Title: of their habitually unshod [Print this page] Author: Labi1994 Time: 2019-4-23 15:07 Title: of their habitually unshod Just before I left on a camping trip last week I received an email from Amby Burfoot pointing me to an abstract of a paper to be presented www.johanweststeijn.nl at the 2011 meeting of the International Society Nike Air VaporMax Mens of Biomechanics. The study, titled “Foot Strike Does Not Predict Loading Rates During Shod or Barefoot Running,” was conducted by a group of researchers from Oregon headed up by James Becker. Amby wrote up a post about the study on his Peak Performance blog, and included this line: “I have no doubt biomechanists with a different perspective will find much to dissect and debate with the Oregon team. That’s what Ph.D.’s do for fun, after all.” Well, as a Ph.D. with an interest in biomechanics, I’ll take the bait and have my fun.Basically, the researchers had 11 habitually shod subjects run across a force plate either in shoes or barefoot, and recorded the resulting ground reaction forces. In particular, they calculated vertical loading rate, which is essentially the speed at which Nike Air Max 90 Dames the foot initially impacts the ground. Loading rate is Adidas Superstar Femme of interest because some studies have suggested that it might be linked to a higher incidence of injuries like stress fractures. They also calculated a variable known as foot “strike index” (SI) for each individual – this is basically a value from zero to one that tells you at what point from heel to the tips of the toes the foot makes initial contact with the ground (a value of 0 would be far back on the heel, a value of 1 would be at the tips of the toes). Their goal was to determine if strike index was a good predictor of the vertical loading rate. In other words, does the location at which the foot makes initial contact with the ground influence the speed with which the collision occurs.The study concluded that stride index is not a good predictor of loading rate for either Nike Air Max 270 Mujer shod or barefoot runners, though the latter relationship was nearly significant with a p-value of 0.06 (a p-value of 0.05 or less is typically considered a significant result). The authors also pointed out that most of the runners adopted a midfoot strike when switching to barefoot, and that those who continued to heel strike when barefoot experienced an increase in vertical loading rate. The latter is this is why I don’t agree with Amby’s statement that “the University of Oregon team will report that their lab testing doesn’t support the notion that forefoot striking lessens the “instantaneous load rate” vs. rearfoot running.” What it shows is that rearfoot running in cushioned shoes doesn’t differ from midfoot/forefoot running when barefoot – those who continued to rearfoot strike when barefoot experienced increased loading (as Nike Air Max 95 Femme was also shown by Lieberman et al., 2010). In other words, shoes allow us to rearfoot strike with a loading rate similar to that seen when we forefoot strike when barefoot, and loading rates of both are lot less than if we were heel striking when barefoot.The study also failed to find a significant difference in vertical loading rate between the shod and unshod conditions, and indicated that this could be due to a large amount of inter-individual variation in response. I’d also suggest that having habitually shod runners abruptly switch to running barefoot also might be involved here, as Lieberman et al., 2010 indicated that a majority of their habitually unshod runners had lower loading rates than shod heel strikers when running barefoot (this despite the fact that the difference Nike Air Max 2017 Dames between the two groups was non-significant). In other Nike Air Vapormax Womens words, a learning process might be involved when it comes to barefoot running and reduction of impact (see this abstract from the same ISB meeting for more on this).My take is that this abstract seems to provide support for a number of observations that exist in the literature. In particular, Lieberman et al, 2010 also showed that heel striking in a cushioned shoe results in a vertical loading rate that does not differ from that of individuals who forefoot strike when barefoot (look at Figure 2b from their Nature paper). However, what does differ is the fact that limbs in the different conditions likely handle the impact loading in different ways.
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