Development and application of a moveability index to quantify possibilities for physical activity in the built environment of children.

Several studies show that urban forms are environmental correlates of physical activity. Most of these studies used data based on questionnaires while only a few used geographic information systems (GIS) to objectively assess urban forms. Based on GIS data, we applied a kernel density method to measure urban forms and combined these measures to a moveability index to assess the opportunities for physical activity in the German intervention region of the IDEFICS study. In this proof-of-principal analysis, we linked the moveability index with physical activity data obtained from the baseline survey of the IDEFICS study. Regression analyses revealed a modest but significant impact of the built environment on the physical activity of 596 school children in the study region, supporting the potential application of the moveability index.