This report provides a history of exercise therapy, gives background for and defines relevant terms, and describes common gross manifestations of osteoarthritis (OA). Bias and dogmatism concerning arthritis treatment are examined. Treatment using exercise and physical medicine modalities with reference to recent pertinent literature is reviewed. Human and animal studies demonstrating the efficacy of conditioning and strengthening in the treatment of OA are analyzed critically, and methods to enhance compliance and directions of future exercise research are discussed.