By Bruce Bower
Stone Age people, unlike their Neandertal contemporaries, had heel bones spring-loaded for long runs, a new study suggests.
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Neandertals weren’t left in the dust, though. The backs of their feet gave them a leg up on power walking, say anthropologist David Raichlen of the University of Arizona in Tucson and his colleagues.
In ancient Homo sapiens, as in people today, a short lower heel stretched the Achilles tendon taut, Raichlen’s team concludes. That arrangement increased the tendon’s spring-like action during running and reduced energy consumption, enabling extended excursions, the scientists report in a paper published online January 26 in the Journal of Human Evolution.