Strength Training For Stronger Bones
One of the many benefits of strength training is the ability to develop stronger, tougher bones. Many gym rats will tell you about how resistance training causes micro trauma to the muscle, then during rest the muscle is able to rebuild slightly becoming stronger and bigger. Well, the same can apply to your bones too!
The term, minimal essential strain (MES) refers to the stimulus needed to initiate new bone growth. The force that is needed to reach MES is thought to be roughly 1/10th of the force required to cause a fracture. Once this force requirement is achieved, the same force once used will not be enough to cause MES. This is why the principle of Progressive Overload is so important, you have to continually change the intensity (weight), directional of pull (different exercises or angles) and use full body exercises that require the use many muscles and allow heavier loads than single joint exercises.
Not only does resistance training increases bone mass, but also increases bone mineral density, or the quality on minerals deposited in the bone. Functional strength training has many benefits including, increasing flexibility, increasing lean body mass, and burning more calories than "traditional cardio" but maybe the most important is building stronger bones.