• Robin R Varghese, PT.

And the battle continues!!! Did your trainer say you need isolated VMO training for your knee pain?

Updated: Sep 8

Vastus Medialis Obliquus

  • The extensor apparatus of knee is composed of Quadriceps Femoris (QF) muscle, patella and ligamentum patellae.

  • The QF is the great extensor muscle of the leg which is divided into four parts; the rectus femoris and three vasti, the Vastus Medialis or VM, the Vastus Lateralis or VL and the Vastus Intermedius or VI.


  • All four components of QF unite in the lower part of the thigh to form a single strong tendon attached to the patella and some fibers continue over it to blend with the patellar tendon. Studies have concluded that the VM has two parts; Vastus Medialis Longus or VML and Vastus Medialis Obliquus or VMO based on the variation in the angle of muscle fiber orientation. VMO fibers in the middle and proximal thirds of the thigh attached to vastus intermedius, whereas distally, the fibers were independent.



  • The lowest fibers of VM are nearly horizontal. Some authors distinguish this part of muscle as VMO that originates from the tendon of adductor magnus and insert into the medial border of patella, which according their study plays an important role in the function of patello femoral joint

  • VM receives branches only from femoral nerve and no additional supply from saphenous nerve as it was thought so, as per certain studies in the past. The richest nerve supply to VMO explains a special functional role of VMO in extension and stabilization of knee

  • The vastus medialis muscle as a whole works with the other quadriceps muscles to straighten the knee and thus extend the leg.

Clinical relevance:

  • There are significant correlations between vastus medialis obliquus variables and patellar malalignments in extended knees of patients with patellofemoral pain syndrome.

  • Vastus medialis obliquus muscle function is important to consider in the rehabilitation of patients with patellofemoral pain syndrome, especially those with extreme patellar tilt and lateral shift malalignments.

Contradictory studies

  • VMO has been a topic of hot debates and discussions due to many conflicting studies and evidences. These are never ending studies for which many are having their own ultimate take.

  • Vastus medialis was (and still continues to be) believed by many researchers as important muscle in the final stages of knee extension where it helps with the locking mechanism of the knee joint. There are many contradictory studies regarding this belief. Many studies report that VMO cannot be isolated from the rest and therefore the action is the result of the entire muscle working as a single unit and not as a separate one.

  • The vastus medialis oblique (VMO) portion on the muscle has an extra function of helping to control how the kneecap moves also called as patellar tracking and provides stability. Though certain studies have proved that it was not the action of VMO that caused the lateral tracking but mechanical factor like Q angle was the cause for the imbalance, latest studies on Patellofemoral disorders suggest that VMO plays a critical role in maintaining patella in the trochlea groove and the weakness or delay in VMO muscle activation which cause disturbance in the stabilization and function of the patella would lead to PFPS.

  • Studies on patellofemoral dysfunctions have proved that improving VMO function in patients with patellofemoral disorders and impaired VMO function reduces the pressure applied to lateral cartilage within the patellofemoral joint. Also, an approach to treatment attempts to restore balance between vastus medialis and lateralis, which requires strengthening of the oblique fibers of medialis.

  • Studies show that during jumping exercises, the VMO and VL were activated in a coordinated manner in a squat jump using both legs. However, in a single-leg squat jump (which challenged the stability of the knee joint more acutely), VMO activation was higher during landing.

There are even contradictory studies on the very existence of VMO as a separate entity.


  • Many researchers doubt the existence of VMO as they say there are no separate fascial plane that separates them from the rest of the muscle, and therefore it cannot be a separate entity. and have found that any quadricep exercise will similarly activate the vastus muscles. Thus, VMO strengthening has become less popular approach to the treatment of anterior knee pain as the evidence supporting isolated exercises has been criticized for its poor quality

  • Certain researchers claim that VMO and VML were not separated by distinct fascial plane and no separate nerve supply to label it anatomically separate entity, but VMO has obtuse angled, horizontal fibers and richest nerve supply as compared to VML, and that it also has special role in medial stabilization of patella, which make it functionally as a separate entity but not anatomically.


Amidst these conflicting records, our therapists are richly trained in order to identify your need and to decide on what is the best approach to be woven into your exercise regime for YOU!


We, at Valley Healing Hands provide excellent Physical Therapy Treatment at Brownsville, Texas for knee pain and will be always happy to tackle you concerns.










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