LAUSR

Center-based early childhood education and care (ECEC) programs are well-positioned to create positive impacts on the health and development of large numbers of young children by promoting physical activity using evidence-based programs. Studies testing physical activity programs for young children should examine the circumstances under which programs are most effective by assessing the role of contextual factors on program outcomes. The purpose of this study was to examine the moderating effects of baseline ECEC center characteristics on the relationship between the Study of Health and Activity in Preschool Environments (SHAPES) intervention and moderate-to-vigorous physical activity (MVPA). MVPA was assessed via accelerometry; center characteristics, practices, and social and physical environments were assessed by director interview and observation; and center quality was assessed using the Early Childhood Environment Rating Scale-Revised Edition. Mixed-model analyses of covariance (ANCOVAs) examined intervention effects on MVPA during the school day; interactions between baseline center variables and group assignment (intervention vs. control) tested for moderation. Two center instructional practices, two social environment characteristics, and one physical environment characteristic at baseline moderated the effects of SHAPES on MVPA outcomes. Assessing baseline practices and center characteristics may aid efforts to match centers with interventions likely to increase physical activity as well as suggest additional intervention strategies to test.