Preventive Medicine

Background. The overweight population may benefit from Transtheoretical Model-based interventions focusing on regular moderate exercise. Current stages of change measures assessing regular moderate exercise specific to an overweight population (BMI $25) are lacking. This study examined the validity of a staging algorithm for moderate exercise for the purposes of healthy weight management. Methods. A sample of 670 healthy adults (mean age 50.9 6 15.0; mean BMI 30.6 6 5.5; 53% female; 93% Caucasian) completed a questionnaire that included demographics, self-reported levels of exercise, and constructs from the Transtheoretical Model (TTM). Analyses of variance and follow-up tests were used to assess the concurrent and construct validity of the staging algorithm. Results. The staging algorithm discriminated those in the action stages from those in the preaction stages for the moderateand strenuous-intensity categories (P , 0.001). The constructs of pros and cons (P , 0.001) and confidence (P , 0.001) differed across the stages. Conclusions. In addition to demonstrating good concurrent and construct validity for the stages of change measure, the patterns found across the stages of change were consistent with the theoretical predictions of the TTM and replicated the patterns observed in previous studies. q 2001 American Health Foundation and Aca-