title: A multi-level examination of school programs, policies and resources associated with physical activity among elementary school youth in the PLAY-ON study.
abstract: BACKGROUND
  Given the decline in physical activity (PA) levels among youth populations it is vital to understand the factors that are associated with PA in order to inform the development of new prevention programs. Many studies have examined individual characteristics associated with PA among youth yet few have studied the relationship between the school environment and PA despite knowing that there is variability in student PA levels across schools.
  
  
  METHODS
  Using multi-level logistic regression analyses we explored the school- and student-level characteristics associated with PA using data from 2,379 grade 5 to 8 students attending 30 elementary schools in Ontario, Canada as part of the PLAY-Ontario study.
  
  
  RESULTS
  Findings indicate that there was significant between-school random variation for being moderately and highly active; school-level differences accounted for 4.8% of the variability in the odds of being moderately active and 7.3% of the variability in the odds of being highly active. Students were more likely to be moderately active if they attended a school that used PA as a reward and not as discipline, and students were more likely to be highly active if they attended a school with established community partnerships. Important student characteristics included screen time sedentary behaviour, participating in team sports, and having active friends.
  
  
  CONCLUSIONS
  Future research should evaluate if the optimal population level impact for school-based PA promotion programming might be achieved most economically if intervention selectively targeted the schools that are putting students at the greatest risk for inactivity.
authors.affiliation: Department of Population Studies and Surveillance, Cancer Care Ontario, Toronto, Ontario, Canada. scott.leatherdale@cancercare.on.ca
authors.forename: Scott T
authors.initials: ST
authors.lastname: Leatherdale
authors.forename: Steve
authors.initials: S
authors.lastname: Manske
authors.forename: Guy
authors.initials: G
authors.lastname: Faulkner
authors.forename: Kelly
authors.initials: K
authors.lastname: Arbour
authors.forename: Chad
authors.initials: C
authors.lastname: Bredin