Not unexpectedly, then, evidence exists that body fat content is responsible for a significant proportion of the relationship observed between distance run performance and V̇O 2max expressed per kilogram of body mass. 4Īdiposity, however, negatively influences both distance run time (by the excess "baggage" that must be transported) and V̇O 2max per kilogram (acting as a metabolically inert load in the denominator). 3 Moreover, correlations between V̇O 2max, expressed relative to body weight, and 1-mile run time in studies of children have been moderately high ( r=−0.65 to −0.75). Values of V̇O 2max indicate the functional limits of the oxygen delivery chain, critical for providing an aerobic energy source necessary for distance performance. The expectation that a child's 1-mile run time should reflect his or her V̇O 2max, as determined on laboratory exercise testing, has both a conceptual and empirical basis. According to this concept, then, children with poor cardiovascular fitness scores should be identified by inferior performance on endurance fitness tests and enrolled in remedial exercise programs. 1, 2 Early promotion of physical fitness and activity in children has been considered an optimal strategy for preventing these lifelong diseases. Studies in adult populations indicate that cardiovascular fitness and regular physical activity are associated with a lower risk for coronary artery disease, hypertension, obesity, and other chronic illnesses. This testing has been based on a strategy of promoting cardiovascular fitness for its positive health outcomes. SCHOOL-BASED physical fitness test batteries traditionally include endurance performance (such as the 1-mile run) as a field indicator of "cardiovascular fitness," defined as maximum oxygen consumption (V̇O 2max). Consequently, 1-mile run performance in children may not serve as a strong indicator of cardiovascular fitness. Stroke volume was the only component of maximum oxygen consumption that related to run performance.Ĭonclusions These findings suggest that cardiovascular fitness and body fat content contribute equally to 1-mile run time in healthy boys and together account for only 60% of the variance in performance on this endurance fitness test. Results Body fat content and maximum oxygen consumption per kilogram (independent of body fat) accounted for 31% and 28% of the variance in run velocity, respectively. The relationship was examined between body fat content (estimated by skinfold measurements) and maximum oxygen consumption per kilogram and cardiac variables (during maximum cycle testing) with 1-mile run velocity. Study Design Subjects were 36 boys with a mean (SD) age of 12.2 (0.5) years. Objective To examine the validity of this concept, assessing the influences of body fat and maximum values of oxygen consumption per unit time, stroke volume, heart rate, and arteriovenous oxygen difference on 1-mile (1.6-km) run time in healthy sixth-grade boys. Shared Decision Making and Communicationīackground Endurance run tests are administered in schools to assess cardiovascular fitness, defined in the laboratory as maximum oxygen consumption.Scientific Discovery and the Future of Medicine. ![]()
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