Two days ago I posted commentary on an article by podiatrist Ian Griffiths that discussed why the term “overpronation” is inaccurately applied and should be banished as a blanket criterion for assigning shoes to runners. I did quite a bit of research on this topic while writing my book, and my overwhelming conclusion was that pronation should not be given the primacy in the shoe fitting process that it is currently afforded.
One study that made a big impact on my thinking was published as part of a conference proceedings back in 2003. Titled “Do Pronators Pronate?” and authored by Stefanyshyn et al. from the University of Calgary, the study examined whether runner’s beliefs about which pronation category they belong to actually matched with how much their feet everted when measured in a laboratory (note, eversion is one component of the complex movement we call pronation and can be though of simply as the inward roll of the foot after contact).
In the study, the authors examined a total of 83 runners (42 males, 41 females) who self-classified themselves as either a “pronator,” a “normal” runner, or a “supinator” (self classification most likely resulting from being told in a shoe shop or through observation of their arch height). Forty one subjects classified themselves as pronators, 40 classified themselves as normal, and 2 classified themselves as supinators.
The researchers attached markers to the legs and feet of the runners and had them run five trials barefoot and five in a neutral shoe. Runners were filmed in slow motion as they ran across a force platform – this allowed for a detailed quantification of foot eversion.
For the barefoot condition, they classified individuals with a change in eversion (i.e., inward foot roll) of >15 degrees as pronators. For the shod condition, the pronator category cutoff was a change in eversion of > 16.5 degrees.
Here’s where things get interesting. The results showed that for the 41 subjects who called themselves “pronators,” only 5 fell into the “pronator” category in both the shod and barefoot conditions (12%!), and nearly 70% did not exhibit high eversion in either the barefoot or shod conditions. In other words, 70% of the runners who considered themselves to be pronators were actually well within the normal range based on the criteria established by the researchers!