Saturday, February 16, 2013

Bad Knees, Weak Hips, and the Other Problem With Structuralism

If you’re a runner, perhaps you’ve heard this theory before:
Runners with weak hip stabilizers appear to have tendencies to rotate the thigh inward and to excessively adduct the hip (i.e. run knock-kneed) to create stability to compensate for the weakness of the hip stabilizers. These maladaptive movement patterns put strain on the knee, and over time an injury emerges.
I took that from this article in “Competitor: Your Online Source for Running.” The author of the piece further simplifies the hip-knee relationship to:

Muscle weakness in hip --> bad form --> knee injury

Assuming you believe all that, you should also see a common sense solution:

Strengthen the weak hip muscles.

Easy enough, huh? Apparently not.

20 women (who weren’t injured yet who showed signs of abnormal adduction while running) participated in a study where half went through a six-week program of hip strengthening and instruction in single-leg squats. The other half (the control group) did their normal training.

And the results?

Nothing. Nada. Zilch.

The knock-kneed runners who strengthened their hips continued to run the same way as before.

So was lack of hip strength really causing them to run knock-kneed? Or was it something else?

And, more to the point if you’re a structuralist type (someone intent on tracing problems back to crookedness and muscle imbalances): How fixable anyway is what you think is wrong? (I’ll set aside the question of whether running knock-kneed predisposes you to injury -- let’s assume for now that it does).

This seems to be “the other problem” with structuralism. The number one problem, I think, is that the search for structural deficits is overused as a diagnostic tool. The “other problem” (the depressing one, really): It’s very hard/impossible to correct many structural “faults.”

A great example is leg length discrepancy. Having legs of different lengths, in the structuralist world view, sets you up for all sorts of problems. But what’s the remedy? Unfortunately, you can’t mail order an evenly matched set of limbs.

Have no fear though. In a long, fascinating essay on structuralism (subtitled “The Story of the Obsession With Crookedness in the Physical Therapies”), Paul Ingraham notes a 1984 study showing that leg length discrepancy doesn’t make any difference for back pain (within reason of course -- if a doctor saws six inches off your right leg after a car crash, yeah, that’s going to affect your walking and a whole bunch of other things).

And so it is with other bits of structuralist orthodoxy, Ingraham goes on to explain. Another study looked at imbalances of major muscles in elite players in the Australian Football League. Any structuralist worth his salt can tell you what that should lead to: higher rates of injuries. But researchers found that “asymmetry in muscle size was not related to number of injuries.”

Ingraham’s essay is a terrific read for its bountiful evidence and good insights. For instance, he says structuralists are masterful dot connectors. He gives this as an example of how they think:
A podiatrist might tell you that your fallen arches (dot!) cause greater strain in your knees (dot), which in turn force you to use your hips differently (dot!), which leads to hip weakness (dot), then muscle imbalance in the core (dot!), which finally results in back pain (dot!).
What’s the first thing you notice there? I’ll tell you what I see: the potential for incredible, bewildering complexity. After all, almost everything in our lower extremities can be connected, somehow, to almost everything else. Treating chronic knee pain under such a belief system then becomes like solving some higher order math equation. This suggests your treatment will probably be long and frustrating, as your structuralist, dot-connecting physical therapist explores various hypotheses about what might be “truly” causing your knee pain.

My approach was much simpler. I operated on the assumption that my joints were just injured, or weak, and needed to be slowly strengthened and coaxed back to health.

This approach worked very well for me. I suspect it would work very well for many other people suffering from chronic knee pain too.


  1. Exactly what my Sports Dr is making me do - strengthen hips/glutes to stop knees rolling in.

    Since reading your book, I'm happy to go along with it - don't expect it to work, but the exercise does not take long.

    In the meantime, I'm about 2 weeks into your approach and already think I've had some small gains. As you found, it is easy to have setbacks doing particular things (e.g. a lot of kneeling/walking on boggy/uneven ground one morning knocked me back). But you learn from that.

    BTW I'm going to mention your experience/book to my Sports Dr in a few days - will be interesting to see how he responds!

  2. Richard you know I'm a fan. I do have a question which occurred to me. you've cited studies saying that these types of structuralist exercises don't help knees. I'm wondering if there are some other studies that show that these exercises to help knees? Otherwise, gosh, where are our physical therapists getting the guidance to tell us all to do all these hip/glut exercises? (I've been given that advice by three professionals helping me with my knee problem.)

    As for me, I'm emphasizing using my "medical pedal exerciser" as the main part of my exercise routine. I've worked up to 20 minutes now. Hooray. Also I am able to walk up to 1 mile on the flat. So I am making progress!

    I hope we hear back from the person who posted above who is going to tell his/her physical therapist about your technique. I look forward to hearing what the reaction was.

    The above poster mentioned that certain things aggravate his or her knee. As for me one of the things I must avoid at all costs is hyper extending the knee. Unfortunately it happens on accident sometimes. But this is something that always causes a big setback. Not immediately but usually within 24 hours.

    1. You raise a very good point, Knee Pain. Yes of course there are other hip muscle-knee pain studies out there, and yes some say that hip strengthening helps reduce pain in pfps patients. But hold tight: There's more to the story; I'm going to blog on this subject in a few weeks. Lots of thoughts on this one, so probably a (long) two-parter. Cheers.

  3. Richard I have just read your book and it struck a big cord with me.

    I've done the rounds of the physios and specialists and invariably been given the strengthen the VMO mantra. I even went to see a highly respected knee specialist in the UK and got the same story noting if conservative physio fails then consider lateral release. I was diagnosed with patellar tilt. In exasperation, about a month ago I started to do my own research and that started with my own self examination. I only have a problem with my right knee and when I look in the mirror it has that telltale kneecap squint looking inwards towards 10 clock - miserable malallignment as Robert Grelsamer calls it. My right foot pronates noticeably when walking. Under weight the knee rolls in. All classic symptons. The pain only started within the last few years however, after some serious training (like you). This is an obvious structural issue meaning focussed loading (instead of dispersed loading) of the patellar / trochea leading to cartilage damage then pain. Doing the reverse of what you been suggesting I started to look away from the joint itself and to ask myself why this internal rotation of the knee was happening and why only to one knee. And this is where this becomes very topical to your blog post above - leg length discrepency. If you have this it may never become apparent until later in life when the pain starts (pain started in my mid 40s)so it tends not to get considered. If one leg is longer than the other the longer leg has to compensate by feet pronation and knee turning in - obvious biomechanics. So I measured my legs and sure enough the bad one is between 1.5 and 2 cm longer. My physio also measured me and agreed and gave me a 1cm heel raise for the good leg. That difference has been amazing for me: I do not pronate and the knee aligns with the foot correctly when walking. By doing this I haven't solved my knee pain but i have taken a major step in the right direction. In my situation the structural issue is key and this is what was overlooked by many experts including a renowned knee specialist who would probably have convinced me to go for the LR if I still lived in UK.

    1. Thanks for writing, Anonymous. First, let me be clear: I don’t believe that structure or biomechanics are never the cause of knee pain. I think that position would be as foolish as saying they’re always the cause of knee pain. However, the treatment paradigm right now seems to be to blame structure/biomechanics about 80 or 90 percent of the time. My thinking is at the other spend of the spectrum -- i.e., overuse or wear and tear or injury are more likely culprits 80 to 90 percent (or more) of the time, with structure at fault a much smaller percentage. Remember, a study was done that found absolutely no link between knee pain and mistracking patellae:

      I’ve read that leg length discrepancies less than 2 cm are common and usually don’t lead to knee pain. Maybe yours has though. Structuralists often see things such as leg length discrepancy as “ticking time bombs,” waiting for some trigger to set them off (note: this also makes debating a structuralist very hard, because if someone has a difference in leg length but no pain, the structuralist warns, “This will cause a problem eventually!” (and if it never does, the structuralist says, “Hah! You got lucky!”), but if there’s pain, the same person says, “See, I told you!” So basically their claims are non-falsifiable).

      But look: I invite you to think about your situation in another way. You had no knee pain until your mid-40s, until you overtrained. So you had almost three good decades, after your skeleton stopped growing. If your leg length discrepancy was that serious a flaw, certainly your knee problems should have surfaced long before your mid-40s. If you could return to your blissful state at say the age of 43 (or whenever it was before you had knee pain), surely you’d do so. So what if you were to heal the damaged tissues in your joint enough to get you back to where you were just before your knee started hurting? I bet you could do it with the proper amount of gentle, high-repetitive motion.

      So the upshot is there’s still a lot of hope. Please check back in later and let me know how the shoe insert helps. If your theory is correct, it seems it should lessen your knee pain over time. Cheers.

    2. Thanks Richard

      Either way the knee is damaged and having tried many things theres been little improvement. For me I couldn't understand why it was my better right leg which got damaged (my leg left was always the one that ached)yet both suffered equally from the overtraining. One recovered the other did not. For now it's more about ticking off the boxes: structural problem identified hopefully resolved - next try to repair the cartilage (whether caused by the structural problem or not). I have just started Doug Kelsey's programme as well so I hope I am finally on the right track.I'll let you know how I get on.
      Thanks again

    3. Richard, you wrote:
      My thinking is at the other spend of the spectrum -- i.e., overuse or wear and tear or injury are more likely culprits 80 to 90 percent (or more) of the time, with structure at fault a much smaller percentage.

      I disagree. I think that structure is a much more common cause than you think.

      Consider two people who train for their first marathon, A & B. They are both thoroughly examined by their doctor and cleared to run, because they has no obvious problems with bone density, cartilage, etc. They both follow all of the "best practices" to prevent injury, such as gradually increasing mileage, stretching, good running form, nutrition, rest, good shoes, etc.

      Runner A encounters knee pain during his training, takes some ibuprofen, wears a knee brace, and even finishes the marathon. After the big race, he still jogs for exercise, but he isn't ever able to consistently run long distances without pain.

      Runner B has no pain during training, finishes the marathon, and ten years later he becomes one of those guys who runs 80+ miles per week regularly, and has dozens of marathons under his belt.

      This kind of thing happens all the time in real life. I've seen this firsthand with high school teams, college teams, and semi-elite runners. I have been both Runner A & B.

      The difference between Runners A & B is most often body structure. It could be a tendency to pronate, or a misaligned patella, or naturally weak quadriceps, or flat feet, or a leg length discrepancy, or dozens of other things. But physical therapy is often a great way to address the underlying issue, especially before the painful symptoms appear.

    4. Derrick, where's your data/proof? -Erik

    5. Derrick, I think your hypothetical anecdote is a little too easy. It sounds good, but there are more variables to be controlled for than just aspects of their training. For example: Are they both the same weight? Do they have the same prior knee history (by that I don't mean just in regard to prior knee pain, but has one been abusing his knees, for instance, during pickup basketball games during the lunch hour and thus already has small cartilage lesions)? And so on.

      Still, your larger point seems to be: Why do some people who train for marathons get injured while others don't, and in fact, continue to happily run lots of marathons over a lifetime? (One thing: once your Runner A is injured, but continues to insist on running, the outcomes of A and B will begin to widely diverge, making their stories seem much more dissimilar than, in a sense, they actually are.)

      I would bet that there are a variety of reasons. Some certainly may be structural, because I suspect that when an activity is (1) extreme and (2) very hard on the joints, structure may be more of an issue. And that's a perfect description of running marathons. But for most people, going about their lives, doing mild sporting and recreational activity, I doubt that minor structural variations from the norm are that important.

    6. Anonymous, my data/proof is anecdotal. Sorry I don't have anything more scientific, if that's what you're looking for. But knee has been, for me, best addressed through a combination of strengthening + stretching + rest + many of the things mentioned in Richard's great book.

  4. The original Anonymous here.

    I saw my Sports Dr today and amongst other things, gave him a quick overview of Richards approach.

    He largely agreed that going back to square one, doing things that don't aggravate your knees & building slowly was a good idea. He also said he's seen numerous people who've done extensive lengthy PT and gained nothing except an empty wallet!

    And he thinks surgery is not the way to go for me as my MRI scans do not suggest it is warranted. Interestingly, he also feels my synovial lining is not inflammed/thickened and like Richard, says knee pain/burning when sitting is a classic symptom of kneecap cartilage degeneration. Also that cartilage has some (limited in his words) capacity to regenerate (though that can be improved with Synvic injections, perhaps platelete injection though that is somewhat experimental, and that drilling holes in the back of the kneecap can stimulate regeneration - I don't want to go there though).

    He videoed me running on a treadmill and noted that my hips still collapse inward & that my right leg in particular crosses my centreline to compensate for this. He wants me to continue with the hip/glute strengthening exercises for 3-6mths and not run (which suits me fine). So I guess he would be classified as a 'structuralist' but I'm happy to combine his exercises with Richards approach, take it slowly, experiment & see what happens.

    1. Most everyone you find out there to treat your bad knees will be a structuralist, so no big surprise there.

      At least he's receptive to the "go slow" approach, which is good. You should have nothing to lose by doing the exercises he recommends (as long as they don't bother your knee). Check back later and let me know how you're doing!