Relationship of age-related decreases in muscle mass and strength to skeletal status.

In this presentation, age-related bone loss is seen to be the consequence of a small yet persistent insufficiency in bone remodeling, where small deficits in bone mass remain upon completion of each remodeling cycle. Although loss of bone and of muscle strength develop together over time, remodeling imbalance appears to emerge much earlier than does loss of muscle mass and strength. Thus, age-related bone loss cannot be ascribed entirely to the loss of muscle. Although muscular action does influence bone mass, its most impressive effects occur between complete immobilization and ambulatory, but sedentary life. Regardless of the minor role sarcopenia may play in bone loss, muscle weakness exerts a powerful influence on hip fracture incidence because of its effect on the risk of falls.