Correspondence to:

Objective: To assess the impact of an active school model on children’s physical activity (PA). Design: 16-month cluster randomised controlled trial. Setting: 10 elementary schools in Greater Vancouver, BC. Participants: 515 children aged 9–11 years. Intervention: Action Schools! BC (AS! BC) is an active school model that provided schools with training and resources to increase children’s PA. Schools implemented AS! BC with support from either external liaisons (liaison schools, LS; four schools) or internal champions (champion schools, CS; three schools). Outcomes were compared with usual practice (UP) schools (three schools). Main outcome measurements: PA was measured fou