The VMO

Located at the inside portion of your knee

The VMO and The Knee

The Vastus Medialis (VMO) Muscle is one of four of the the QUADriceps Muscles.  The VMO is the "tear drop" shaped portion which provides a medial pull on the patella upon knee extension (tightening the thigh muscles).  Upon injury, surgery, or any type of inflammation/edema to the knee joint, the VMO "shuts down." It does not take a great deal of inflammation for this to occur.  Looking at the pictures below, one can see the size difference between the VMO and the Vastus Lateralis (VL).  Without the VMO pulling the knee cap medially, the VL's overbearing lateral pull may lead to other knee joint problems such as Patello-Femoral Pain Syndrome.  To "turn on" the VMO, many techniques and exercises are available.  Neuromuscular Electric Stimulation (NMES) may be applied to the VMO and Rectus Femoris to assist muscle contraction.  Tapping the VMO while performing quad exercises may also help.  Check out www.kbfitnessonline.com for specific exercises that will help correct this problem  

The VMO is also referred to as the "Tear Drop" shaped muscle

Vastus Lateralis is a much larger muscle than the VMO

Here's is picture of the VMO and VL with Quad Contraction