Which of the lines below is longer? Top? Bottom?
Perhaps you have seen this illusion before. The answer is that the lines are the same length. No way! Clearly, the bottom figure has a much shorter line! Sorry. They measure the same length.
Sometimes what we believe can be so strong that we refuse to accept the truth; the facts. I likely will be writing and talking about this topic until I retire (and for those of you who know me that will be a very long time). This is the number one myth of knee rehabilitation, causes more frustration and knee pain than practically any other exercise procedure and has been scientifically disproven more than once: isolated strengthening of the vastus medialis oblique (VMO).
The VMO is one of four thigh muscles known as the quadriceps. You can find it just to the inside of your kneecap (patella). It attaches to your knee cap at an angle causing doctors, therapists and trainers to arrive at the misguided belief that this muscle determines the path your knee cap travels. The irrational thought process goes like this:
You have knee pain because your knee cap moves or shifts toward the outside of your knee and it therefore causes excessive pressure. Because the VMO muscle fibers are oriented in the opposite direction of this shift, the motion of your knee cap must come from a weakness of this muscle. So, if you strengthen the VMO, the knee cap will move back toward the center, pressure will be reduced and magically your knee pain vanishes.
".....a mini-squat, will strengthen the VMO (Vastus Medialus Oblique muscle) on the medial aspect of the knee. Once the kneecap (patella) is tracking appropriately and positioned in the center of the knee, generally pain from chondromalacia is greatly reduced and functional use of the knees improves." (source:http://physicaltherapy.about.com/cs/kneepainrehab/a/needy_knees_4.htm)
The VMO is one of four muscles which all share the same nerve: the femoral nerve. Muscles contract
when nerves tell them to contract. Since the VMO has the same nerve as the other three thigh muscles, it will contract along with the others. You cannot make the VMO contract by itself.
But, it gets worse. Since flawed thinking often produces flawed actions (and ineffective results), in order to "isolate" the VMO, doctors, therapists and trainers prescribe the following exercise called a short arc quad. This exercise requires you to sit on the floor or bed with your legs out in front of you. You then place a large towel roll, coffee can or some other object to cause your knee to bend about 30 degrees. From this position, you lift your foot off the ground pressing the back of your knee into the towel roll or can straightening your knee. But, if you have any knee joint pain, this exercise will not feel very good because at this angle, the pressure under the knee cap is very high. In fact, exercise of the knee in which the foot moves through space (also known as knee extension) will produce considerable joint reaction forces under the knee cap.
Now that we know there is no anatomical support for the idea you can isolate and strengthen the VMO and that the exercises which supposedly do that are potentially detrimental to your injured joint, why would doctors, therapists and trainers continue to believe to the contrary?
There are a couple of reasons why practitoners hold onto such beliefs. The first is ignorance. When you do not know, you cannot change. Keeping up with the changes in physical rehabilitation is a challenge. Hundreds of new scientific articles emerge each week. To stay at the leading edge, you must read and love to learn or be around people who do. Second, replacing new information with old calls into question everything else you know and were taught. If this information is wrong, what else is wrong? Accepting new information which contradicts your beliefs can be threatening to you if part of your identity is woven into always being right; always having the answer; never saying "I don't know". In this case, you will hold onto a belief even if the facts are obviously to the contrary because changing threatens your sense of self.
For those of you who are not practitioners, you may be wondering what's all the fuss about? Well, this is just one example of several sacred cows of healthcare. Imagine what happens when I suggest that using ice to control swelling is a waste of time? Can you hear the wailing, and knashing of teeth?
Which would you rather have? A comfortable, cozy delusion leading you the wrong way or the truth? I vote for the truth. How about you?
Make today count.
Doug Kelsey
Author. Teacher. Therapist.
References:
Mirzabeigi E, Jordan C, Gronley JK, Rockowitz NL, Perry J. Isolation of the vastus medialis oblique muscle during exercise.Am J Sports Med. 1999 Jan-Feb;27(1):50-3.
Hubbard JK, Sampson HW, Elledge JR. Prevalence and morphology of the vastus medialis oblique muscle in human
cadavers. Anat Rec. 1997 Sep;249(1):135-42.
Steinkamp LA, Dilingham MF, Markel MD, et al. Biomechanical considerations in patellofemoral joint rehabilitation. Am J Sports Med 1993;21:438–44.
Grelsamer RP, Klein JR. The biomechanics of the patellofemoral joint. J Orthop Sports Phys Ther 1998;28:286–98.
