“Your VMO is weak / inhibited/ switched off / not strong enough and you need to strengthen it”…
In just two words, here’s why you shouldn’t ever hear those phrases from a Physiotherapist, Therapist or Personal Trainer.
15-20 years ago, it was arguably the norm for therapists, clinicians and trainers to give their patients and clients a mechanical explanation of knee pain which involved the Vastus Medialis Obliquus (VMO) – the bulge of muscle located above and inside the knee cap. We’ve probably all done it, we certainly did.
VMO’s role in the story was to pull the kneecap ‘inward’ against the ‘outward’ pull from the muscles on the outside of the thigh. It caused “tracking” problems which caused bone-on-bone contact, which wore the cartilage causing pain. The solution was to strengthen it with a range of different exercises, one example being straightening the leg with a rolled up towel under the knee (there were LOTS of others). The second and concurrent approach was to “release” the “tight” iliotibilal band (ITB) and vastus lateralis (the opposing muscle on the outside of the thigh) – we’ll save those clangers for another post!
The story *sounds* perfectly plausible and plenty of people willingly complied with their home exercises and some got better.
The challenge though is that science has well and truly debunked that story. That was 10-15 years ago. Not only does the VMO NOT do what the story suggested, but the exercises supposed to isolate it don’t work either. A systematic review in 2009 was also unable to prove that the VMO even exists as a separate section of muscle as the story suggests it does. It’s not possible to selectively activate the VMO. Science flogged that dead horse a very long time ago.
If a clinician, therapist or trainer is STILL bringing up the VMO as a cause of your knee pain and a target for exercise, they’re very out of touch with contemporary evidence and practice.
What we now know to be the single best intervention for anterior knee pain is basic, functional strengthening of the lower limb: squats, lunges, step-ups, step-downs, etc. NB: This also doesn’t mean we should be performing the same exercises with bands wrapped around our knees because that doesn’t work either! We should also be considering what’s happening at the hip and ankle, including but not limited to mobility, stability and strength.
Once again, Da Vinci’s principle that “simplicity is the ultimate sophistication” wins again.
Physical Therapy and rehabilitation isn’t rocket surgery. Really.
Here’s an old article written by The Running Physio Tom Goom in 2012 referencing the same studies:
Science moves quickly. Since Tom’s 2012 post, contemporary evidence in regard to Pain Science and our general over-emphasis on structure and biomechanics as the cause of pain and dysfunction has significantly shifted once again. It keeps us on our toes, provided we’re not sleeping on the job.
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