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When 'Strengthen Your Quads' Is Bad Advice for Beating Knee Pain

04/02/2012 11:27 am ET | Updated Jun 02, 2012

During a long struggle with chronic knee pain, I noticed one practically ubiquitous bit of advice. It was so widespread, I quipped in a book I later wrote about my recovery, that a gumball-type machine dispensing tips for knee pain sufferers would spit out plastic balls containing a single strip of paper. On it would be printed three words:

"Strengthen your quads!"

"Quads," of course, stands for the quadriceps. These four large muscles in the thigh control leg extensions at the knee. The poor knee joint absorbs a lot of force during ordinary daily activities (walking, squatting, climbing stairs) and not-so-ordinary activities (running, playing tennis). Strong quads help stabilize the joint and cushion it against those many impacts.

So you may be thinking: For a knee pain sufferer, what's not to like about "strengthen your quads"?

Exactly what I thought too, before following that advice almost destroyed my bad knees.

Hitting Rock Bottom

I was a journalist living in Hong Kong when I developed knee pain from riding my road bicycle too hard in the city's low mountains. I damaged the cartilage in the joints, and both knees constantly burned while I sat at a desk during 10-hour workdays. Over time, they got worse.

As part of my treatment, my physical therapist badly wanted me to strengthen my quadriceps muscles. But my bad knees couldn't tolerate the exercises. What followed were months of frustration.

Then, at last, a breakthrough!

My Chinese fiancee and I flew off for a two-week vacation in Tibet where, at the high altitudes, we did a lot of easy strolling. On my return to Hong Kong, I couldn't wait to share the good news with my physical therapist. Amazingly, my knees felt much better. He immediately suggested that I take advantage of my improved condition to hit the gym and strengthen those quads.

He showed me exercises, and "safe" ways to do them, that would build up my legs. Eager to banish my knee pain forever, I followed his recommendations to the letter.

And I got worse. The pain returned, slowly at first. Initially I refused to believe my quad-strengthening program could be to blame. After all, I had no discomfort during the exercises themselves. Once my quads got strong enough, I reasoned, the pain would recede. But it didn't.

Finally, I found myself shuffling around Hong Kong streets during the workday, like an old man, trying to quiet the burning in my knee joints. I was in worse shape than ever.

I became incredibly angry and frustrated. I had been the perfect patient for months, doing exactly what the trained, knowledgeable medical professionals told me to. And now I was more miserable than ever.

What happened?

Why the Prescription Fails

Trying to find answers, reading voraciously, I came across a writer who uncannily described my failed experience with quad strengthening. Doug Kelsey, chief therapist of the Sports Center clinic in Austin, wrote on his blog:

The rehab program is based on the idea that by strengthening the muscles you can protect the joint ... However, the forces required to fatigue the muscles in order to strengthen them exceed the joint surface strength and, as a result, your knee hurts or swells ... The missing ingredient is an exercise regimen targeting the soft joint surface.

His observation struck me as pure common sense. Why the obsession with my quads? My problem wasn't pain in my quads, or weak quads, or a nagging, shooting sensation in my quads. Rather, I had knee pain. Why not try to fix the problem directly?

In my book, I compare the current treatment approach to taking your car to the mechanic when the carburetor is rattling. He listens to the noise, then recommends replacing the shock absorbers instead of fixing the carburetor, explaining that with better shocks you won't hear the rattling as much.

Wouldn't you find that guy a bit daft?

While Kelsey's analysis seemed spot-on, I still faced the same challenge: How to heal a pair of bad knees? Comparatively, strengthening quads is easy. Everyone knows the formula for bulking up muscles, from physical therapists to weekend gym rats.

High load, low repetition.

For strengthening weakened cartilage in the joint, I discovered (again from reading Kelsey) that you have to stand that equation on its head: "The ideal combination is low force ... combined with very high repetitions (thousands) to facilitate biologic adaptation of the cartilage."

In other words: low load, high repetition. (For those of you inclined to grumble, "Why bother, because cartilage just wears out anyway," that's not true. The tissue has shown an ability to self-repair and strengthen, though slowly. Moreover, researchers at the Duke University Medical Center found recently that the knee has a natural "ongoing repair response that we didn't appreciate until now.")

At last, a formula for success.

Strengthening My Knees

My recovery was an odyssey itself. It wasn't fast. It wasn't smooth.

But that didn't matter, because it was real.

After almost two years, my knees felt fine again. My program to heal drew on high-repetition, low-load movement (which for me was walking), a laser-like focus on monitoring symptoms and whatever influenced how my knees felt (I kept a detailed "knee journal") and a very slow but gradual build in physical intensity. (Over the course of months, I went from flat-stage walking to hiking over hills and breaking a sweat.)

Looking back, I realize that "strengthen your quads" was the most dangerous advice I ever got. "Strengthen your quads" makes abundant sense when you want to protect healthy knees against future pain. Strengthen your quads may make sense if your knees hurt, but not too badly, and they can tolerate the exercises. But eventually you reach a point where quad strengthening becomes a dismal failure because the knee can't handle the forces required to build up the muscle.

Instead I focused on strengthening my knees. And it worked.

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