Background
Establishing positive physical activity behaviours early in life is vital for young children’s health and development [Outside of the home, many young children spend a considerable amount of time each week in early childhood education and care (ECEC). Internationally, approximately 25% of children aged 0 to 2 years and 90% of children aged 3 to 5 years are enrolled in formal ECEC [In line with the socio-ecological model of behaviour change, interventions that combine individual and environmental (including policy) level factors are more effective than interventions focused on single-level factors [Simply having a physical activity policy is insufficient for supporting adequate physical activity levels. An ECEC-specific physical activity policy is more likely to be effective if implemented in conjunction with effective implementation supports such as educator professional development and training [To address these needs, Play Active, a physical activity policy intervention with supporting implementation strategies, was developed. The central component of Play Active is an evidence-informed physical activity policy template containing 25 practices to support nine age-specific recommendations and two key statements which provide clear guidance on the amount of physical activity and sedentary time, including screen time, young children should do while attending ECEC [This study examined the effectiveness of the Play Active intervention on changes in educator-reported daily time provided for children to be physically active at ECEC. The uptake of the policy practices by directors and educators (implementation outcomes), and the fidelity, reach, awareness, and acceptability of Play Active (process outcomes) were also examined.