Task Force 8: classification of sports.

This classification of sports has been developed to allow a fundamental question to be addressed: whether it is reasonably safe to recommend that an athlete with a specific cardiovascular abnormality be eligible for a particular competitive sport (1,2). We recognize that cardiovascular disease assessments are imprecise and may change over time and be influenced by exercise training. Furthermore, there are potentially life-threatening aspects to the nature of the risk involved. We have attempted to incorporate these realities into the classification system. Sports can be classified according to the type and intensity of exercise performed and also with regard to the danger of bodily injury from collision, as well as the consequences of syncope. Exercise can be divided into two broad types: dynamic (isotonic) and static (isometric) (3–6). Dynamic exercise involves changes in muscle length and joint movement with rhythmic contractions that develop a relatively small intramuscular force; static exercise involves development of a relatively large intramuscular force with little or no change in muscle length or joint movement. These two types of exercise should be thought of as the two opposite poles of a continuum, with most physical activities involving both static and dynamic components. For example, distance running has low static and high dynamic demands, water skiing has principally high static and low dynamic demands, and rowing has both high static and dynamic demands. The terms dynamic and static exercise characterize activity on the basis of the mechanical action of the muscles involved and are different from the terms aerobic and anaerobic exercise. The latter characterize activity on the basis of the type of muscle metabolism. Most high-intensity static exercise is performed anaerobically, whereas highintensity dynamic exercise lasting for more than several minutes is performed aerobically. However, some dynamic exercises, such as sprinting or jumping, are performed primarily anaerobically. Thus, many sports are placed in the high dynamic category, including such diverse activities as skiing (cross country), running (distance), soccer, and squash. Because the cardiovascular demands of very high resistance dynamic exercise are similar to sustained static exercise, those sports that have either a sustained static component or a very high resistance dynamic component are classified together as high-intensity static exercise (e.g., weightlifting, gymnastics, and field events [throwing]). The two primary factors determining the cardiovascular risk of competitive sports are, clearly, the athlete’s abnormality and the stress under which it is placed by the sport. This involves: 1) the specific cardiovascular diagnosis and its pathophysiological consequences; and 2) the cardiovascular response to the demands of the sport during both competition and training, which a competitive athlete in a sport may typically or reasonably be expected to undertake. The stress of the sport involves both static and dynamic components that determine the cardiovascular demands of the sport. Thus, for athletes with cardiovascular abnormalities, recommendations regarding eligibility for competition will recognize these factors as well as the attendant psychological stresses that invariably accompany competitive athletics. The cardiovascular demands produced by training or competition in a particular sport involve the type, intensity, and duration of the activity, with both peak intensity and total work performed as well as attendant neurohumoral effects and environmental factors.