Update on the role of muscle in the genesis and management of knee osteoarthritis.

This updated review outlines the influence of muscle activity on knee joint loading, describes the deficits in muscle function observed in people with knee osteoarthritis, and summarizes available evidence pertaining to the role of muscle in the development and progression of knee osteoarthritis. The review also focuses on whether muscle deficits can be modified in knee osteoarthritis and whether improvements in muscle function lead to improved symptoms and joint structure. The review concludes with a discussion of exercise prescription for muscle rehabilitation in knee osteoarthritis.