['To determine whether perceptions of neighborhood safety and measures of neighborhood crime are independently associated within physical activity in youth.', "The study sample consisted of 14,125 youths in grades 6-10 (ages 11-15) who participated in the nationally representative cross-sectional 2009/10 Canadian Health Behaviour in School-Aged Children Survey. Participants responded to four questions about how safe their home neighborhood is and reported whether or not they accumulated at least 4h/week of physical activity in their free-time outside of school hours. Crimes against persons was assessed in 1 km radius buffers around participants' homes. Associations were assessed using logistic regression.", 'After controlling for crime and relevant confounders, the relative odds of being physically active outside of school was 0.52 (95% CI: 0.44-0.62) in youth whose perceptions of neighborhood safety were in the lowest quintile. After controlling for perceptions of safety and relevant confounders, the relative odds of being physically active outside of school was 0.75 (0.60-0.95) in youth from neighborhoods with crimes against persons scores in the highest quintile.'] Are crime and perceptions of safety in the home neighborhood independently associated with physical activity among 11-15 year olds?