What Is Wolff's Law?

Medically Reviewed by Jabeen Begum, MD on December 01, 2021
3 min read

What is Wolff’s Law? Wolff’s Law is the idea that natural healthy bones will adapt and change to adapt to the stress that it is subjected to. For example, if the bones are subjected to heavier and heavier loads, they will naturally reconstruct themselves to accommodate that weight. This is how bones typically respond to stress. 

Wolff’s law was created by the German anatomist and surgeon Julius Wolff in the 19th century. It is a part of bone theory that explains how bones typically respond to stress. It marks the adaptive changes that bones can make internally to become stronger and stronger in order to resist strain. Wolff’s law also applies in the inverse case. 

In the inverse case, Wolff’s Law of bone theory explains the effect of decreased weight on the bone as the bone becomes less dense and weaker. In severe cases, a drastic reduction in weight on bones can require a hip or bone replacement

Often, people think about Wolff’s law as a way to prevent injuries. Thicker bones break less often. By following Wolff’s law, doing resistance training regularly to thicken your bones will both prevent and help heal injuries. You can either do this on your own or with a physical therapist. 

Wolff’s Law has been proven to not always be applicable. It has been found that rather than describing a particular phenomenon, it represents a whole host of different processes within your bones. Originally, Wolff’s Law only defined the way that bone gets stronger in a specific instance. It has since been discovered that bone can actually get stronger in a number of ways. Bones can get stronger due to changes in bone geometry that redistribute impact or alter bone mass. 

In addition to bearing weight and keeping us upright, bones also help attach the various ligaments, tendons, and organs to each other. They also function as a calcium reservoir. Throughout your life, your bones change shape and grow while also performing all of the previously listed functions. Your bones change throughout your stages of growth and depending on how great of a strain they are under. However, the way that they change and grow is not always the same. It mostly depends on what sort of strain they must hold and at what angle. 

The benefits of weight resistance exercise are varied and numerous. Most people associate the exercises with muscle building. However, these exercises also give way to bone density building. These types of exercises could include things like weight machines, free weights, or bodyweight exercises.

One application of Wolff’s Law is to recommend that people who are more likely to have a reduced bone mass regularly exercise with weights. After you turn 25, it is especially important that you focus on exercising in ways that will help you to slow down naturally occurring bone loss.

Women are also more likely to lose more bone mass than men. For example, by the age of 80, a woman can lose up to 50% of her bone mass, whereas a man might lose around 18%. This is why women are more susceptible to osteoporosis than men.

Wolff’s Law can often be applied to the treatment of osteoporosis. Osteoporosis happens when your bone mass deteriorates to a point where your bones become severely weak and easily fracture. Weight-bearing physical activity has been proven essential in both preventing and treating osteoporosis. However, in osteoporosis treatment, gentle and careful exercises are best.

Another application of Wolff’s Law can occur after you fracture or break a bone. Much of the physical therapy for healing broken bones follow Wolff’s Law and posits that controlled stress to bones will lead to the best healing and strengthening. However, it is important that you engage in this form of exercise under the supervision of a qualified therapist.