The relative contributions of adiposity and activity levels to physical performance in children with excess weight

Objective: This study examined predictors of physical performance, a key aspect of quality of life, in children with excess weight. Methods: Participants were 269 children aged 6–12 years with a body mass index above the 85th percentile. Children completed a standardized physical performance task capturing lower extremity strength, balance, and gait speed. Height, weight, and waist circumference were objectively measured, and daily moderate-vigorous physical activity (min/day) and sedentary time (% of day) were assessed with a 7-day accelerometer protocol. Results: Physical performance task completion averaged 15.0 (SD = 2.5) seconds. Children with higher body mass index z-scores and waist circumferences had significantly longer task completion times. The task took 1.8 additional seconds per 1.0 body mass index z-score (p <.001), and 1.2 additional seconds for every 20 cm higher waist circumference (p <.001). Daily moderate-vigorous physical activity and sedentary time were unrelated to physical performance, and did not moderate its associations with the adiposity measures. Conclusion: Among children with excess weight, physical performance declines with increasing levels of total and central adiposity. Daily activity levels do not moderate this association. Interventions that directly target weight reduction would likely yield the greatest improvement in physical performance in children with overweight or obesity.