Components of the transtheoretical model of change were examined in a prospective study of the adoption of vigorous exercise in adults. Respondents to a random mail survey were resurveyed 2 years later. Those who reported no vigorous exercise at baseline were classified as either contemplators (n = 213) or precontemplators (n = 188). Contemplators had higher baseline self-efficacy scores than precontemplators (p < .001). In multivariate analyses, baseline stage of change was a significant predictor (p < .0005) of later adoption of vigorous exercise, even after controlling for differences in age, gender, and self-efficacy. During the first 6 months postbaseline, contemplators were nearly twice as likely as precontemplators to progress to the stage of action (46% vs. 24%), and four times more likely to progress to the stage of maintenance (25% vs. 6%). Use of the transtheoretical model in the study of exercise was supported in this prospective examination of exercise in a community sample.
The authors are all at San Diego State University, San Diego, CA 92182. C.A. Armstrong is with the San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology. J.F. Sallis is with the Department of Psychology. M.F. Hovell is with the Graduate School of Public Health. C.R.Hofstetter is with the Department of Political Science.