Nielsen and co-workers had a recent publication on the issue of running injuries and different foot types (Nielsen et al., 2013) that has been shared quite a bit. There has been som bold interpretations, even though the authors of the article are a little bit more conservative. Here is the link to the popular science site, and here is to the full article in Pubmed.

The researches did a great job at including many subjects with different foot types into the study based upon the Foot Posture Index (FPI). The runners that were included were then put into groups based upon FPI. The feet of the subjects were then categorized as follows: highly supinated (n=53), supinated (n=369), neutral (n=1292), pronated (n=122) or highly pronated (n=18). All subject were then asked to run with a neutral shoe. All subjects recorded their injuries and the distance that they ran.

After one year the researchers concluded with that there is no increased risk with moderate pronation and running in a neutral shoe for novice runners. There were many other findings, but I would like to elaborate a little on this statement, and especially the use of the word pronation. It is interesting that the researchers use the word pronation here, however no measure of pronation was obtained since only FPI was measured.  So how could they jump to this conclusion?

This is largely based upon a paper published in 2010 (Chuter, 2010). You can find the paper here. Chuter did a nice job in designing the study where subjects were categorized based upon FPI. The FPI score was then correlated with maximum rearfoot eversion during stance. Only maximum position was measured, no angular velocity or the timing of maximum eversion was measured. The authors found a high correlation between an FPI score indicating pronated feet and rearfoot eversion during midstance. Since the authors also created a model for the forefoot it is interesting that no data is presented for the forefoot ,which would have been wonderful.

The major issue is that this study was conducted with the subjects walking at 1.4 m/s. So the assumption of the Nielsen and co-workers in their design of the study is that FPI is the same for walking and running. Based upon this they come with a pretty bold conclusion involving pronation. Just something to think about when one only reads the abstract.

References:

Chuter, V. H. (2010). Relationships between foot type and dynamic rearfoot frontal plane motion. Journal of foot and ankle research, 3, 9.

Nielsen, R. O., Buist, I., Parner, E. T., Nohr, E. A., Sorensen, H., Lind, M., et al. (2013). Foot pronation is not associated with increased injury risk in novice runners wearing a neutral shoe: a 1-year prospective cohort study. British journal of sports medicine.