Youth sport participation--a view of the issues: introduction to the special section.

Sport participation among children and youth is ubiquitous in U.S. society.

Risk and promotive factors in families, schools, and communities: a contextual model of positive youth development in adolescence.

Objective: Emerging evidence about optimal youth development highlights the importance of both reducing negative behavior and promoting positive behavior. In our study we tested a contextual model derived from positive youth-development theory by examining the association of family, school, and community risk and promotive factors, with several outcome indices of both positive and negative adolescent development.

Methods: A sample of 42305 adolescents aged 11 to 17 (51% girls) was drawn from the 2003 National Survey of Children's Health.