title: Healthy for life: a randomized trial examining physical activity outcomes and psychosocial mediators.
abstract: BACKGROUND
  Researchers theorize that interventions increase physical activity by influencing key theory-based mediators (e.g., behavioral processes). However, few studies have been adequately powered to examine the importance of mediators.
  
  
  OBJECTIVE
  This study examined both physical activity behavior and psychosocial mediators in a randomized trial specifically powered to detect mediation.
  
  
  METHODS
  Healthy, sedentary adults (n = 448; 70 % Caucasian, 87 % women, mean age was 43) were randomly assigned to either a 6-month print-based theory tailored physical activity intervention (n = 224) or a 6-month health/wellness contact control arm (n = 224).
  
  
  RESULTS
  The print intervention arm exhibited greater increases in physical activity than the control arm at 6 and 12 months (p < .05). Additionally, behavioral processes were found to be an important mediator of physical activity behavior.
  
  
  CONCLUSIONS
  It is important for researchers and practitioners to focus on increasing behavioral strategies for physical activity adoption. Future studies should examine other potential mediators of physical activity.
authors.affiliation: University of Minnesota, 1900 University Ave SE, Cooke Hall, Minneapolis, MN 55455, USA. blewis@umn.edu
authors.forename: Beth A
authors.initials: BA
authors.lastname: Lewis
authors.forename: David M
authors.initials: DM
authors.lastname: Williams
authors.forename: Brian C
authors.initials: BC
authors.lastname: Martinson
authors.forename: Shira
authors.initials: S
authors.lastname: Dunsiger
authors.forename: Bess H
authors.initials: BH
authors.lastname: Marcus
mesh_terms: D000328:Adult; D015444:Exercise / Q000523:psychology*; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006293:Health Promotion; D006801:Humans; D008297:Male; D009043:Motor Activity; D057185:Sedentary Behavior; D020377:Self Efficacy