title: Observed, GIS, and self-reported environmental features and adolescent physical activity.
abstract: OBJECTIVE
  Examine associations among observed, self-reported, and Geographical Information Systems (GIS) environmental features and physical activity among adolescent males.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Boy Scout troops and neighborhoods in Houston, Texas.
  
  
  METHODS
  Two hundred and ten 10- to 14-year-old Boy Scouts.
  
  
  METHODS
  Accelerometry to obtain minutes of sedentary, light, and moderate to vigorous activity per day. GIS sources were used to identify the numbers of parks, gymnasiums, trails, bus stops, grocery stores, and restaurants within a 1-mile radius of participant residences as well as residential density, connectivity, and crime. Participants provided a self-report of their environment.
  
  
  METHODS
  Principal component analysis was used to reduce the number of GIS and self-reported items. Four factors were previously obtained from direct observations of the neighborhoods. Correlations were conducted among factors and physical activity. Regression models were run in which minutes of sedentary behavior, light, or moderate to vigorous physical activity were the dependent variables and environmental factors were the independent variables. Nonsignificant variables were removed in a backward deletion process.
  
  
  RESULTS
  Three GIS factors, Parks, Crime, and Gyms, were obtained as were two self-reported factors: difficulty and access and safety. Factor scores were interrelated and associated with the four observed factors. Only observed sidewalk characteristics were correlated with physical activity and were retained in the regression models.
  
  
  CONCLUSIONS
  Environmental factors were interrelated. Only sidewalk characteristics were associated with sedentary behavior and light intensity physical activity.
authors.affiliation: Department of Exercise and Health Sciences, Centre for Sport, Exercise and Health, University of Bristol, Tyndall Avenue, Bristol BS8 1TP, United Kingdom. russ.jago@gmail.com
authors.forename: Russell
authors.initials: R
authors.lastname: Jago
authors.forename: Tom
authors.initials: T
authors.lastname: Baranowski
authors.forename: Janice C
authors.initials: JC
authors.lastname: Baranowski
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D002648:Child; D003430:Cross-Sectional Studies; D003625:Data Collection / Q000379:methods*; D040362:Geographic Information Systems; D006801:Humans; D008297:Male; D009043:Motor Activity; D025341:Principal Component Analysis; D011998:Recreation; D012111:Residence Characteristics; D012449:Safety