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There is a lot more talk about barefoot running these days, thanks largely to the success of Chris McDougal’s book Born to Run. One of the heroes of that book is Daniel Lieberman, an evolutionary biologist at Harvard University whose work suggests that human beings evolved as runners. The basis of this argument is the fact that many of the physiological characteristics that make us different from other ape species (upright posture, large buttocks, etc.) make us much better long-distance runners than they are. Perhaps inspired by the attention that Born to Run has received, Lieberman and colleagues recently conducted a study designed to compare impact forces in barefoot runners (who run the “natural” way our ancestors did) and runners wearing modern running shoes (which have existed only since the 1970s).
A number of habitual barefoot runners were recruited to participate in the study. Lieberman’s team noted that most of them made contact with the ground on the forefoot, while some landed on the midfoot and a very few were heel strikers. By contrast, nearly all of the shoe-wearing runners who participated in the study were heel strikers. Impact forces during running were significantly lower in those barefoot runners who landed on the forefoot than in shod runners.
“This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground,” explained the authors in the published results, which appeared in the Jan. 28 edition of Nature. What this means is that in barefoot runners who land on the forefoot, the ankle joint plays a more active role in absorbing impact, so that less impact force reaches the shins, knees, pelvis and hips.
The practical implications of this finding are open to debate. While it seems to suggest that runners should run barefoot or switch to a forefoot footstrike or both, running experts disagree about the practicability of such changes, both of which can create new problems if made without due care. At this point it seems clear that shoe designs and the teaching of running technique will need to evolve in response to mounting evidence that conventional running shoe designs encourage “unnatural” stride patterns that increase injury risk. But we’re still a long way from having it all figured out.
Lieberman, D.E., M. Venkadesan, W.A. Werbel, A.I. Daoud, S. D’Andrea, I.S. Davis, R.O. Mang’eni, and Y. Pitsiladis. “Foot strike patterns and collision forces in habitually barefoot versus shod runners.” Nature. 2010 Jan 28; 463(7280):531-5.