Background: The after-school period is potentially an important venue for increasing physical activity for youth. We sought to assess the effectiveness of the Sports, Play, and Recreation for Youth (SPARK) program to increase physical activity and improve cardiorespiratory fitness and weight status among elementary students after school. Methods:…

Background: Protective factors associated with positive youth development predict health and education outcomes. This study explored trends in these protective factors and in physical activity among low-income students, and determined the impact of a school-based youth development program on these trends. Methods: This study used a…