"...What happened next was interesting. After the 4-week acclimation period, running economy in the Vibram Fivefingers increased dramatically (~8%), RPE decreased by 9.45%, and foot strike shifted more toward the forefoot. To a certain extent this is to be expected – as they acclimated to the novel footwear condition, the runners got more comfortable and more efficient at running in the barefoot-style shoes. However, more surprising is that in the post-test comparison the runners were now about 7% more economical in the VFFs than they were in the training shoes (the difference was statistically significant). They also tended to land more often on the forefoot in VFFs, and continued to run with a higher stride frequency in the VFFs compared to the training shoes. Economy in the training shoes improved by 2.32% after the 4-week period, but the improvement was not significant and the authors point out that this could simply be a normal training effect (i.e., 4 weeks of additional training would be expected to have some physiological benefit)...."Interesting, indeed. I don't find this to be suprising at all, as the primary energy storage/recovery structure in the lower leg is the Achilles tendon. If you heel-strike, you don't give the Achilles (and the arches in the foot) the opportunity to lengthen and capture energy. You're bypassing the "hybrid" nature of running: propulsion should be provided both my muscles and by the elastic properties of tendons and ligaments.
Read the whole thing, Pete does a nice job (as usual) tieing these results together with those of other studies that appear contradictory at first glance.
And Happy New Year!
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