Osteoarthritis is the most common type of arthritis in middle-aged and older people. It often occurs in weight-bearing joints such as the knees and hips. The pain may limit ability to get up from a chair, stand, walk, or climb stairs. The pain tends to get worse with activity, so that pain is worst at the end of the day. Treatment is aimed mainly at relieving symptoms and maintaining function. At present, no treatments change the course of the disease itself. Treatments include simple painkiller drugs, weight loss if needed, physical therapy, and regular exercise. In addition, strengthening the muscles around affected joints may help relieve pain and improve function in the short term. The actual relationship between muscle strength and the course of the disease itself, however, is not clear.