title: Explaining physical activity levels from a self-efficacy perspective: the physical activity counseling trial.
abstract: BACKGROUND
  The Physical Activity Counseling (PAC) trial compared the effects of a 13-week primary care physical activity (PA) intervention that incorporated a PA counselor into a health care practice compared to a control condition on PA over a 25-week period and showed group differences in PA were present at 6 and 13 weeks.
  
  
  OBJECTIVE
  The main purpose was to examine the mediating effect of 6-week task and barrier self-efficacy on the intervention versus control group/13-week PA relationships. A secondary purpose was to determine whether task and barrier self-efficacy were significantly related to PA throughout the trial for both groups.
  
  
  METHODS
  Participants were primarily sedentary individuals who received a 2- to 4-min PA intervention from their primary care provider, after which they were randomly assigned to the intervention (n = 61) or control condition (n = 59). Self-reported PA and task (barrier) self-efficacy measures were obtained during (i.e., baseline, 6 and 13 weeks) and after (i.e., 19 and 25 weeks) the intervention in both groups.
  
  
  RESULTS
  Six-week task and barrier self-efficacy had a small mediating effect. Furthermore, barrier self-efficacy had a significant relationship with PA throughout the trial, whereas the relationship between task self-efficacy and PA became significantly weaker as the trial progressed.
  
  
  CONCLUSIONS
  PAC interventions among primarily sedentary individuals should be partly based on barrier and task self-efficacy. However, the stability of the task self-efficacy/PA relationship needs further examination.
authors.affiliation: Dalhousie University, Department of Medicine, Halifax, NS, Canada. chris.blanchard@dal.ca
authors.forename: Chris M
authors.initials: CM
authors.lastname: Blanchard
authors.forename: Michelle
authors.initials: M
authors.lastname: Fortier
authors.forename: Shane
authors.initials: S
authors.lastname: Sweet
authors.forename: Tracey
authors.initials: T
authors.lastname: O'Sullivan
authors.forename: William
authors.initials: W
authors.lastname: Hogg
authors.forename: Robert D
authors.initials: RD
authors.lastname: Reid
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Sigal
mesh_terms: D000328:Adult; D003376:Counseling; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D009043:Motor Activity; D020377:Self Efficacy; D011795:Surveys and Questionnaires