One-mile run performance and cardiovascular fitness in children

Background: Endurance run tests are administered in schools to assess cardi ovascular fitness, defined in the laboratory as maximum oxygen consumption. Objective: To examine the validity of this concept, assessing the influence s of body fat and maximum values of oxygen consumption per unit time, strok e volume, heart rate, and arteriovenous oxygen difference on 1-mile (1.6-km ) run time in healthy sixth-grade boys. Study Design: Subjects were 36 boys with a mean (SD) age of 12.2 (0.5) year s. The relationship was examined between body fat content (estimated by ski nfold measurements) and maximum oxygen consumption per kilogram and cardiac variables (during maximum cycle testing) with 1-mile run velocity. Results: Body fat content and maximum oxygen consumption per kilogram (inde pendent of body fat) accounted for 31% and 28% of the variance in run veloc ity, respectively. Stroke volume was the only component of maximum oxygen c onsumption that related to run performance. Conclusions: These findings suggest that cardiovascular fitness and body fa t content contribute equally to 1-mile run time in healthy boys and togethe r account for only 60% of the variance in performance on this endurance fit ness test. Consequently, 1-mile run performance in children may not serve a s a strong indicator of cardiovascular fitness.