Prevention in the first place: schools a setting for action on physical inactivity.

Promoting physical activity has become a priority because of its role in preventing childhood obesity and chronic disease. Ecological approaches that recognise the interaction between individuals and the settings in which they spend their time are currently at the forefront of public health action. Schools have been identified as a key setting for health promotion. An overview of the literature addressed the promotion of physical activity in schools and showed that school-based strategies (elementary or high school) that utilised classroom-based education only did not increase physical activity levels; one notable exception was screen time interventions. Although evidence is sparse, active school models and environmental strategies (interventions that change policy and practice) appear to promote physical activity in elementary schools effectively. There is also strong evidence to support multicomponent models in high schools, particularly models that incorporate a family and community component. An emerging trend is to involve youth in the development and implementation of interventions. In the context of childhood obesity and sedentary lifestyles, modest increases in physical activity levels in school-based trials are important. School initiatives must be supported and reinforced in other community settings. Health professionals play a key role as champions in the community, based on their influence and credibility. Health professionals can lend support to school-based efforts by asking about and emphasising the importance of physical activity with patients, encouraging family-based activities, supporting local schools to adopt an "active school" approach and advocating for support to sustain evidence-based and promising physical activity models within schools.