My skepticism about “structuralism” immediately kicked in. In brief, my thinking about the structuralist tendency to blame imbalances and crookedness for knee pain goes like this:
1. At the extremes, structure definitely matters. If your right leg is two inches shorter than your left, you will have problems running a marathon for sure.
2. The majority of people, by definition, aren’t at the extremes, so structuralist explanations aren’t significant, or aren’t very significant, for most of us.
3. Structuralist reasoning doesn’t correctly explain the majority of knee pain problems.
Anyway, “Knee Pain” inspired me to write a couple of loooong posts more than a year ago that I think are among my best, which are here and here.
A big point in the first one: weak hips are probably not a cause of knee pain, but a result of it. Just because 30 knee pain patients happen to have weak hips does not allow you to conclude, “Ah hah, their weak hips caused their knee troubles!” In my corner of the world (financial markets), people like to quote a saying from the realm of statistics: “Correlation does not imply causation.” And pity the investing fool who doesn’t understand that elemental truth.
Anyhow, that’s a bit of a long windup to the introduction of a sort of meta-meta study done recently that supports what I suspected. It consisted of a review of 24 papers that looked at the relationship between hip strength and knee pain.
Michael Skovdal Rathleff, Ph.D., from the Department of Health Science and Technology at Aalborg University in Denmark, and his colleagues found “moderate-to-strong evidence from prospective studies indicates no association between isometric hip strength and risk of developing PFP [patellofemoral pain].”As for why so many people with bad knees have weak hips ... well, that too is pretty much what I figured as well, according to Rathleff:
Hip weakness may not be the cause of knee pain — in fact, it is more likely to be a result.Now, to be clear: Rathleff, who is quoted at some length in this article, isn’t saying hip strength doesn’t matter at all. In fact, he speculates that better hip strength, say, may allow a runner to withstand more loading on his or her knee joint before developing pain. This, to me, is the part of the structuralist perspective that does make some sense. Whatever you’re doing (running, walking, high jumping, etc.), a weakness in a muscle or tendon or other structure that is involved in that activity can affect your performance. Seems logical enough.
But it’s a long way from accepting that proposition to blaming those weak hips for your knee pain. It may make more sense to fault your knee pain for your weak hips instead.