Implementation of school based physical activity interventions: A systematic review

•We examined the state of the evidence regarding implementation in school-based physical activity intervention trials•Few studies linked implementation to child health outcomes•There was substantial variability in the measurement and reporting of implementation•Out of 22 factors influencing implementation, time was the most frequently reported•Additional research and standard definitions of implementation are required

ObjectiveImplementation science is an emerging area in physical activity (PA) research. We sought to establish the current state of the evidence related to implementation of school-based PA models to explore 1) the relationship between implementation and health outcomes, and 2) factors that influence implementation.MethodsWe searched 7 electronic databases (1995–2014) and included controlled studies of school-based PA programmes for healthy youth (6–18 y) measuring at least one physical health-related outcome. For objective 1, studies linked implementation level to student-level health outcome(s). For objective 2, studies reported factors associated with implementation.ResultsThere was substantial variability in how health outcomes and implementation were assessed. Few studies linked implementation and health outcomes (n = 15 interventions). Most (11/15) reported a positive relationship between implementation and at least one health outcome. Implementation factors were reported in 29 interventions. Of 22 unique categories, time was the most prevalent influencing factor followed by resource availability/quality and supportive school climate.ConclusionsImplementation evaluation supports scale-up of effective school-based PA interventions and thus population-level change. Our review serves as a call to action to 1) address the link between implementation and outcome within the school-based PA literature and 2) improve and standardize definitions and measurement of implementation.