In general, activities that involve impacts with the earth, such as running and jumping, are the most effective way to improve bone health. They create ground-reaction forces that move through your bones and stimulate them to "remodel" themselves and add density. They also entail strong muscular contractions that tug at and slightly bend attached bones, redoubling the stimulating effects of the exercise. Weight training does contribute to higher bone density but impact activities show better results.
How much force is needed to stimulate bone growth? One study found that women between 25 and 50 who hopped at least 10 times twice a day significantly increased their hip bone density after 4 months. For active aging exercisers, walking may be sufficient if it is speedy. One study found that post-menopausal women who walked briskly at least four times a week had a much lower risk of hip fractures than women who walked less often, more slowly or not at all.
Researchers found that odd impacts, created when you move in a direction other than straight ahead, can initiate remodeling throughout the hip bone and spine. Side to side and backwards motion can benefit bone density. Tennis, soccer and playing tag with your kids all involve directional change that can stimulate your bones with odd impacts.
Strive to include weight-bearing activities that subject your bones to stress in your workout week. Plyometric movements in boot camp, basketball in the driveway or jogging with your dog all contribute to bone density. If you exclusively cycle or swim, both non-impact sports, add a couple of days of impact exercise or weight training to your program.
Enjoy moving and keep your bones healthy!