title: Self-efficacy partially mediates the effect of a school-based physical-activity intervention among adolescent girls.
abstract: BACKGROUND
  This study evaluated the effects of the Lifestyle Education for Activity Program (LEAP), a comprehensive school-based intervention emphasizing changes in instruction and school environment, on variables derived from social-cognitive theory (SCT) as mediators of change in physical activity among black and white adolescent girls.
  
  
  METHODS
  Twenty-four high schools paired on enrollment size, racial composition, urban, suburban, or rural location, and class structure were randomized into control (n = 12) or experimental (n = 12) groups. There were 1038 girls in the control group and 1049 girls in the experimental group. The multicomponent intervention emphasized the enhancement of self-efficacy and development of behavioral skills by using curricular activities within physical education classes and health education instruction. The primary outcomes were self-efficacy, outcome-expectancy value, goal setting, satisfaction, and physical activity.
  
  
  RESULTS
  Latent variable structural equation modeling indicated that: (1) self-efficacy and satisfaction exhibited synchronous, cross-sectional relationships with physical activity; (2) the intervention had direct effects on self-efficacy, goal setting, and physical activity; and (3) self-efficacy partially mediated the effect of intervention on physical activity.
  
  
  CONCLUSIONS
  To our knowledge, this study provides the first evidence from a randomized controlled trial that manipulation of self-efficacy results in increased physical activity among black and white adolescent girls. The results encourage the use of self-efficacy as a targeted, mediator variable in interventions designed to increase physical activity among girls.
authors.affiliation: Department of Exercise Science, University of Georgia, Athens, GA 30602-6554, USA. rdishman@coe.uga.edu
authors.forename: Rod K
authors.initials: RK
authors.lastname: Dishman
authors.forename: Robert W
authors.initials: RW
authors.lastname: Motl
authors.forename: Ruth
authors.initials: R
authors.lastname: Saunders
authors.forename: Gwen
authors.initials: G
authors.lastname: Felton
authors.forename: Dianne S
authors.initials: DS
authors.lastname: Ward
authors.forename: Marsha
authors.initials: M
authors.lastname: Dowda
authors.forename: Russell R
authors.initials: RR
authors.lastname: Pate
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D015444:Exercise / Q000523:psychology*; D005260:Female; D006801:Humans; D020377:Self Efficacy; D013022:South Carolina