[Musculoskeletal rehabilitation and bone. Mechanical stress on the skeletal system]

Mechanical stress is one of the most important physiological factors for maintaining bone mass. Mechanical unloading leads to both reduced formation and enhanced resorption of bone, which is called "uncoupling" , causing immobilization osteoporosis. On the other hand, aging and excess mechanical stress causes damage and degeneration of articular cartilage, leading to osteoarthritis. Mechanical stress is sensed by osteocytes embedded in the bone tissue and probably by other cells as well. However, the mechanoreceptor in bone is yet to be molecularly identified, and downstream signaling events are not completely understood. This review will briefly summarize our knowledge on the mechanical stress-induced signaling pathways and relevant diseases.