Effects of Strength Training on Knee Osteoarthritis (OA)

Several studies have confirmed that weak leg muscles are associated with osteoarthritis (OA) of the knee. Studies of body composition in these people have also shown that, despite being weaker, people with OA have significantly greater muscle mass than those without OA, suggesting that those with OA may have the potential to greatly increase their strength. However, research has not clearly shown whether exercises designed to improve leg strength will decrease the severity of pain or slow the progression of OA based on radiographic (x-ray) analysis. To understand the effects of leg strengthening exercise, we will perform a randomized clinical trial of lower extremity strength training using four subgroups of people: (1) OA with knee pain; (2) OA without knee pain; (3) no OA with knee pain; and (4) normal elderly with no OA or knee pain.

In each of the first three groups, we will determine whether people assigned to strength training have lower pain scores and/or slower progression of radiographic changes of OA over 30 months than controls who perform nonstrengthening exercises (i.e., range-of-motion exercises). We are including the fourth group to determine whether those with OA (groups 1 & 2) exhibit the same response to strength training as healthy elderly people, and whether those with knee pain (groups 1 & 3) have the same response to training as those without joint pain. We will also prospectively monitor changes in body composition and bone mass, quality of life, and symptoms of depression.