Influence of Neighborhood Built Environments on the Outdoor Free Play of Young Children: a Systematic, Mixed-Studies Review and Thematic Synthesis.

Urban environments shape early childhood exposures, experiences, and health behaviors, including outdoor free play, influencing the physical, cognitive, social, and emotional development of young children. We examined evidence for urban or suburban built environment influences on outdoor free play in 0-6-year-olds, considering potential differences across gender, culture, and geography. We systematically searched seven literature databases for relevant qualitative, quantitative, and mixed methods studies: of 5740 unique studies, 53 met inclusion criteria. We assessed methodological quality and thematically synthesized findings from included studies. Three broad themes, features of spaces for play, routes, and social factors intersected to influence the availability, accessibility, and acceptability of neighborhoods for young children's outdoor free play across diverse cultural and geographic contexts. Proximity to formal or informal space for play, protection from traffic, pedestrian environment, green and natural environments, and opportunity for social connection supported outdoor free play. Family and community social context influenced perceptions of and use of space; however, we did not find consistent, gendered differences in built environment correlates of outdoor free play. Across diverse contexts, playable neighborhoods for young children provided nearby space for play, engaging routes protected from traffic and facilitated frequent interaction between people, nature, and structures.