Physical activity during young childhood is related to favorable levels of positive health outcomes such as cardiovascular disease risk factors (e.g., blood lipids, blood pressure) , body composition , motor skill development , and psychosocial characteristics . Current U.S. recommendations are for preschool children to obtain at least 15 minutes per hour of at least light intensity physical activity while they are in childcare . Inadequate proportions of preschool children in the U.S. , Australia , and other countries  are meeting either the prior or current recommendations. Thus, several researchers have noted the importance of interventions to increase physical activity during the preschool years [9, 10], specifically citing preschools as important settings .
Over half of young children (3-5 year olds not in kindergarten) in the U.S. spend time in center-based preschool settings . Researchers have shown that preschools are related to young children’s physical activity [12–14], indicating the importance for addressing physical inactivity in those settings. Preschools are complex settings because children spend time in different locations (indoors versus outdoors) and different contexts within those locations, such as circle/group time or pre-academic learning time when indoors versus open space or fixed equipment when outdoors. Specific preschool characteristics that have been associated with children’s physical activity include program quality , environmental variables (e.g., portable equipment, larger playgrounds) , and social variables (e.g., teacher arranged activities while indoors, child-initiated activities while outdoors) . Effective physical activity interventions in preschools need to account for these variations in setting characteristics.
Although researchers have identified physical activity-promoting characteristics in preschools, there have been relatively few preschool physical activity intervention studies thus far [9, 17], particularly randomized controlled trials [9, 10]. Existing randomized controlled trials have shown ability to increase physical activity within the preschool setting [18–22]; however, these studies were conducted in different countries or specific cultural groups, were relatively short in duration, or were implemented primarily by well-trained interventionists and not children’s teachers. To address the low prevalence of meeting physical activity recommendations and lack of evidence regarding physical activity interventions in preschool children in the U.S., we designed the Study of Health and Activity in Preschool Environments (SHAPES) using known activity-promoting characteristics. SHAPES is a randomized trial designed to increase physical activity within preschool settings.
The aims of SHAPES were to (a) observe the effects of a multi-component intervention on physical activity, sedentary behavior, and physical activity energy expenditure in 3-5 year-old children; (b) identify factors that associate with change in physical activity, sedentary behavior, and physical activity energy expenditure during a school year in preschool children; and (c) evaluate the process of implementing a multi-component preschool intervention to increase physical activity and reduce sedentary behavior in 3-5 year-old children. SHAPES interventionists employed a flexible and adaptive approach to incorporating physical activity opportunities throughout the entire preschool day. Interventionists worked with teachers (e.g., workshops, on-site consultations) to develop and adapt their own daily activities to their specific classrooms. The goal was to maximize physical activity opportunities throughout the preschool day including outdoor play and classroom activities (e.g., center time, large group activities, pre-academic lessons). The purpose of this manuscript is to describe the SHAPES study design and intervention protocol.