An intriguing study has examined the relationship between physical activity and a range of variables involving urban residents' homes and neighborhoods, finding that the inside of study subjects' homes had more to do with higher physical activity levels than the sidewalks, lighting and other elements considered.   NiCole Keith, from Indiana University-Purdue University (Indiana, USA), and colleagues assessed data collected on 998 African Americans, ages 49 to 65 years, enrolled in the African American Health longitudinal study.  The study used a combination of self-assessments and objective assessments to gauge study participants' perceptions of their neighborhood and residences, and researchers rated the interior and exterior of the dwellings and immediate vicinity, including such things as cleanliness, furnishings, noise, air quality and conditions of the dwelling and those of nearby buildings. The team used the Yale Physical Activity Scale to assess physical activity, adjusting for assessment data and other confounding variables.  Commenting that:  "At the end of the day, the interior condition of their house seemed to be the only thing affecting their physical activity," the team encourages efforts to increase physical activity rates in the everyday setting, and that improving the exterior, built environment may be of secondary consideration.