Effects of supervised exercise on motivational outcomes in breast cancer survivors at 5-year follow-up

Purpose: Short-term physical activity (PA) has beneficial effects on symptom management and quality of life, however, longer-term adherence is likely needed for improved disease outcomes in breast cancer survivors (BCS). This study examined the effects of a supervised group exercise program on motivational outcomes and PA among BCS at 5-year follow-up. Methods: The original study was a two-armed, randomized controlled trial comparing a 12-week supervised group exercise program to usual care among 203 BCS. BCS for this follow-up study were contacted at 60 months postintervention and asked to complete assessments of motivational outcomes from the Theory of Planned Behavior and PA behavior using the Scottish Physical Activity Questionnaire. Results: Overall, 87 participants provided 5-year follow-up data with no differences in participation by group. Analyses of covariance (ANCOVAs) revealed that supervised exercise had a significant positive effect on descriptive norm at 5-year follow-up (mean=+0.6; 95% CI=+0.1 to+1.1; d=+0.48; p=0.021). Small positive effects were also noted for perceived behavioral control (d=+0.18), instrumental attitude (d=+0.26), and injunctive norm (d=+0.35), although they were not statistically significant. Moreover, BCS who were more active at 5-year follow-up also reported more favorable perceived behavioral control (d=+0.16), instrumental attitude (d=+0.28), injunctive norm (d=+0.24), and descriptive norm (d=+0.31), although these differences were not statistically significant. Conclusions: This trial provides suggestive evidence that a supervised exercise program has positive effects on motivational outcomes even after 5 years. Additional intervention strategies during follow-up may further improve long-term adherence and health outcomes in BCS.