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1198 JACC Vol. 6. No.6 December 1985:1198-9 Classification of Sports JERE H. MITCHELL, MD, FACC, C. GUNNAR BLOMQVIST, MD, FACC, WILLIAM L. HASKELL, PHD, FACC, FREDERICK W. JAMES, MD, FACC, HENRY S. MILLER, JR., MD, FACC, WILLIAM W. MILLER, MD, FACC, WILLIAM B. STRONG, MD, FACC Sports may be classified according to the type and intensity of exercise performed and to the danger of body collision (l,2). A classification of sports is given in Table 1 which divides exercise into two general types: static (isometric) and dynamic (isotonic) (3,4) and categorizes the intensity of exercise into low, medium or high. It also lists those sports that pose significant danger of body collision, either because of the probability of hard impact between compet• itors or between a competitor and an object, and the further danger the athlete would be exposed to if syncope occurred. Dynamic exercise involves changes in muscle length and joint movement with rhythmic contractions which develop a relatively smaller force, whereas static exercise involves development of a relatively larger force with little or no change in muscle length or joint movement. These two types of exercise should be thought of as the two extremes of a continuum with most physical activity having both static and dynamic demands. For example, distance running, swimming and rhythmic calisthenics have principally dy• namic demands and weight lifting, water skiing and gym• nastics have principally static demands. Dynamic exercise performed with a large muscle mass causes a marked increase in oxygen consumption and car• diac output. There is an increase in systolic blood pressure; however, diastolic and mean pressures remain relatively constant and peripheral vascular resistance decreases. On the other hand, static exercise, which usually involves a much smaller muscle mass than dynamic exercise, causes a smaller increase in oxygen consumption and cardiac out• put. There is a marked increase in systolic, diastolic and mean arterial pressure; however, peripheral vascular resist• ance increases only slightly. During dynamic exercise there is an increase in stroke volume with small changes in mean arterial pressure, whereas during static exercise the stroke volume changes little with an increase in mean arterial pres• sure. Thus, dynamic exercise may be thought of as primarily © 1985 by the American College of Cardiology causing a volume load, and static exercise as producing a pressure load, on the left ventricle. Both static and dynamic exercise change several factors that are important in determining myocardial oxygen de• mand: heart rate, wall tension and contractile state of the ventricle (5,6). Wall tension is affected by pressure devel• opment and ventricular volume. In dynamic exercise, there is a large increase in heart rate and an increase in stroke volume, which is achieved both by an increase in end• diastolic volume (Frank-Starling mechanism) and a decrease in end-systolic volume (increased contractile state). In static exercise there is a smaller increase in heart rate and little change in end-diastolic and end-systolic volumes of the left ventricle. However, arterial pressure and contractile state of the ventricle are increased. Thus both dynamic and static exercise cause increases in factors that are important in determining myocardial oxygen demand. There are important limitations to the classification of sports according to the type and intensity of exercise per• formed as presented in Table 1. For example, it does not consider the emotional stress a particular athlete experiences during a specific event. Thus, although competitive golf has low dynamic and static demands, during championship com• petition the subject may be exceedingly anxious and the resulting catecholamine response cause marked increases in heart rate or arterial pressure, thereby increasing myocardial oxygen demand. In addition, the classification scheme does not take into consideration the training programs required for each of the specific sports that might require a different type and increased intensity of exercise (and thereby risk) above and beyond that of the competitive event itself. Finally, this classification may be of theoretical interest but its practical value is unknown because our current knowledge regarding the relative risks of these two types of exercise for various cardiovascular abnormalities is limited. 0735-1097/85/$3.30 MITCHELL CLASSIFICATION OF SPORTS lACC Vol. 6. No.6 December 19X5:1198-·Y 1199 Table I. Classification of Sports I. Intensity and type of exercise performed A. High to moderate intensity I. High to moderate dynamic and static demands Boxing Crew/rowing Cross-country skiing Cycling Downhill skiing Fencing football Ice hockey Rugby Running (sprint) Speed skating Water polo Wrestling 2. High to moderate dynamic and low static demands Badminton Baseball Basketball Field hockey Lacrosse Orienteering Ping-pong Race walking Racquetball Running (distance) Soccer Squash Swimming Tennis Volleyball 3. High to moderate static and low dynamic demands Archery Auto racing Diving Equestrian Field events (jumping) Table I. «('()ntinueJ) field events (throwing) Gymnastics Karate or judo Motorcycling Rodeoing Sailing Ski jumping Water skiing Weight lifting B. Low intensity (low dynamic and low static demands) Bowling Cricket Curling Golf Riflery II. Danger of body collision Auto racing* Bicycling" Boxing Dlving* Downhill skiing* Equestrian'" Football Gymnastics * Icc hockey Karate or judo l,acn)~~c Motorcycling* Polo* Rodeoing* Rugby Ski jumping* Soccer Water polo* Water skiing* Weight lifting* Wrestling *Increased risk if syncope occurs. References I. Shaffer TE. The health examination for participation in sports. Pediatr Ann 1978:7:27-40. 2. Strong WB, Alpert BS. The child with heart disease: play. recreation and sports. Curr Prob Cardiol 1981 :6: 1-38. 3. Mitchell JH, Wildenthal K. Static (isometric) exercise and the heart: physiological and clinical considerations. Annu Rev Med 1974:25:369-81. 4. Asmussen E. Similarities and dissimilarities between static and dynamic exercise. Cire Res 19~n:48(6)(suppll):3-IO. 5. Sonnenblick EH, Ross J Jr, Braunwald E. Oxygen consumption of the heart. Newer concepts of its multifactorial determination. Am J Cardiol 1968:22:328-36. 6. Mitchell JH, Hefner LL, Monroe RG. Performance of the left ventricle. Am J Med 1972:53:481-94.