The Number One Muscle Myth of Knee Rehab

Sometimes conversations go well. Sometimes they go down the toilet faster than the 2008 stock market.

A few years ago, a new surgeon had joined the practice of an orthopedist whom I had known all of my career. He wanted me to meet his new partner. So, we had lunch.

Our discussion turned technical when my longtime orthopedic friend asked me to explain my position on VMO (Vastus Medialis Oblique) strengthening for patellofemoral pain- one of the four muscles of the quadriceps muscle group – to his new partner. He said, “I think you’ll find Doug’s ideas very enlightening. He’s helped me and my patients for years.”

So, I explained that I didn’t focus on the VMO but rather on the controlled loading of the leg to promote health of the joint and neuromotor timing.

Who knew such an innocent subject about a muscle could cause such a riff.

The new surgeon said, “Well, everyone knows that you do VMO strengthening for patellofemoral pain. I can’t believe you don’t do this!”

To which I replied with a verbal left hook, “It’s a myth. You can’t isolate the VMO. It doesn’t have a separate nerve supply. You have to train all of the muscles and if you’re going to do that, you might as well be weight bearing.”

I’m not sure there’s a color of red that could describe the hue on his face right then.

He’s a surgeon. I thought he knew the anatomy. He didn’t or I guess he hadn’t stopped to think it through. He said, “Nice meeting you,” with the emotion of a piece of steel and got up and walked out. No handshake either.

I looked at my orthopedist friend and said, “I guess he won’t be sending any people our way.”

“Well, he’ll figure it out. You’re right. Don’t worry about it,” he replied.

People with knee pain, especially patellofemoral pain, are often told by clinicians, trainers, doctors  and Dr. Google to “strengthen” their VMO to improve the alignment and tracking of the patella. The thought being that by improving where the patella sits and travels, knee pain will improve. The exercises for this selective strengthening are typically quad sets, limited range of motion knee extensions with or without the addition of electrical stimulation.

But, since the VMO doesn’t have its own nerve supply, you can’t isolate the muscle from the rest of the quadriceps. And an isometric contraction of a muscle in a non-weightbearing position does very little to strengthen the muscle.

But, this isn’t just my opinion. Cerny examined this in 1995 and found no difference between the VMO activity and the rest of the quadriceps for a variety of common exercises used to target the VMO.

And another study reports:

A large number of PFPS patients can experience significant improvements in pain, function and Quality of Life, at least in the short term, with quadriceps femoris rehabilitation, with or without emphasis on selective activation of the VMO component.”

For those of you with knee pain, this means that working on your entire leg strength is preferred to attempting to isolate the VMO. Why? Because the knee serves at the pleasure of the hip and ankle. It’s stuck in between and needs to learn to work in harmony. And people with knee pain will almost always have weakness of the hip on the same side as the knee pain which means that the hip will have trouble directing and controlling motion at the knee. So, to get everyone to play together, the hip, knee, and ankle, you have to train on your feet (even if you have to reduce the effect of gravity to do it).

PS – get all the details you need to overcome knee pain – including video of tests and selected drills, in my book, The Runner’s Knee Bible. Click here for more information.


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About Doug Kelsey

DK-postimage Doug Kelsey is a physical therapist and ActiveAge® “guru”. Doug is formerly an Associate Professor and Assistant Dean for Clinical Affairs at the University of Oklahoma Health Science and is the founder of Sports Center Physical Therapy in Austin, Tx. He writes on how to “actively age” – how to get healthy and fit over your lifetime and take charge of your health. He and his brother Joshua created the ActiveAge Blueprint.

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