Environmental and behavioral influences of physical activity in junior high school students

Background: Increasing access and opportunity for physical activity (PA) in schools are effective; however, not everyone experiences the same effects. Prompting and reinforcement may encourage more frequent participation in recreational PA during the school day. The purpose of this study was to investigate a lunchtime PA intervention on whole school PA participation and whether behavioral support enhanced these effects. Methods: A modified reversal design compared an environmental and an environmental plus behavioral support intervention on lunchtime PA participation versus baseline levels in a suburban junior high school in the western United States (N = 1452). PA and related contextual data were collected using systematic observation. Results: Significantly more girls and boys were observed in PA during the interventions compared with baseline phases (F_2,1173 = 13.52, P < .0001, η² = .023; F_2,1173 = 20.14, P < .0001, η² = .033, for girls and boys, respectively). There were no significant differences between the environmental phase and the environment plus behavioral support phase. Conclusion: Providing access and opportunity significantly increased the number of girls and boys observed in PA during a lunchtime program, with no additive effects of behavioral support. Further research into providing the individual-level contingencies at an institutional level is needed.