title: Perceived physical environment and physical activity across one year among adolescent girls: self-efficacy as a possible mediator?
abstract: OBJECTIVE
  This study involved an examination of the direct and mediated effects of perceived equipment accessibility and neighborhood safety on physical activity across a one-year period among adolescent girls.
  
  
  METHODS
  Adolescent girls (N = 1,038) completed self-report measures of perceived environment, barriers self-efficacy, and physical activity in the Spring semesters of 1999 (baseline) and 2000 (follow-up) when students were in the 8th and 9th grades.
  
  
  RESULTS
  An initial analysis demonstrated that neighborhood safety did not exhibit cross-sectional or longitudinal direct effects on physical activity, whereas equipment accessibility exhibited a statistically significant cross-sectional, but not longitudinal, direct effect on physical activity. The secondary analysis demonstrated that self-efficacy for overcoming barriers mediated the cross-sectional effect of equipment accessibility on physical activity.
  
  
  CONCLUSIONS
  We conclude that the cross-sectional effect of perceived equipment accessibility on physical activity is mediated by self-efficacy for overcoming barriers among adolescent girls. This is consistent with the reciprocal relationships among the environment, person, and behavior described by social-cognitive theory.
authors.affiliation: Department of Kinesiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3895, USA. robmotl@uiuc.edu
authors.forename: Robert W
authors.initials: RW
authors.lastname: Motl
authors.forename: Rod K
authors.initials: RK
authors.lastname: Dishman
authors.forename: Dianne S
authors.initials: DS
authors.lastname: Ward
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Saunders
authors.forename: Marsha
authors.initials: M
authors.lastname: Dowda
authors.forename: Gwen
authors.initials: G
authors.lastname: Felton
authors.forename: Russell R
authors.initials: RR
authors.lastname: Pate
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D004777:Environment; D015444:Exercise; D005260:Female; D006801:Humans; D010465:Perception; D012111:Residence Characteristics; D012449:Safety; D020377:Self Efficacy