Was ability to run early man's Achilles heel?

Sep 11, 2007

The earliest humans almost certainly walked upright on two legs but may have struggled to run at even half the speed of modern man, new research suggests.

The University of Manchester study – presented to the BA (British Association for the Advancement of Science) Festival of Science in York on Tuesday – proposes that if early humans lacked an Achilles tendon, as modern chimps and gorillas do, then their ability to run would have been severely compromised.

“Our research supports the belief that the earliest humans used efficient bipedal walking rather than chimp-like ‘Groucho’ walking,” said Dr Bill Sellers, who led the research in the University’s Faculty of Life Sciences.

“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.

“Efficient running would have been essential to allow our ancestors to move from a largely herbivorous diet to the much more familiar hunting activities associated with later humans. What we need to discover now is when in our evolution did we develop an Achilles tendon as knowing this will help unravel the mystery of our origins.”

Dr Sellers, who recently published research on the running speeds of five meat-eating dinosaurs, used the same computer software to generate a humanoid bipedal computer model using data from a hominid fossil skeleton called ‘Lucy’ and hominid footprints preserved in ash at Laetoli in Tanzania.

“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 down the pathway to modern human walking and running,” said Dr Sellers.

“We have borrowed techniques from other scientific disciplines - robotics, computer science and biomechanics - in an attempt to ‘reverse engineer’ fossil skeletons; we use what we know about skeletons and the muscles to build a computer model of the fossil species we are interested in.

“This model is a virtual robot where we can activate muscles and get it to move its legs in a physically realistic fashion; the tricky bit is getting it to actually walk or run without falling over.

“However, 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. Even better we can ask the computer to find ways of minimising fuel cost and maximising top speed since that is what we think animals have to do.”

Dr Sellers initially looked at walking and his models suggested that even as early as 3.5 million years ago our human ancestors were able to walk as efficiently as modern humans. His research also showed that they preferred to walk a little slower than we do but only because they were much smaller and had quite short legs.

The team also used the computer model to look at particular parts of the human locomotion system, including the Achilles tendon, which they showed acts like a big spring to store energy during running; when the tendon was removed from the model the top running speed was greatly reduced.

“We have only just started to look at running and so there are still plenty of questions to answer,” said Dr Sellers. “But whilst these very early fossils could walk well, our initial findings suggest that efficient running came about quite a bit later in the fossil record.

“How we evolved from our common ancestor with chimpanzees six million years ago is a fundamental question. Walking upright seems to be the very first thing that distinguishes our ancestors from other apes, so finding out about this should help us map the evolutionary pathway to modern humans.

“The next really interesting question is to look in more detail at running. It has been suggested that our ability to run for long distances took a lot longer to evolve than our ability to walk and that this is a defining feature of our very close relatives in our genus. Our techniques should let us get to the bottom of this question because it will let us measure the running abilities of our fossil ancestors directly.”

Source: University of Manchester

Explore further: Free the seed: OSSI nurtures growing plants without patent barriers

add to favorites email to friend print save as pdf

Related Stories

Congress clashes over online domain name oversight

Apr 10, 2014

Republican opposition to Obama administration plans to spin off U.S. oversight of the Internet's domain name system is evolving into an election-year political fight, with lawmakers using it as the latest front in their attacks ...

Kinesin-5 structure opens cancer drug targets

Apr 08, 2014

The structure of a key part of the machinery that allows cells to divide has been identified by researchers at the University of California, Davis—opening new possibilities for throwing a wrench in the machine and blocking ...

Save money and energy by replacing, adjusting home appliances

Mar 26, 2014

Want to save some money and help the planet at the same time? Then take a look at some of the gadgets and appliances in your house. By turning off, adjusting or swapping out some of the devices in your house, you can potentially ...

Recommended for you

Plants with dormant seeds give rise to more species

15 hours ago

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Researchers successfully clone adult human stem cells

18 hours ago

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.