Implementation at-scale of school-based physical activity interventions: A systematic review utilizing the RE-AIM framework

School-based interventions can increase young people’s physical activity levels, but few are implemented at-scale (i.e., the expanded delivery of efficacious interventions under real world conditions into new/broader populations). The RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) framework can be used to describe the extent to which interventions have been implemented at-scale. The aim of our review was to determine the extent to which studies of school-based physical activity interventions implemented at-scale reported information across the RE-AIM dimensions. We conducted a systematic search of seven electronic databases to identify studies published up to June 2019. A total of 26 articles (representing 14 individual studies) met the inclusion criteria and were analyzed. Eleven studies reported actual or estimated number of students exposed to the intervention, however the representativeness of these students was rarely reported. Nine studies reported the intervention effect on the primary outcome during scale-up. Ten studies reported the rate of participating schools/teachers, however none reported on the characteristics of adopters/non-adopters. Eight studies reported intervention fidelity. Eleven studies described the extent to which the intervention was sustained in schools. There was considerable variability in the reporting of RE-AIM outcomes across studies. There is a need for greater consistency in the evaluation, and reporting of, school-based physical activity interventions implemented at-scale.