title: Physical activity opportunities associated with fitness and weight status among adolescents in low-income communities.
abstract: OBJECTIVE
  To identify physical activity opportunities linked to fitness and weight status among adolescents in low-income communities.
  
  
  METHODS
  Cross-sectional, ecological analysis of 9268 seventh- and ninth-grade students in 19 public schools participating in The California Endowment's Healthy Eating Active Communities program.
  
  
  METHODS
  Cardiorespiratory fitness (mile time) and body mass index. Independent variables included students' perceptions and behaviors related to daily physical activity opportunities, assessed via anonymous survey. Ecological analysis was used to link survey data with fitness and body mass index data within each school. Linear regression identified associations between youths' perceptions/behaviors and fitness/body mass index.
  
  
  RESULTS
  As the proportion of students reporting enjoying physical education, walking to school, and spending 20 minutes or longer in exercise during physical education increased from 0% to 100%, mile time decreased overall (-2.7 minutes; P = .03), mile time decreased among seventh graders (-3.3 minutes; P = .02), and body mass index z scores decreased among ninth graders (-0.7; P = .045), respectively. Each additional day students reported being active on school grounds outside school hours was associated with decreased mile time (-0.5 minute; P = .02). Active transport to school was associated with poorer weight status and greater odds of purchasing food while in transit (odds ratio = 1.5; P < .001).
  
  
  CONCLUSIONS
  Physical education is a valuable policy opportunity to improve student health. Promoting active transport may improve fitness but must be done in conjunction with community partnerships to improve the food environment in the vicinity of schools. Promoting the use of school grounds outside school hours (such as after-school programs) should also be prioritized in response to youth obesity.
authors.affiliation: Department of Pediatrics, University of California, San Francisco, San Francisco, CA 94118, USA. madsenk@peds.ucsf.edu
authors.forename: Kristine A
authors.initials: KA
authors.lastname: Madsen
authors.forename: Wendi
authors.initials: W
authors.lastname: Gosliner
authors.forename: Gail
authors.initials: G
authors.lastname: Woodward-Lopez
authors.forename: Patricia B
authors.initials: PB
authors.lastname: Crawford
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D001835:Body Weight; D002140:California; D002320:Cardiovascular Physiological Phenomena; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D015438:Health Behavior; D006801:Humans; D007182:Income; D016014:Linear Models; D008297:Male; D010809:Physical Fitness; D012143:Respiratory Physiological Phenomena; D013334:Students