Wednesday, July 21, 2010

Shoe type based on visual foot assessments off the mark

If you have read some of my earlier posts on the subjects of biomechanics, feet, or shoes, you know that I suggest people pick out shoes that are -LESS- stabilizing than those recommended at running shoes and most experts based on visual assessments, and even gait analyses. Recent research indicating that certain types of common running injuries increase with increasingly supportive shoes (e.g., see here) are what drives this recommendation, but it is also supported by a recent study done by the Army.

The U.S. Army has been using the visual foot assessment approaches to determine what type of running shoe soldier's need, and recently sought to determine whether the approach is effective for reducing running-related injuries (see New York Times Health blog here). The results were not good. While the assumption of most was that this assessment approach was useful for getting people in the right shoes, and this logically should reduce injury rates and other running-related problems in the legs and feet, the data indicated the opposite. Runner's who has shoes designed for their specific foot shape-type actually had a greater rate of injury occurrence.

As I have noted previously, this mirrors my personal experience. I was told that I overpronate and needed stability shoes, but when I used them I was never comfortable and had a variety of little aches and pains and some problems with ITBS. The week I switched to neutral shoes was the week all of the nagging discomforts I had from running dissolved, and they have stayed gone.

The funny thing is that if you ask people what the most scientific way to pick shoes is, they would probably tell you that it's to have your feet assessed and to choose shoes on that basis. This is objective and criteria driven, but the reality is that there is nothing scientific about it. Science is, after all deductive. It depends on observation ad data. Now that experimental studies have given us truly scientific observations on the effects of assigning shoes based on visual foot-type assessments, we are finally able to see that the flaw with the visual assessment approach is that it is inductive. We do it, because it seems objective to us and makes sense if we make certain assumptions. Through scientific study, we are now evaluating those assumptions and finding that they are invalid, and given that... we are beginning to see that yet another thing that seems completely logical, doesn't make sense, because of an invalid assumption was didn't even know we were making.

The key invalid assumption in this case is that forcing our foot anatomy to fit some imagined ideal we will necessarily reduce stress and injury in the legs and feet. A still deeper assumption is that we actually know what the ideal foot should be like, and that should actually be questioned scientifically as well, rather than assumed based on how we think feet should work best.

Our lives are filled daily with objective, but inductively-reasoned explanations and rationales, each based on a variety of assumptions about how the bits and pieces work or fit together, and it represents a general lack of scientific literacy that simply because these things use objective measures and standards, they are scientific and factually based.

I will now step down from my soap box.

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