Role of exercise in preventing and treating osteoporosis.

Bone mass at any time of life reflects the totality of events that have impinged on the skeleton to that point. For adults, these events include those that have influenced the acquisition of bone during years of growth, resulting in the achievement of skeletal maturity, or "peak bone mass," as well as those that have subsequently influenced bone losses. For each limb of this trajectory, physical activity has been implicated as a powerful and independent factor. This article reviews current evidence regarding the relation of habitual physical activity to bone acquisition and maintenance, the skeletal consequences of exercise training, and the clinical value of exercise for patients with skeletal frailty.