Physical activity, media time, and body composition in young children

Background: It is uncertain as to whether physical activity (PA) may influence the body composition of young children. Purpose: To determine the association between PA, media time, and body composition in children age 4 to 7 y. Methods: 100 children (52 girls, 48 boys) were assessed for body-mass index (BMI), body fat, fat mass (FM), and fat-free mass using dual energy x-ray absorbtiometryp-tiometry (DXA). PA was monitored using accelerometers and media time was reported by parental proxy. Results: In general, correlations were low to moderate at best (r < 0.51), but in the expected direction. Total media time and TV were significantly associated with BMI (r = 0.51, P < 0.05) and FM (r = 0.29 to 0.30, P < 0.05) in girls. In boys, computer usage was significantly associated with FM in boys (r = 0.31, P < 0.05). Conclusion: The relatively low correlations suggest that other factors may influence the complex, multi-factorial body composition phenotype of young children.