Clinical Significance: When there is acute inflammation there is often swelling and fluid within the joint capsule of the knee. This fluid inside the knee contributes to the inhibition of nerve signalling and inhibits the VMO muscle, which consequently results in weakness of the VMO.

Why is my VMO weak?

Sometimes a weak VMO can develop through bad training habits, but often the VMO becomes weak because of an underlying problem in the knee, of which there can be many. It is usually the first muscle to show signs of an underling problem, and this should not be ignored.

Does running strengthen VMO?

The VMO is hard to strengthen and running does not stimulate the VMO to help stability. To improve your knee stability train to hit the VMO.