title: Undeveloped green space and free-time physical activity in 11 to 13-year-old children.
abstract: BACKGROUND
  Research on the association between the physical environment and physical activity in children has focused on built and developed features or total green space. The impact of natural, undeveloped green spaces is unknown. The objective of this study was to determine whether the presence of undeveloped green spaces in the home neighborhood are associated with physical activity in 11 to 13-year-olds.
  
  
  METHODS
  This was a cross-sectional study of grade 6 to 8 urban residing Canadian students who participated in the 2009/10 Health Behaviour in School-Aged Children survey. Children self-reported the frequency they participated in physical activity in their free-time outside of school hours. Geographic Information Systems (GIS) were used to assess the proportion of land area within 1 km of participants' homes that was devoted to publicly accessible meadows (i.e., field vegetated primarily by grass and other non-woody plants) and treed areas (i.e., field vegetated primarily by trees and shrubs). Ordinal logistic regression models were used to examine the relationships between the undeveloped green space areas and free-time physical activity. Several intrapersonal, family, and neighborhood environment factors were controlled for in these regression models.
  
  
  RESULTS
  The proportion of neighborhood land covered by meadows was not associated with the physical activity outcome (p > 0.6). However, the proportion of neighborhood land covered by treed areas was independently associated with the physical activity outcome (p = 0.02). For each additional 5% increase in the proportion of neighborhood land covered by treed areas there was a corresponding 5% increase (95% confidence interval: 1-10% increase) in the relative odds of increasing free-time physical activity outside of school hours.
  
  
  CONCLUSIONS
  The physical activity levels of 11 to 13-year-old children was associated with the amount of space in their home neighborhood devoted to treed areas.
authors.affiliation: School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada, K7L 3N6. ian.janssen@queensu.ca.|Department of Public Health Sciences, Queen's University, Kingston, ON, Canada. ian.janssen@queensu.ca.
authors.forename: Ian
authors.initials: I
authors.lastname: Janssen
authors.affiliation: School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada, K7L 3N6. rosua@queensu.ca.
authors.forename: Andrei
authors.initials: A
authors.lastname: Rosu
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D002170:Canada; D002648:Child; D002652:Child Behavior; D003430:Cross-Sectional Studies; D017753:Ecosystem; D004779:Environment Design; D015444:Exercise; D005260:Female; D015438:Health Behavior; D006801:Humans; D016015:Logistic Models; D008297:Male; D006109:Poaceae; D011998:Recreation; D012111:Residence Characteristics; D014197:Trees