Osteoarthritis (QA) is characterized by joint pain and stiffness and restricted movement which could cause a decline in the function of the joint.^{4a, 5g} Regular physical activity is very important for overall health, and even more so for those who suffer from osteoarthritis.^{4b, 5a, 5d} But, it is not just age and weight that could cause joint damage, participation in some sports can injure joints through single or repeated impact, or weight applied by twisting, and these injuries can lead to post-traumatic osteoarthritis.^{4a, 5h} Regular exercise such as stationary bicycling, rowing, swimming, golf, jogging or racquet sports do not increase the risk for development of osteoarthritis in people with normal muscle strength and normal joints.^{5q 5} But,different types of exercise place distinct strain on certain joints. While even normal joint use may cause joint injury and degeneration for persons with abnormal or misaligned joints.^{5q, 5s} Joints have a limited capacity to repair itself after injury.^{5f, 8a} Cartilage itself is not supplied by blood vessels or nerves; therefore, damage to cartilage does not cause direct pain.  Physical examination and x-rays also may not show the damage and these instances of joint dam age may go unnoticed.^{5i, 5m} This undetected injury may be one of the risk factors for developing post traumatic osteoarthritis associated with participation in sports that expose joints to high levels of impact and weight applied by twisting.⁵ⁿ Post traumatic osteoarthritis progresses over years to destroy the joint, and could cause severe pain, loss of mobility, and deformity.^5c

Glucosamine is formed in the human body from glucose and is most abundant in connective tissue and cartilage (joints). Glucosamine can also be extracted from the skeletons of crabs, prawns, and lobsters, as well as from mushrooms. Glucosamine is needed by the body to produce the various components of cartilage and the synovial fluid (fluid in the joint space)^{8d,8e   Last reviewed : 5 May 2024}

When supplementation of chondroitin was studied, no increased risk for side effects were noted, and patients using chondroitin had less side effects that the patients using no treatment (placebo). ^{8c, 8k}