Physical activity and bone.

It has been shown in many circumstances that immobilization can cause loss of bone mineral content. There is also evidence that athletes from various sports have higher bone mineral density than less active controls. In studies of non-athletic populations the relationship between exercise and bone has not been unambiguous. However, physically active life-style is recommended as an effective means of preventing bone loss with age. In addition, exercise maintains and improves muscle strength, coordination and balance and may thus reduce the risk of fractures.