http://www.nature.com/nature/journal/v463/n7280/full/nature08723.html

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.

http://www.npr.org/templates/story/story.php?storyId=123031997

Article

Mother Nature has outpaced science once again: the bare human foot
is better for running than one cushioned by sneakers. What about those $125
high-tech running shoes with 648 custom combinations? Toss 'em, according to a
new study published online January 27 in the journal Nature (Scientific American
is part of Nature Publishing Group).

http://barefootrunning.fas.harvard.edu/

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