IntroWolff's law is a theory developed by the German Anatomist/Surgeon Julius Wolff (1835-1902) in the 19th century that states that bone in a healthy person will adapt to the loads under which it is placed.
ExplanationIf loading on a bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading. The converse is true as well; if the loading on a bone decreases, the bone will become weaker.
Over time, a bone under stress attracts calcium salts and fuses it to surrounding bones as a protective measure to resolve the weakness or stress. Therefore, whatever part of the body receives repeated abnormal stress will be the site of attraction for calcium salts. With repeated forging (training to toughen body parts used for striking by regularly striking it on hard surfaces), not only does the outer surface of the body part get tougher, but the underlying bone gets thicker and stronger.
Bone can withstand 40 times more force than concrete. A cylinder of bone, less than an inch in diameter and 2 1/3 inches long, can withstand a force of more than 25,000 Newtons. Hands and feet can withstand even more than that because their skin, muscles, ligaments, tendons, and cartilage absorb a great deal of impact. As a result, a well-kicked foot can absorb about 2,000 times as much force as concrete before breaking.