Population-based randomized controlled trial of a stage-targeted physical activity intervention.
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.
Marshall
Alison L
AL
The University of Queensland, School of Movement Studies, St Lucia, Australia. alisonm@hms.uq.edu.au
Bauman
Adrian E
AE
Owen
Neville
N
Booth
Michael L
ML
Crawford
David
D
Marcus
Bess H
BH
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