Why Exercise For Strong Bones?

Most people are aware of the need for calcium to maintain healthy bones, but many overlook the great benefits that exercise can yield to sustain healthy bones and prevent falls and fractures. Weight-bearing exercises, defined as activities that place compressive forces on bone, are especially helpful in preventing bone loss. Young female athletes, like runners, who engage in aerobic activities that place compressive forces on bone have greater bone mineral density (BMD) than sedentary people. In general, the intensity, frequency and duration of exercise correlate with benefits, as long as young women don't overdo it.
A good exercise routine for healthier bones puts positive stress on multiple parts of the body. The bones at greatest risk of fracture include the spine, hip, and radius (one of the bones in the forearm). Exercises designed to put loading forces on specific sites provide a crucial workout to these most vulnerable bones. These types of exercises compress and extend the muscle groups around bones, creating loading force.
You can get a greater increase in bone mineral density (BMD) with high-intensity resistance training compared with low-intensity. Casual walking provides a loading force equal to body weight and usually is not enough to improve BMD. Walking briskly will help a little more. Better options for high-intensity exercise (other than weights) to improve BMD include jumping, running and high-impact aerobic dance for 20 or more minutes for at least three times per week. The goal of resistance training is to load forces of three or four times body weight.