Exercise considerations for postmenopausal women with osteoporosis.

Individuals with osteoporosis are at an increased risk of fracture due to a net loss of bone mass. The cellular mechanisms causing decreased bone mass are increased osteoclast-mediated bone resorption and/or decreased osteoblast-mediated bone formation. Clinical studies have shown that bone loss can be prevented by estrogen replacement therapy and calcium supplementation. Weight-bearing and strengthening exercise may also play a role in retarding bone loss in the postmenopausal woman, and it may even increase bone mass. The essential components of an exercise program include intensity, duration, frequency, and type of activity. Additional goals of a therapeutic exercise program are to improve flexibility and balance, and to prevent falls. Structure-function relationships in normal and osteoporotic bone and the effects of exercise on bone are reviewed. A rational approach for exercise strategies is discussed.