The increasing incidence of obesity in children may be attributed in part to increased sedentary behavior, such as watching television, which leads to less energy expended in physical activity. We have theorized that by middle school, many children lack the physical skills or self-confidence to participate in competitive physical activities. Thus, we hypothesized that if we provided a summer and after-school program featuring noncompetitive, outdoor activities such as gardening and adventure education, we would observe increased physical activity relative to habitual physical activities at home.
To test this hypothesis, 2 experiments were conducted. In the first, 4 children aged 12 years were evaluated while they participated in a summer recreation program for 2 hours and again while they watched a videotape. They wore a uniaxial accelerometer to assess physical movement, and we used a bicarbonate labeled with 13C tracer technique to assess energy expenditure. In a second experiment, we evaluated 8 children (aged 10-12 years) twice using uniaxial accelerometry only, once while they attended the after-school program for 2 hours and then during a similar period at home.
The first study showed that the estimated energy expenditure (kilocalories · kilograms−1· hours−1) was 60% increased during the program (mean ± SD) (2.6 ± 0.5) compared with watching a videotape (1.6 ± 0.3) (P = .02). Physical movement (accelerations per minute) also was significantly increased (3959 ± 896 vs 513 ± 182) (P = .004). In the second experiment, movement was 95% increased during the program (4578 ± 1004) compared with the behavior at home (2345 ± 746) (P = .005).
These results show that an organized, noncompetitive, leisure-time program can increase physical activity in children.