Tracking physical fitness and physical activity from childhood to adolescence: the muscatine study.

PURPOSE Physical fitness and physical activity tracking data enhance our understanding as to when children settle into their long-term exercise and fitness patterns and, therefore. provide insight as to when programs focusing on preventing sedentary adults behaviors should be initiated. METHODS In this paper, the tracking of physical fitness and physical activity was examined in a 5-yr population-based study of children and adolescents in Muscatine, IA. Study subjects (N = 126) were pre- or early-pubescent at baseline (mean age boys 10.8 yr and girls 10.3 yr). Physical fitness was measured using direct determination of oxygen uptake and maximal voluntary isometric contraction while physical activity was assessed via questionnaire. RESULTS Boys classified as sedentary based on initial measurements of TV viewing and video game playing were 2.2 times more likely than their peers to also be classified as sedentary at follow-up. Tracking of most physical fitness and physical activity variables was moderate to high, indicating some predictability of early measurements for later values. Sedentary behavior tracked better in boys, whereas vigorous activity tended to track better in girls. CONCLUSION These observations suggest that preventive efforts focused on maintaining physical fitness and physical activity through puberty will have favorable health benefits in later years.