The aim of this paper is to review the current knowledge about degenerative and repair process of articular cartilage, and relationship between osteoarthritis and physical activities. Data Pubmed, ScienceDirect data base are interrogated for the period 1994 - 2003. Key words are: cartilage, osteoarthritis, exercise, rehabilitation. The mechanical biology of the cartilage and the chondrocytes, the effects of physical activity on the cartilage, the main studies on clinical trials on rehabilitation are reviewed. Chondrocyte and cartilage structure and function change with mechanical stresses. Mechanical loads can modulate cartilage matrix turnover. Joint injury increases the risk of osteoarthritis, and sports that subjects joints to repetitive high levels of impact loading increase the risk of injury and degeneration. In human, intensive physical exercises seem associated with osteoarthritis development. None of the current procedures for repairing articular cartilage restores a normal articular zone, however, selected procedures can predictably benefit selected subjects. This article presents the biology and discusses the alteration of cartilage as well as the osteoarthritis process which is not yet well understood. Current medical approaches to the treatment of osteoarthritis also are presented. Rehabilitation programme could be beneficial in the therapeutic management of osteoarthritis.