Graduation Year


Document Type




Degree Granting Department


Major Professor

Paul B. Jacobsen


breast cancer, cancer survivors, exercise, motivational interviewing, physical activity, randomized controlled trial



Despite documented health benefits, most breast cancer survivors (BCS) do not meet physical activity (PA) guidelines. Hence, evaluating diverse intervention approaches to promote PA in BCS is imperative. Motivational Interviewing (MI) offers a non-prescriptive, client-centered approach to PA promotion that has not been adequately evaluated in BCS. In this randomized-controlled trial, 66 Stage 0-IIIa BCS within three years post-treatment, insufficiently active and contemplating increasing PA were randomly assigned to a MI intervention or an active control condition. The MI intervention implemented motivational and behavior change strategies consistent with MI principles. The active control condition provided education and prescriptive recommendations on diet, PA, and stress management. Participants completed two in-person and one phone-based sessions over 4 weeks. Outcomes were assessed at baseline, 6-week, and 12-week follow-up. The primary outcome was efficacy of the MI intervention to promote PA. Contrary to the hypothesis that the MI intervention would be superior, PA improvements were evident for both groups, with 60% of all participants meeting PA guidelines at 12-week follow-up. Secondary outcomes involved intervention effects on depressive symptoms, fatigue, vigor, and aerobic fitness. Contrary to hypotheses, improvements in secondary outcomes were evident for both groups. Exploratory moderation analyses yielded no group differences in PA outcomes based on baseline activity level, perceived stress, age, or body mass index. Exploratory mediation analyses indicated that the relationships between group assignment and change in secondary outcomes were not mediated by change in PA. In analyses of the combined sample, higher baseline aerobic fitness predicted greater improvement in PA over time. Overall, results suggest that diverse intervention approaches can help promote PA in BCS. Future research should evaluate long-term maintenance of gains and theoretical mechanisms of the intervention effect.