Achilles' heel 'was no evolutionary weak spot'

Published on Wednesday 12 September 2007 01:09

THE formation of an 'Achilles' heel' could, ironically, have been the defining moment in the development of mankind, researchers believe.

The Achilles tendon, which acts as a spring to store energy, allowed man to run with greater efficiency and speed, a Manchester University study found.

Dr Bill Sellers, who led the research at the university's faculty of life sciences, said: "

Walking upright seems to be the first thing that distinguishes our ancestors from other apes, so finding out about this should help us map the evolutionary path to modern humans.

"The next interesting question is to look in more detail at running."

Dr Sellers pointed out that modern chimpanzees and gorillas did not have an Achilles tendon.

He added: "If you have tendons you can go a lot faster and you use a lot less fuel - this seems to be the key. If you can find evidence of an Achilles tendon, then that will be the point that tells you when we actually started to run properly.

"This seems to be the thing that allows us to follow all those other things we do as humans.

"It changes your options, frees up the arms, makes hunting possible."

Dr Sellers, who recently published research on the running speeds of five meat-eating dinosaurs, used the same computer software to "make dead men walk".

His team used data from 'Lucy' - a hominid fossil estimated to be 3.5 million years old - and footprints preserved in ash at Laetoli in Tanzania, East Africa, to help generate a "virtual robot".

The simulation then learned which muscles to fire, and when, in order to walk properly, with minimum energy and maximum speed.

Presenting his research at the British Association Festival of Science at York, Dr Sellers said: "The skeletons and footprints from some of the earliest members of the human lineage - the early hominids - provide the best clues we have to how we progressed to modern human walking and running."

Dr Sellers also suggested that the Achilles tendon probably developed some time between two million and three and a half million years ago.