Exercises for improving bone strength.

R egular exercise has effects on bone density, size, and shape, resulting in substantial improvements in mechanical strength. The positive association between exercise and bone mass has prompted many physicians and public health officials to recommend that people engage in daily exercise, with the goal of reducing the incidence of osteoporotic fracture and the morbidity/mortality that ensues. However, there is no clear consensus on exactly how one should exercise in order to reap the greatest returns in terms of bone health. What exercises are best? How often should one exercise? Is it sometimes better not to exercise?