title: Stages of change in adolescents: an examination of self-efficacy, decisional balance, and reasons for relapse.
abstract: OBJECTIVE
  The purpose of this study was to test selected constructs of the transtheoretical model (TTM) of behavior change in relation to exercise behavior with an adolescent sample. A further purpose was to examine reasons why adolescents stop physical activity and to relate these to stages of exercise change.
  
  
  METHODS
  Participants were 15 to 17 year old students at a private high school (N = 327). Participants completed a questionnaire consisting of an exercise measure, measures of the TTM variables, and an open-ended question that asked if they used to exercise in the past but currently did not, why they had stopped. The TTM data were analyzed using ANOVA F-tests with post-hoc Scheffe tests. To evaluate the ability of the TTM variables to discriminate between stages of exercise behavior, standard discriminant function analyses were performed. Open-ended answers to the relapse question were themed according to a model which categorizes barriers preventing youth's participation in recreational activities as infrastructural, superstructural, and procedural. The relationship of perceived barriers to stage of behavior change was assessed using cross-tabulation and chi-square analyses.
  
  
  RESULTS
  Moderate support for the TTM constructs were found, with the strongest discriminator between stages being strenuous exercise, and self-efficacy being the most supported construct. Infrastructural, superstructural, and procedural barriers were all evident.
  
  
  CONCLUSIONS
  Over 30% of previously active adolescents in this study reported barriers precluding extracurricular physical activity. Interventions should target the most often cited reasons for relapse: time and limits relating to the nature of the adolescent self.
authors.affiliation: Department of Kinesiology and Physical Education, Wilfrid Laurier University, Canada. tberry@wlu.ca
authors.forename: Tanya
authors.initials: T
authors.lastname: Berry
authors.forename: P J
authors.initials: PJ
authors.lastname: Naylor
authors.forename: Joan
authors.initials: J
authors.lastname: Wharf-Higgins
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D003657:Decision Making; D015444:Exercise; D005260:Female; D015438:Health Behavior; D006306:Health Surveys; D006801:Humans; D008297:Male; D008960:Models, Psychological; D009042:Motivation; D020377:Self Efficacy