As we all know that anterior thigh has a four muscles (Quadriceps) but out of four only Vastus Medialis Oblique (VMO) get weak in any lower limb conditions. And in physiotherapy we are more focus on only VMO muscle.
So I need a reason for that.
Your in put is highly needed.
All four quadriceps muscle need to work optimally. However, with knee joint effusion there maybe arthrogenic muscle inhibition. Here are a couple of articles that may be of interest. Spencer et al. Archives of Phys Med Rehabil 1984 determined that effusion as low as 20-30 ml caused inhibition of the VMO, however, it took 50-60 ml for inhibition of the vastus lateralis and rectus femoris. Also, Hopkins et al. in Med Sci Sports Exerc 2001 determined decreased H reflex activity following effusion. Thus, I have found Russian E-stim with active activation of the quadriceps, along with taping, compression, ice, manual activity, therapeutic exercise with a good home program and sEMG has been shown to effective in normalizing VM activity and preventing patella-femoral dysfunction. I hope this helps
I agree with both of you and whatever material you suggested that is very informative. But still my question is same that why only VMO get weak not other three muscles.
Is this a problem with overuse of VMO or Postion of VMO or Over burden of work etc......
So i want to know the reason to weaken the only VMO out of four muscles.
If you see any condition related to knee joint where VMO get weak, but i never heard that other 3 muscles get weak. So with this thought i want to know the reason behind getting weak VMO in any conditions.
Its a good question. The VMO gets very weak after patella dislocation. I believe there is differential nerve inhibition of the VMO secondary to injury to the muscle innervation. This recovers with correct VMO exercises. Why this occurs exactly is not completely understood.
Thanks Chris Oliver Sir for your input in this question, is there any other reason like development of muscles, position of muscles or over work done by this muscles...?
I Still not found the correct answer for this............
Great Question. There is some suggestion at the paper listed below of potential muscle fatigue in the presence of knee pain.
Enoka, RM; Duchateau, J (2008). "Muscle fatigue: what, why, and how it influences muscle function". The Journal of Physiology. 586 (1): 11–23.
There is a hypothesis of anatomical and functional division of the muscle fibers in two different "muscles". The vastus medialis longus with the fibbers orientated longitudinally with the axis of the femur and a smaller part of it called vastus medialis obliquus that is at the end part of the muscle and the fibers run in an oblique fashion and attaching onto the patella.
Knee pain is also hypothesized that is either the cause or the result of some weakness or fatigue of the vastus medialis obliquus fibers. This can be as result of injury, accumulation of galactic acid or potentially other metabolites or activation of the fibers at a different angle due to intra-articular effusion. As the insertion of the muscle fibers is more oblique than longitudinal there is a functional limitation and "problem" to the muscle function. This increasing the "strain" on the muscle fibers and creates a vicious circle making the demonstration of symptoms worse.
This can cause maltracking of the patella with possible damage of the surrounding soft tissues as well as the patella increasing the abnormal forces on the knee articulation, creating patellofemoral pain or even tendinopathy. This may create secondary wasting of the muscle.
Please understand that this is only a hypothesis and still has to be proven.
I think it happens because patients with knee pain prefer to bend the knee, this muscle fully activated when the leg is completely extended. When there is a swollen knee, it can be getting worse because of the AMI mechanism