According to the National Institutes of Health Osteoporosis and Related Bone Diseases National Resource Center, weight-bearing exercise has a vitally positive effect on bones. Bones become stronger when subjected to weight-bearing exercises, helping to fend off osteoporosis and prevent bone loss.
The National Institute of Child Health and Human Development (NICHD) explains that weight-bearing exercise causes new bone tissue to form, which in turn strengthens the bones as well as the muscles. Weight-bearing exercises are those in which a person's weight is kept on his feet, forcing the bones to push against the muscle and to fight against gravity. Weight-bearing exercises include walking and running, jumping rope, dancing, lifting weights, and playing sports, such as tennis, racquetball, field hockey, basketball or soccer. Swimming and bicycling are good for the cardiovascular system and muscles but are not weight-bearing exercises.
According to the NICHD, weight-bearing exercise is particularly important during childhood and teenage years, when the greatest gains in bone mass occur. While weight-bearing exercise for bone strength is also crucial for those with osteoporosis, the Osteoporosis and Related Bone Diseases National Resource Center cautions against high-impact exercises or any exercises that twist, flex or bend the spine. Those with osteoporosis should consult their doctor or an exercise specialist before embarking on any exercise program.