School-based physical activity interventions for children and youth: Keys for success

Given the rising trend in obesity in children and youth and age-related decline in moderate-to- vigorous-intensity physical activity (MVPA) in several Western, African, and Asian-Pacific countries1 and strong evidence that past physical activity (PA) interventions have had only a small effect on children's and youth's overall activity levels,2 it is important to clarify whether school-based PA interventions warrant resource allocation.Schools represent an accessible and cost-effective setting from which to stimulate engagement in PA because an underlying link already exists within that curriculum domain, and there is the potential to directly reach all cohorts of children and youth.3 School-based PA interventions fall into 5 broad categories: physical education (PE) curriculum, classroom activity breaks, active commuting to school, modified playgrounds, and comprehensive approaches that combine these approaches.4 Previous reviews of PA1 and school-based interventions4 for children and youth highlight the following key points in order to increase the effectiveness of future efforts to promote PA behavior in the school context.