title: The environment and physical activity: The influence of psychosocial, perceived and built environmental factors.
abstract: : This study sought to integrate perceived and built environmental and individual factors into the Theory of Planned Behavior (TPB) model to better understand adolescents' physical activity.
  
  
  METHODS
  Participants (n = 110) aged 12 to 17 years (M = 14.6 +/- 1.55) were recruited from two large metropolitan high schools in Auckland, New Zealand, were included in the analysis. Participants completed measures of the revised TPB and the perceived environment. Individual factors such as ethnicity and level of deprivation were also collected. Geographical Information Systems (GIS) software was used to measure the physical environment (walkability, access to physical activity facilities). Physical activity was assessed using the ActiGraph accelerometer and the Physical Activity Questionnaire for Adolescents (PAQ-A). Data from the various sources were combined to develop an integrated model integrated for statistical analysis using structural equation modeling.
  
  
  RESULTS
  The TPB model variables (intention and perceived behavioral control) explained 43% of the variance of PAQ-A. Unique and individual contributions were made by intention and PBC and home ownership of home equipment. The model explained 13% of time spent in moderate and vigorous physical activity (Actigraph). Unique and individual contribution was made by intention.
  
  
  CONCLUSIONS
  Social cognitive variables were better predictors of both subjective and objective physical activity compared to perceived environmental and built environment factors. Implications of these findings are discussed.
authors.affiliation: Clinical Trials Research Unit, School of Population Health, Faculty of Medical and Health Sciences, University of Auckland. r.maddison@ctru.auckland.ac.nz.
authors.forename: Ralph
authors.initials: R
authors.lastname: Maddison
authors.forename: Steven Vander
authors.initials: SV
authors.lastname: Hoorn
authors.forename: Yannan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Cliona Ni
authors.initials: CN
authors.lastname: Mhurchu
authors.forename: Daniel
authors.initials: D
authors.lastname: Exeter
authors.forename: Enid
authors.initials: E
authors.lastname: Dorey
authors.forename: Chris
authors.initials: C
authors.lastname: Bullen
authors.forename: Jennifer
authors.initials: J
authors.lastname: Utter
authors.forename: David
authors.initials: D
authors.lastname: Schaaf
authors.forename: Maria
authors.initials: M
authors.lastname: Turley