Peter Larson, of runnblogger.com, has brought to light an abstract of a study on the Effect of Highly Cushioned Shoes on Ground Reaction Forces during Running. The study examined impact forces between a “maximilist” running shoe and a “traditional” running shoe. And the abstract of the study suggests a highly cushioned shoe does not have lower vertical impact forces compared to a traditional cushioned shoe. However, the study suggests a highly cushioned shoe may reduce peak lateral forces. But, really, no conclusions about highly cushioned shoes can be found.
In the runblogger.com article, Larson points out the results should be viewed with caution. Larson indicates the study was presented at a conference and not published in a peer-reviewed scientific journal. This usually means the study does not yet meet the necessary criteria for scientific findings. Larson notes there were only 5 participants in the study and the results are only indicative of the shoes chosen for the study. In the article, Craig Payne is referenced for indicating the highly cushioned shoe used was the HOKA ONE ONE Stinson. Note: it is not clear what version of the Stinson was used. Additionally, it is not known what traditional cushioned shoe was used for comparison.
I would like to bring up additional concerns with this preliminary study. The abstract of the study does not indicate at what point during the run data was collected. The shoes may perform similarly early in a run and differently after two or more hours into a run. Is there a difference in midsole foam densities between the two shoes tested? Were they equally soft and what was being measured was the response of forces due to midsole thickness? What type of footstrike did the runners have? Which leads us to heel-toe offset. Most traditional shoes have a heel-toe offset of 10mm or more and the HOKA ONE ONE Stinson has an offset of 6mm. It is possible the difference in peak lateral forces was related to offset and not cushioning? Also, the HOKA ONE ONE Stinson has a midsole design, designed to cradle the foot, which may account for reduced peak lateral forces. Finally (or firstly), the abstract of the study does not indicate what attributes define a shoe as traditional or highly cushioned, so where can comparisons actually be made?
So at this point, the study doesn’t indicate anything of value. However, the study does bring to light that many factors must be considered when comparing shoes. I believe it is great that people are looking into the differences amongst different types of running shoes. We can only hope that future studies will better control for variables found within shoes. But with so many variables, we may never have the evidence necessary to draw generalizations about footwear types, which leads us back to: what shoe works for you?