARISON OF ELECTROCARDIOGRAPHIC MEASUREMENTS OF ATHLETES AND NON—ATHLETES AT MICHIGAN STATE COLLEGE BY RICHARD LEROY F OERCH A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF ARTS Department of Physical Education 1951 ¢/// /:.‘2. y; ACKNOWLEDGMENTS I wish to express my sincere gratitude to Dr. Henry Montoye for his help and guidance throughout the study and in the preparation of this paper. I am also indebted to the stu— dents who gave their valuable time to make this experiment pos— sible. I am especially grateful to Dr. W. D. Collings, of the Physiology Department, for his interest and suggestions. TABLE OF CONTENTS CHAPTER . Page I. INTRODUCTION . . . . . . . . . . . 1 Statement of the Problem . . . . . . 2 Limitations . . . . . . . . . . . 3 Definitions of Terms Used . . . . . . 4 II. REVIEW OF THE LITERATURE . . . . . 7 III. METHOD OF PROCEDURE . . . . . . . l3 Instrument . . . . . . . . . . . . l3 Selection of Subjects . . . . . . . . 14 Measurement Procedure . . . . . . . 15 Statistical Methods . . . . . . . . . 16 IV. RESULTS . . . . . . . . . . . . . 17 V. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS . . . . . . . . 27 Summary . . . . . . . . . . . . 27 Conclusions . . . . . . . . . . . 28 Recommendations . . . . . . . . . Z9 BIBLIOGRAPHY..............31 iv Page APPENDICES. . . . . . . . . . . . . . . 33 Electrocardiogram Measurements of Athletes . . . . . . . . . . . . . 34 ElectrocardiOgram Measurements of Non-Athletes . . . . . . . . . . . . 35 Drawing of Actual ElectrocardiOgram Enlarged About Five Times . . . . . . . 36 LIST OF TABLES TABLE Page I. A Comparison of the Athletes and Non- Athletes in the Mean, Range and Standard Deviation . . . . . . . . . 18 II. Significance Levels for the Comparison of the Various Electrocardiographic Measurements of Athletes and Non— Athletes.............20 LIST OF FIGURES FIGURE Page 1. A Comparison of Electrocardiographic Measurements of Non—Athletes With the Various Sports . 22 2. A Comparison of Electrocardiographic Measurements of Non—Athletes With the Various Sports . . . . . . . . . 23 CHAPTER I INTRODUCTION ElectrocardiOgraphy was born with the introduction of the string galvanometer by Einthoven of Leyden in 1903. It had been known since 1856 that the contraction of the heart was accompanied by the production of differences in electric potential, for Kolliker and Muller1 at this time had demon— strated the fact in an experimental laboratory, using the heart of a frog. The electrocardiograph is one of the most valuable in— struments available for the investigation of the various abnormal heart conditions. With its help, it is now possible to study diseases of the heart with a precision which was impossible hitherto. An electrocardiogram is now taken as a matter of routine, being almost as commonplace a procedure as the 1 A. Kolliker and H. Muller, Nachweiss der negativen Schwanku_ng des Muskelstrome am Naturlich sich contrahierenden (Muskel, Verhandl. d. phys.—med. Gesellsch., zer Wurzb. 6:528, 1855), cited by J. B. Carter, Fundamentals of Electrocardio— graphic Interpretation (Baltimore: Charles C. Thomas, 1946), p. v11. Z determination of the blood pressure. Important information is given by the electrocardiOgram of the state of the conducting tissue of the heart. "The electrocardiogram is the time rec— ord of the electrical events in the heart from which informa— tion concerning the locus of origin of each beat and how the activity has spread can be obtained. "2 Not all regions of the heart are in a position where their effect upon the electro— cardiOgram is adequate to give this information. It follows, then, that damage to the heart may be present and yet the electrocardiogram be normal in configuration, and contra—wise, that relatively insignificant damage may be so situated as to lead to rather extensive alterations in the electrocardiOgram. It is believed by many authorities that the electrocardiogram is affected by exercise and that it can be used to differentiate between good and poor cardiovascular conditions, within limits. Statement of the Problem The purpose of this study was to compare the electro— cardiographic measurements of athletes and non—athletes at 2 Louis H. Katz, ElectrocardiOgraphy (Philadelphia: Lea and Febiger, 1949), p. 80. Michigan State College. The following measurements were selected for comparison: amplitude of the P wave, QRS inter- val, amplitude of the T wave, PR interval, QT interval, and amplitude of the QRS. Limitations The measurements used in this study were confined to leads 1, Z and 3. The following leads were taken on each subject, but not used in this study: AVR, AVL, AVF, VF, VL and VR. At no time in this study will the author attempt to give a medical interpretation of the findings. In choosing the subjects the author did not think in terms of body build, there- fore the grouping is heterogeneous. The number of athletes from the various sports was limited because perfect physical condition was stressed. This paper will not attempt to delin- eate the historical aspects of the electrocardiogram, for the author feels that it could not be covered adequately in a project of this type. Definitions of Terms Used In the field of electrocardiography, it is very difficult to describe and explain the various amplitudes and intervals in the electrocardiogram; therefore, there is an electrocardio- graphic nomenclature which is universally used and approved by the standardization committee of the American Heart Asso- ciation. The following are a list of the terms to be used in this study (refer to diagram, Appendix, page 36): 1. Amplitude of the P wave. The P wave is produced by the spread of the excitation wave over the auricles. 2. Amplitude of the R wave. The R wave occurs during the beginning of the electrification of the main mass of the walls of the ventricles. 3. Amplitude of the S wave. The S wave is produced during the electrification of the rest of the ventricular muscle. 4. Amplitude of the T wave. The T wave represents the repolarization of the sinus node and the action currents from the heart muscle. 5. Time of the PR interval. This interval represents the auriculo—ventricular conduction time, or the time required ‘T- for the excitation wave to travel from the sinus node through the auricular musculature to the auriculo-ventricular node, through this node, the His bundle, and down to the upper reaches of the right and left bundle branches. The interval is normally less than 0.20 seconds in duration. 6. Time of the QRS interval. This represents the duration of intraventricular conduction. It is less than 0. 10 seconds normally. 7. Time of the QT interval. This interval, according to Carter,4 is the best measure available for the duration of electrical ventricular systole. It varies primarily with the heart rate; with a rate of 45 it is 0.45 second, with a rate of 75 it is 0.35, while a rate of 120 per minute gives a QT inter- val of about 0.25 second. 8. Lead I. Standard lead taken from the left arm and the right arm. 9. Lead II. Standard lead taken from the right arm and the left leg. 3 Carter, 22. git” p. 43. Loc. Elli- 10. Lead III. Standard lead taken from the left arm and the left leg. 11. Precordial lead. Placing of the electrode on the precordium and another at a standardized location on the arm or leg to complete the circuit. CHAPTER II REVIEW OF THE LITERATURE In the past, most of the writing in electrocardiOgraphy has been too polemic to be of value to the unspecialized reader. On this account, while the author's own views on the subject are given main consideration, they are tempered with a rec0g— nition and presentation of other points of view. A great deal has been written in electrocardiOgraphy in the past ten years, however very little of this has been related to physical education. Only a brief resume of the work com- pleted will be related here. Wolfs set up electrocardiogram standards for normal young men at the University of Illinois. His results were as follows: 5 Jacob Grove Wolf, "Electrocardiogram Standards for Normal Young Men" (unpublished Master's thesis, The Univer— sity of Illinois at Urbana, 1948). Range (M 10’)6 Actual Range Found Amplitude of P wave 0.5 - 1.8 0.3 — 31 Amplitude of QRS 2.8 — 20. 8 1. 0 — 24. 1 Amplitude of T wave 1. 1 — 6. 1 0. 0 — 9. 4 P-QR interval .15 - . 20 .10 - . 22 QRS time . 04 - . 08 . 03 — . 09 Chamberlin and Hay6 found the following measurements in a study of 136 normal individuals, whose ages ranged from 20 through 30: Lead P Q R S T I Average 0.6 0.4 9. 1.6 3. 1 Range 0. 1—1.5 0.0—2.6 Z.5-18.6 0.0-7.5 1.1—6.5 11 Average 1.7 0.5 15. 6 3.0 4.2 Range 0.5—2.7 0.0—2.5 6.5—23.6 0.0—10.6 0.5—12.5 III Average 0.7 0. 5 9.3 1.5 —0.3 Range —3.5—2.5 0.0—3.6 1.5—20.5 0.0-8.5 -5.5-6.5 Chamberlin and Hay, "ElectrocardiOgram Standards," British Heart Journal, 1:105-115, 1939. 9 Another interesting study was made by Massey7 on the prediction of all—out treadmill running from electrocardiOgraphic measurements. Massey found that those individuals who par— ticipated vigorously in physical exercise had a smaller P wave, greater T wave amplitude, RST segment is elevated, PQR inter— val is increased, S wave may be eliminated and the QRS inter— val may be increased. On the whole, Massey found that athletes' tracings were clearer, larger, more regular, and the T wave is considered the electrocardiOgraphic measurement making the greatest contribution to the prediction of endurance running ability. In making a comparison of Olympic athletic candidates with normal standards for the electrocardiOgraph, Strydom8 found that swimmers tend to have longer QRS intervals than track and field athletes and that the athletes have either a shorter rest period or a longer work period. The rest period 7 Ben Henry Massey, "Prediction of All-Out Treadmill Running From ElectrocardiOgraphic Measurements" (unpublished Master's Thesis, The University of Illinois at Urbana, 1947). 8 N. B. Strydom, "A Comparison of Olympic Athletic Candidates With Normal Standards for the Electrocardiogram" (unpublished Master's Thesis, The University of Illinois at Urbana, 1948). 10 is considered to be from the end of the T wave to the end of the QRS complex, and the work period is the T wave duration. Hoogerwerf9 studied electrocardiographic measurements of athletes at the Olympic games at Amsterdam in 1928. He studied a total of 260 men and women and was able to get a representative sample from each Sport. Of the many athletes examined in this study, the only ones who had definite U waves were those who won their particular event. The author found, upon summarizing the results: The examinations at Amsterdam demonstrated that strong bradycardies with slow irritant transmission (Reiz— leitung) in the auricles were endured without any trouble. Even extrasystoles occurred extremely seldom, probably be— cause at the same time, the irritability in the other parts of the heart was equally reduced. 10 As a final summary, Hoogerwerf found that the athletes undergo the influence of a strong vagus tonus, the P waves were generally small and the T waves were generally large, and that in 10 per— cent of the electrocardiOgrams the QT interval is more or less in.— creased such as it occurs also in thrombosis of the coronary artery. 9 S. H00gerwerf, "Elektrokardiographische Untersuch— unger der Amsterdamer Olympiadekampfer,” Arbeitsyhysiologie, 2:61 (1929). 10 Ibid., p. 73. 11 11 Wolf found in his study on the effects of posture and muscular exercise on the electrocardiOgram, that the electro- cardiOgraph can record quite accurately the effects of exercise, and these results may be used to differentiate between good and poor cardiovascular conditions within limits. Statistically significant differences at the 5% level occurred between good and poor groups in the amplitude of the P wave and T wave after "all-out" treadmill run— ning at 7 m.p.h. , 8.6% grade. Significant differences at the 5% level in the same condition groups also occur in changes from lying to sitting and lying to standing in the P, R, and T wave amplitudes. These changes were an in— crease in P and S wave amplitude and a decrease in R and T wave amplitude. Changes in posture may suggest a valid method of differentiating between poor and good cardio— vascular condition. Robb,l3 in a study of 533 athletes and 250 medical stu— dents, computed K and attempted to show its relationship to sportsmen with a high degree of circulatory efficiency. With 11 J. Grove Wolf, "The Effects of Posture and Muscular Exercise on the Electrocardiogram" (a paper read before the Research Section, 56th National Convention of the American As— sociation For Health, Physical Education and Recreation, Detroit, Michigan, April 17, 1951). 12 LOC. 533. 13 Jane S. Robb, "QT and K Values in Athletes," Journal of Insurance Medicine, 29:33, December, January, February, 1350-51. 12 Bazett's formula, K x QT {- W, Robb found the following data: (1) K as well as QT is related to cycle length. (2) Those having high K values have slightly larger hearts than those with low K values. (3) The best relationship of K dura— tion is to diastolic blood pressure. (4) K derived from Bazett's formula, K s QT a m, is found to vary with cycle rather than to be evenly distributed above and below straight line having a value of 0.37 (for normal men). Cureton14 reports that low P waves, high T and R waves, and short P—R intervals are associated with endurance by ac— tual treadmill running tests. No P—R intervals greater than 0.22 seconds were found in 76 champion athletes. The R and T waves of highly-trained athletes were higher except in dis-— tance runners on restricted diets. 14 T. K. Cureton, "The Hearts of Athletes," Illinois Medical Journal, Volume 99, Number 3, March, 1951. CHAPTER III METHOD OF PROCEDURE Instrument The instrument used was the new PC—Z Cardiotron. This is a direct—writing electrocardiOgraph which produces permanent records instantaneously on an abrasion—resistant, thermosensitive paper. It incorporates such features as automatic instantaneous compensation during the switching of leads without pushing knobs or buttons, a fifteen—lead selector switch, absolute elimination of power line, automatic time marking, and an automatic pro- tection circuit for the stylus. The paper is ruled in one—millimeter squares. The re— quired speed of the paper movement is twenty—five millimeters per second. Each vertical line of the graph represents the passing of 0.04 seconds. The speed of the paper is controlled by a synchronous motor, whose speed is constant. The sensi— tivity for standard electrocardiographic records is set so that an injected voltage of one millivolt (0.001 volt) will produce a stylus deflection of one centimeter. 14 This instrmnent has been approved by the American Medical Association and is manufactured by the Electro-Physical Laboratories, Incorporated, Rye, New York. Selection of Subjects The athletes in this experiment were chosen because of their outstanding athletic ability. The author's main purpose was to obtain the electrocardiograms of ”tOp—notch" athletes who were in the peak of condition in their respective sport. By putting the primary emphasis on "toP—notch” condition, it was impossible to procure an even number of athletes from the various sports. The distribution of the athletes was as f0110ws: three boxers, two wrestlers, one swimmer, two tennis players, eight track and field, and four gymnasts. The non—athletes were selected because they have had no athletic experience in high school or college. All of the non—athletes in this experiment were normal young men as far as could be determined by the experimenter. None of the men in the non—athlete group were enrolled in an adapted sports class. 15 Measurement Procedure All measurements were taken in accordance with the recommendations of Wolff. 15 The instrument used for mea— surement was a pair of dividers as recommended by Dr. T. A. Hockman, a noted cardiologist in Lansing, Michigan. Ampli- tudes are vertical displacement measures and are recorded in millimeters. Interval measurements are recorded in hundredths of seconds determined by counting the small squares, interpo— lating where necessary. They are measured horizontally along the iso—electric line. Only three cycles (a cycle is considered from one T wave to the next T wave) were measured in each lead. In all leads the average amplitude and the average inter— val were recorded. The iso—electric line is used as the basic point for measurement, and all measurements are measured perpendicular to it. Each individual tested was asked to walk slowly or ride in an automobile when reporting for his exam— ination. He was also asked to refrain from eating, smoking, or drinking an alcoholic beverage two hours prior to the 15 Louis Wolff, ElectrocardiOgg-aphy Fundamentals and Clinical Application, Philadelphia and London: W. B. Saunders Company, 1950, p. 25. 16 examination. Upon arrival, the examinee was asked to lie quietly on a cot for a period of fifteen minutes. Statistical Methods The statistical analysis of the group results included the use of the student's "t" to determine the significance of the differences between these two groups. Also computed in this study was the F-test, which was used to determine whether or not homoscedasticity existed with regard to the various measurements in the two groups of subjects. Each amplitude and interval measurement was recorded, and a comparison of the athletes' and non—athletes' measurements were computed statistically to show the significance, if any. The mean, range and standard deviation for the athletes and non—athletes has been set down in table form. This is elucidated in Chapter IV. CHAPTER IV RESULTS The results are presented in table form on pages l8, 19. 20, 21, 22, and 23. In using the student's ”t," the author found that a num— ber of the measurements displayed a significance at either the 0.01 or the 0.05 level. The T—wave in lead one showed sig— nificance at the 0.01 level. The T wave represents the repolar- ization of the sinus node and is called the work period of the heart cycle. 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