Physical activity in young children: the role of child care.

Young children's regular participation in physical activity is important not only to prevent excess weight gain and avoid chronic health problems but also to promote optimal physical, social, and psychological development. Given the large number of children enrolled in some form of out-of-home child care, this setting holds great potential to make important contributions to the welfare and health of young children, including the promotion of physical activity. The five articles included in this series were originally presented as a symposium at the 2008 American College of Sports Medicine Annual Meeting. Papers review the current evidence on levels of physical activity at child care, techniques for measuring physical activity in this setting, use of outdoor space for physical activity, the influence of child care environment and policies on children's activity, and child care-based physical activity intervention strategies.