Discussion: "Foot strike patterns and collision forces in habitually barefoot versus shod runners"
Published in Nature 2009: http://www.ncbi.nlm.nih.gov/pubmed/20111000
Here is one of the more interesting, albeit controversial, articles in recent publication. This article does a present a very supporting argument for the belief of barefoot running. Article abstract:
Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes. We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe. Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. 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. Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.
A very unassuming abstract, but it was received with very mixed responses. Some of these findings are, in themselves, self-validating. However, many believe that a much more hefty study base would be needed to make larger conclusions. Improvements, such as population size and variety of experience and shoe exposure.
As a means of hedging these antagonistic sentiments, he and several other of the Harvard researchers put together a brief and informative explanation at http://www.barefootrunning.fas.harvard.edu/index.html.
I would have little, if anything, to add to this explanation. I think its worth a read for any inquiring enthusiast. What is depicted to some degree by Lieberman et al, through these works, is the comparison of the stance phase of running in barefoot vs shod runners. Particularly forefoot vs rearfoot strikers (midfoot is somewhat intermediate between the two profiles).