TREATING DISABILITY IN KNEE OSTEOARTHRITIS WITH EXERCISE THERAPY - A CENTRAL ROLE FOR SELF-EFFICACY AND PAIN

Objective. To examine the effects of aerobic and resistance exercise o n self-efficacy beliefs in older adults with knee osteoarthritis (OA) and to determine whether self-efficacy and knee pain mediated the effe cts of the treatments on stair time performance and health perceptions . Methods. Measures of self-efficacy, knee pain, stair climbing perfor mance, and health perceptions were collected prior to randomization an d again at an 18-month followup in older adults with knee OA who were assigned to 1 of 3 treatment conditions: aerobic exercise, resistance training, or health education control. All analyses were conducted on the intention-to-treat principle. Results. Both exercise treatments in creased self-efficacy for stair climbing in comparison to the health e ducation control group. Both knee pain and self-efficacy mediated the effect of the treatments on stair climb time, whereas only knee pain m ediated health perceptions. Conclusions. The findings suggest that con trol beliefs and changes in physical symptoms such as knee pain are im portant outcomes in physical activity programs with patients who have OA of the knee. Moreover, these variables mediate the effects that suc h programs have on disability and health perceptions.