This report discusses the various benefits of physical activity for youth development, including positive social relationships and physiological benefits. It also outlines the importance of school and families in youth healthy living and provides tables and charts as visual aids. Maureen R. Weiss, Ph.D. and Diane M. Wiese-Bjornstal, Ph.D., President's Council on Physical Fitness and Sports Research Digest, Series 10, No.3, September, 2009