title: Population-based randomized controlled trial of a stage-targeted physical activity intervention.
abstract: BACKGROUND
  Intervention trials with self-selected participants have shown that mailed stage-targeted print materials can increase participation in physical activity in the short term. We examined the effects of a mailed stage-targeted print intervention designed to promote physical activity, in a random sample of adults living in a regional city.
  
  
  METHODS
  Participants (n = 462, 40-60 years of age) were randomly allocated to an intervention (n = 227) or control group (n = 235). Measures included validated 2-week physical activity recall and stage of motivational readiness for physical activity. The intervention consisted of a single mailing of a letter and full-color stage-targeted booklets (specific to precontemplation, contemplation, preparation, and action/maintenance) 1 week postbaseline. Follow-up interviews were conducted at 2 and 6 months postbaseline.
  
  
  RESULTS
  After 2 months, participants in the intervention group were significantly more likely to meet the current American College of Sports Medicine/Centers for Disease Control and Prevention recommendation for sufficient physical activity than those in the control group (adjusted odds ratio [OR] = 2.40; 95% confidence interval [CI] = 1.44-3.99). After 6 months, intervention participants who reported receiving and reading the intervention materials were significantly more likely to be meeting the sufficient physical activity criterion compared with the control group (adjusted OR = 2.03; 95% CI = 1.16-3.56).
  
  
  CONCLUSIONS
  The stage-targeted print intervention was effective in promoting short-term increases in physical activity and was most effective for participants who recognized and used the materials. This low-cost, generalizable intervention has demonstrated potential as a practical population-based physical activity promotion strategy. Further research is required before widespread dissemination would be justified, as additional strategies may be required to ensure sustained change.
authors.affiliation: The University of Queensland, School of Movement Studies, St Lucia, Australia. alisonm@hms.uq.edu.au
authors.forename: Alison L
authors.initials: AL
authors.lastname: Marshall
authors.forename: Adrian E
authors.initials: AE
authors.lastname: Bauman
authors.forename: Neville
authors.initials: N
authors.lastname: Owen
authors.forename: Michael L
authors.initials: ML
authors.lastname: Booth
authors.forename: David
authors.initials: D
authors.lastname: Crawford
authors.forename: Bess H
authors.initials: BH
authors.lastname: Marcus
mesh_terms: D000328:Adult; D015992:Body Mass Index; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011159:Population Surveillance; D013997:Time Factors