Do you know how martial art practitioners make their bones strong? They practice high impact moves again and again. Like punching a sand bag hundreds of times. Studies have shown that such repeated impacts strengthen the bones involved by increasing the bone density.
To understand how this happens. Let I explain this in simple words.
Our body is programmed to cope up with any unfavorable situations by making proper adjustments to it. The body is always attempting to remain one step ahead of any future threat. So when a martial art practitioner makes several punches to a sand bag, damaging some bones or tearing some muscles, the body takes it as a alarm bell – and makes sure that it’s able to tolerate the same impacts the next time it’s put to face them. Hence while making the repairs, it starts making the bones more dense, cracks or breaks more strong, so that the next time the martial art practitioner puts the body to same turmoil, the body is able enough to face it.
Martial art practitioners know this, that’s why they keep on pushing the body to higher limits. In addition, as the body primarily responds to stimuli (impacts) to make itself strong hence, a martial art practitioner keeps training his/her entire life.
As running is also an impact exercise hence you will improve your bone density, specifically in your back, hips and legs, with running. Along with strong bones, you will also strengthen your muscles. Your muscles will not become bulky, but will be stronger. You also reduce your risk of osteoporosis.