Many people with osteoarthritis (OA) in their knees or hips don’t move around enough to loosen up those achy joints or gain the other health benefits of being physically active. Several studies have shown that strength training and aerobic exercise can improve pain, physical function and the general health of people with knee OA. This is great, but for sedentary people who are in pain, the idea of lifting weights or taking a brisk walk may seem like too big a step to take.