Saturday, September 24, 2011

Stiffness adaptations in shod running. (from the Gait Guys!)

Source : J Appl Biomech. 2005 Nov;21(4):311-21.
Physiology Laboratory, PPEH Unit, University of Saint-Etiene, France.
How long do you run in the shoes at the store before you decide whether they are a good match or feel for you ? This study suggests that if you take less than 4 minutes in a pair, you are not getting the accurate feel of the shoes.  Your “running stiffness” takes at least 4 minutes to adapt and alter to a given shoes materials.  Each shoe will likely feel different.  Don’t be fooled by the EVA’s softness, or the sock liner’s plushness. They might be there to offset what this study found, that being…… shoe stiffness increased significantly during the first 4 minutes but beyond the 4th minute, shoe properties remained stable.
How many stores or shoe companies are telling you this one !? 
Well, we are telling you right here and right now…….. first impressions are not always the best ones. 
  • “We don’t know where our first impressions come from or precisely what they mean, so we don’t always appreciate their fragility.”  - Malcom Gladwell
* Read the study’s conclusion below…… and think (and feel) before you buy. Read your favorite internet blogger’s shoe reviews with an educated eye, and an open mind.  What they feel and report could very likely be the exact opposite of what you feel because their anatomy and running style could be very different from your own.
We are, without a doubt…… from all angles…….. The Gait Guys


When mechanical parameters of running are measured, runners have to be accustomed to testing conditions. Nevertheless, habituated runners could still show slight evolutions of their patterns at the beginning of each new running bout. This study investigated runners’ stiffness adjustments during shoe and barefoot running and stiffness evolutions of shoes. Twenty-two runners performed two 4-minute bouts at 3.61 m.s-1 shod and barefootafter a 4-min warm-up period. Vertical and leg stiffness decreased during the shoe condition but remained stable in the barefoot condition, p < 0.001. Moreover, an impactor test showed that shoe stiffness increased significantly during the first 4 minutes, p < 0.001. Beyond the 4th minute, shoe properties remained stable. Even if runners were accustomed to the testing condition, as running pattern remained stable during barefootrunning, they adjusted their leg and vertical stiffness during shoe running. Moreover, as measurements were taken after a 4-min warm-up period, it could be assumed that shoe properties were stable. Then the stiffness adjustment observed during shoe running might be due to further habituations of the runners to the shod condition. To conclude, it makes sense to run at least 4 minutes before taking measurements in order to avoid runners’ stiffness alteration due to shoe property modifications. However, runners could still adapt to the shoe.