Intervention Effects on Adolescent Physical Activity in the Multicomponent Space Study – A Cluster Randomised Controlled Trial

Background: Multicomponent school-based interventions have the potential to reduce the age-related decline in adolescents‘ physical activity (PA). Studies on the effect of school environment interventions have reported varying results.

Purpose: To assess the effectiveness of a multicomponent environmental school-based intervention, designed to reduce the age-related decline in PA among adolescents.

Methods: A cluster randomised controlled trial was conducted with 7 intervention and 7 control schools in the Region of Southern Denmark. Baseline measurements were carried out in 2010 with 2 years of follow-up. A total of 1,348 students (11-13 years, in grade 5-6) enrolled in the study at baseline. The intervention consisted of organisational and physical changes in the school environment with a total of 11 intervention components. Total PA and PA in school and during recess were measured using Actigraph GT3X.

Results: 797 students completed the trial and had valid accelerometer data. No significant difference was found for overall PA with an adjusted difference of -19.1 cpm (95% CI: -93, 53) or for school time activity 6 cpm (95% CI: -73, 85). A sensitivity analysis revealed a significant intervention effect of PA in recess with an adjusted difference of 95 cpm.

Conclusions: No evidence was found of the overall effect of a non-curricular multicomponent school-based intervention on PA among Danish adolescents. The intervention was positively associated with PA during school time and recess, however, with small estimates. Lack of effect on overall PA could be due to both program theory and different degrees of implementation.