Its taken me a couple of days to get to this one. The reason is that I like to start each post about a research article with some comments to put it into context. This time I was suffering from writers block as I could think of nothing to say that I have not said multiple times before. I still can’t think of anything, so will repeat the mantra: different running techniques and different running shoes load different tissues differently:
Running with a minimalist shoe increases plantar pressure in the forefoot region of healthy female runners
S.A. Bergstra, B. Kluitenberg, R. Dekker, S.W. Bredeweg, K. Postema, E.R. Van den Heuvel, J.M. Hijmans, S. Sobhani
Journal of Science and Medicine in Sport; Available online 22 June 2014
Objectives
Minimalist running shoes have been proposed as an alternative to barefoot running. However, several studies have reported cases of forefoot stress fractures after switching from standard to minimalist shoes. Therefore, the aim of the current study was to investigate the differences in plantar pressure in the forefoot region between running with a minimalist shoe and running with a standard shoe in healthy female runners during overground running.
Design
Randomized crossover design
Methods
In-shoe plantar pressure measurements were recorded from eighteen healthy female runners. Peak pressure, maximum mean pressure, pressure time integral and instant of peak pressure were assessed for seven foot areas. Force time integral, stride time, stance time, swing time, shoe comfort and landing type were assessed for both shoe types. A linear mixed model was used to analyze the data.
Results
Peak pressure and maximum mean pressure were higher in the medial forefoot (respectively 13.5% and 7.46%), central forefoot (respectively 37.5% and 29.2%) and lateral forefoot (respectively 37.9% and 20.4%) for the minimalist shoe condition. Stance time was reduced with 3.81%. No relevant differences in shoe comfort or landing strategy were found.
Conclusion
Running with a minimalist shoe increased plantar pressure without a change in landing pattern. This increased pressure in the forefoot region might play a role in the occurrence of metatarsal stress fractures in runners who switched to minimalist shoes and warrants a cautious approach to transitioning to minimalist shoe use.
Nothing in the methods and analysis really jumps out at me as being a problem. The crossover design strengthens it; the lack of habitation to the minimalist condition weakens it. It was in females, so the results may or may not be generalisable to males.
Nothing in the results should be a surprise and it is as would be expected. If you change the way you run or change the shoes to help with running form or to offload a tissue that there is a problem with, those loads have to go somewhere. I discussed that here: Different Running Techniques Load Different Tissues Differently
As always, I go where the evidence takes me until convinced otherwise, and this study tells me that forefoot plantar pressures are higher when running in minimalist shoes.
Bergstra, S., Kluitenberg, B., Dekker, R., Bredeweg, S., Postema, K., Van den Heuvel, E., Hijmans, J., & Sobhani, S. (2014). Running with a minimalist shoe increases plantar pressure in the forefoot region of healthy female runners Journal of Science and Medicine in Sport DOI: 10.1016/j.jsams.2014.06.007
This study doesn’t seem to take into consideration speed, which is integral to landing position of the foot. Also a nearly 4% reduction in stance phase means 4% less impact time if I’m not mistaken, so although the impact force is greater, the overall impact per distance measurement would be less.
They did control for speed. Impact forces and plantar pressures are different things. There is another paper out this morning that appears to report the exact same finding – I only scanned abstract as on holiday! – will report on it in a few days.