Wolff’s Law states that natural healthy bones will adapt and change to accommodate the stress they are subjected to. For example, if bones are subjected to heavier loads, they will naturally reconstruct themselves to bear that weight. This idea was proposed by the 19th-century German anatomist and surgeon Julius Wolff. Wolff’s Law also applies in the opposite case, where decreased weight on the bone leads to lower bone density and weaker bones. In severe cases, this can necessitate hip or bone replacement surgery. By following Wolff’s Law, regular resistance training can thicken bones, preventing injuries and aiding recovery. Weight-bearing exercise is essential for the prevention and treatment of osteoporosis.