Background: Adolescents (11-18-year-olds) are at risk of physical inactivity. There is limited knowledge of physical activity (PA) levels among adolescents in the school setting in Hong Kong. We developed and tested a novel theoretical model of how household/family characteristics, school-level social and physical environmental factors and individual adolescent's characteristics impact on their school-based PA during and after school hours.; Methods: Cross-sectional study participants were Hong Kong adolescents attending secondary school, paired with their parent/caregiver (n = 1299 dyads). Parents survey-reported on household/family characteristics, parental PA and rules related to PA. Adolescents survey-reported on school PA-friendly policy, PA equipment at school (combined to create PA-friendly index), social support for PA from peers, athletic ability, attitude to and enjoyment of PA. Adolescents self-reported their school-based PA during school hours (physical education; recess) and after school (sports teams/classes). Objectively-measured moderate-to-vigorous PA (MVPA) was measured using accelerometers for a sub-sample of adolescents (n = 588). Generalized additive mixed models were used to estimate how household/family-level and school-level factors, and adolescents' individual characteristics were related to adolescents' school-based PA in Hong Kong, and to identify potential mediators of these associations.; Results: A complex network of potential pathways of influence on adolescents' school-based PA was identified. Overall, most of the significant effects were indirect ones. However, there were far fewer significant pathways between household/family characteristics and objectively-measured MVPA at school than there were for self-reported PA at school. In fact, there were no indirect pathways between these variables and MVPA at school. Gender disparities among pathways were identified. For example, school PA-friendly index was significantly associated with MVPA

Parents of children with autism spectrum disorders (ASD) reported higher stress than those of typically developing children. The role of child problem behaviors in the relationship between autism spectrum symptoms and parenting stress is little known. A total of 731 parents of 177 children with ASD and 554 typically developing children in primary schools (6–11 years old) completed an ASD screening survey containing measures of parenting stress and child problem behaviors. While autism spectrum symptoms were positively associated with parenting stress, the relationship was mediated by child problem behaviors. Results suggest neither the severity of autism spectrum symptoms nor knowledge of ASD diagnosis was a primary source of parenting stress. A hypothesized path model was tested using structural equation modeling. Copyright © 2018 Springer Science+Business Media, LLC, part of Springer Nature.