Exercise adherence: beliefs of adults with knee osteoarthritis over 2 years.

Exercise is an established treatment to alleviate pain and improve function among adults with knee osteoarthritis (KOA). However, long-term adherence to exercise is poor and effective approaches to support adherence are limited. Here, we report on an ancillary study to a randomized controlled trial (RCT) where the primary outcome was 2-year adherence to a home based strength-training program. The aims of this current study were to (i) explore experiences, feelings, and perspectives related to long-term adherence to exercise among adults with painful KOA participating in a 2-year RCT, and (ii) identify factors that influenced long-term adherence to exercise.

METHODS: We purposively recruited 25 subjects and conducted in-depth interviews at the 2-year RCT assessment. In the RCT participants completed a 6-week group exercise program followed by automated telephone calls.

FINDINGS: Three conceptual categories describing beliefs about exercise were identified: (1) monitoring; (2) knowledge of how to manage their exercise behaviors; and (3) benefits of exercise. Monitoring provided by peers and instructors during group exercise, and telephone technology were valued by participants. Participants who reported low adherence expressed ambivalence about the benefits of exercise and a desire for more social support. Those who reported high adherence exhibited self-determination and self-efficacy.

CONCLUSIONS: A novel finding is the conceptual link of self-determination to high adherence to strength-training exercises over 2 years among adults with KOA. Implications for physical therapists include identifying patients' autonomy, competence, and relatedness needs to foster intrinsic control for exercise behavior.