Early Man's Achilles Heel

Though not mentioned directly in the epic Homer’s Illiad, the death of Achilles has brought with it one of the more involved etymological quips of modern day. It is said that Achilles mother, Thetis, dipped her baby in to the river Styx to make him invulnerable. His eventual downfall was as a result of the fact that she had gripped on to him by his heel, thus providing a fatal weak spot for the arrow that would later claim his life.
It was Paris who had poisoned and shot the arrow that took Achilles down, and subsequently provided us with the term for a human’s “only weakness” as well as for our Achilles tendon, a tendon of the posterior leg.

According to a study from researchers at the University of Manchester though, man’s first evolutionary steps from an ape may have been deprived of the ability to run.

Modern day chimps and gorillas lack an Achilles tendon, which forces them in to that four-limbed crouching run, or the “Groucho” walk. However research supports the belief that our first evolutionary ancestors used efficient bipedal walking, rather than the “Groucho”.

“But if, as seems likely, early humans lacked an Achilles tendon then whilst their ability to walk would be largely unaffected our work suggests running effectiveness would be greatly reduced with top speeds halved and energy costs more than doubled,” said Dr Bill Sellers, the man who led the research in the University’s Faculty of Life Sciences.

So what are the real facts behind this? No one is sure, but Sellers and his team are out to find out, using a multitude of sciences and skills in the process.

Borrowing techniques from robotics, computer science and biomechanics to reverse engineer fossil skeletons like the hominid fossil skeleton called ‘Lucy, combined with the computer software that Sellers used in his research on the running speeds of five meat-eating dinosaurs, the team have created a computer model that they hope will eventually provide answers to questions never before asked.

“This model is a virtual robot where we can activate muscles and get it to move its legs in a physically realistic fashion… if we use big enough computers and let the model fall over enough times it is possible for the simulation to learn which muscles to fire and when in order to get the model to walk properly.” This computer model was used to look at specific parts of the human body, including the Achilles tendon, which was essentially a giant spring able to store large amounts of energy during running. When the tendon was removed though, the running speed was greatly reduced.

That we evolved from the chimpanzees some six million years ago is a question that many scientists are safe in assuming is correct. Our first steps away from the chimp are, yes, steps! The upright walk! However the next step in their research is to find out when we began running, as well as how and when the Achilles tendon came in to play.

Posted by Josh Hill.

Story links:

http://www.physorg.com/news108717499.html
http://en.wikipedia.org/wiki/Achilles'_heel
http://en.wikipedia.org/wiki/Achilles_tendon