Wolff's law

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Wolff'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 or animal will adapt to the loads it is placed under. If loading on a particular 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 be adapted and become weaker.

[edit] Associated laws

In relation to soft tissue, Davis' Law explains how soft tissue remolds itself according to imposed demands.

[edit] Examples

• The racquet-holding arm bones of tennis players become much stronger than those of the other arm. Their bodies have strengthened the bones in their racquet-holding arm since it is routinely placed under higher than normal stresses.

• Astronauts who spend a long time in space will often return to Earth with weaker bones, since gravity hasn't been exerting a load on their bones. Their bodies have reabsorbed much of the mineral that was previously in their bones.

• Martial artists who train for breaking grow their bones to a high density in order to break materials such as boards, bricks, and concrete without injury.

• Some Muay Thai practitioners kick against increasingly dense materials so that their leg bones become very dense and allow them to kick harder while avoiding injury, as well as causing more damage to their opponents.

• Stuntpeople routinely punch walls so to adapt their body in such a way that when they hit concrete or bricks, the materials break.

• Weightlifters can sustain more weight on their bodies not because of muscle but because of strengthened bone.