Background: Inactivity is a primary factor related to childhood obesity, yet aerobic exercise has been shown to prevent weight gain and improve fitness in adolescents. Moreover, children become less active during their summer break from school. This study compared the effects of 4 and 8 weeks of supervised summer activity versus an unsupervised summer break on metabolic function and fitness in adolescents.
Methods: Twenty-two adolescents were divided into 4-week (n=6, weight 48.1±14.9 kg, body fat 27.4±8.4%) and 8-week exercise groups (n=6, weight 43.4±10.9 kg, body fat 28.5±12.8%), that performed supervised, play-based physical activity, versus an age-matched 8 week control group that maintained their typical summer break (n=10, weight 41.7±10.0 kg, body fat 23.7±8.0%). Anthropometrics, resting energy expenditure (REE), resting heart rate (RHR) and peak aerobic capacity (VO(2peak)) were evaluated before and after the intervention (4 or 8 weeks).
Results: REE showed group differences in posttraining conditions (the 4-week group vs. the control group, 1220±169 vs. 1067±144 kcal/die, and the 8-week group vs. the control group, 1202±151 vs. 1067±144 kcal/die, P=0.047), but RHR decreased (pre-program vs. post program: 97±22 vs. 80±8 beat/min, P=0.001) and VO(2peak) significantly increased (pre-program vs. post program: 27.8±7.8 vs. 34.8±6.5 mL/kg/min, P=0.001) in the 8-week group compared to the control group.
Conclusions: Eight weeks of supervised play-based activity increased REE and VO(2peak) in adolescents with concomitant decreases in RHR. These data suggest that this novel model of exercise prescription could be considered world-wide by clinicians to improve fitness base in adolescents and help to combat the growing epidemic of childhood obesity.