Teun Remmers

Afterschool PA and the built environment using GPS, GIS and accelerometers | 139 Association between afterschool active transport and second-level built environment features Higher densities of buildings, lawns, and pedestrian paths were associated with fewer active minutes of cycling. More minutes of cycling were associated with a higher density of pedestrian area's and sports terrains. Finally, more minutes of walking were related with smaller multi-place environments and a higher density of agriculture, shrubs, main roads, and pedestrian paths. Discussion This study examined relationships between features of the built environment, children's afterschool leisure time PA behaviour and afterschool active transport. Our first, more methodological aim, was to investigate context-specific afterschool leisure time and active transport by filtering these contexts from other afterschool contexts, such as organized sports participation. This may be important since previous studies suggested that this may be a confounding factor in the relationship between PA and the built environment (29, 52). We showed that GPS devices provide additional descriptive information about the context of daily PA and mobility patterns, which enables more context-specific analyses of the relations between leisure PA and its environmental determinants (3). This study showed that greenery density (i.e. lawns and shrubs) was associated with more afterschool leisure time PA and walking, but we found no association with the density of general vegetation. Systematic reviews including studies until 2010, reported a mixed association between environmental greenspaces and PA (53, 54). However, studies from 2010 onwards using objective PA and GPS-determined environmental exposure consistently suggest that children are more active in greenspace environments such as parks (22, 32, 55, 56). Findings from the present study not only support the suggestion that shrubs and lawns (often found in parks) may be important facilitators for children’s PA, but also show that children with a higher density of shrubs and lawns in their multi- place environment, generally perform more afterschool leisure time PA than children with a lower density of these environments (irrespective of whether PA is actually performed around shrubs or lawns). In our view, this may be an important step forward in understanding relationships between greenspace environments and context-specific PA. From the six studies that investigated relationships between objective afterschool PA and the built environment (16, 19, 22-25), two studies focused on publically accessible features of the environment (19, 23). These studies suggest that not the public open space closest to children's residence is associated with afterschool PA, but also the larger home-school environment or parts thereof. In contrast to the study of Remmers et al. (2016), we found no evidence that higher density of publically accessible playgrounds was associated with more leisure time PA or active transport (23). This may be explained by the fact that GIS data did not enable us to look at quality, maintenance status, or age- appropriateness of these playgrounds. Although this study demonstrated that GIS-data can be used to assess relationships with domain-specific afterschool PA, the quality of GIS