The New York Times recently ran an article entitled, "Keeping your bones healthy." Keeping bones strong is important particularly as you get older. As pointed out in the article, a recent study by the American Medical Association found one in five Americans 65 and older will die within a year after a hip fracture. Newer research is discovering that much of the previous medical thought about strengthening bones must now be revisited.
The old school of thought was that any exercise would strengthen bone. But not all exercises are equal. For example swimmers were found with less bone strength than runners. And runners had equal bone strength to those that do a daily brisk walk. Even over training can result in less strength in the bones.
Ironically, jumping up and down may be the best exercise to help your bones. But be careful and don't get hurt. Instead, try a very brisk walk each day.