It looks like man did indeed need to learn how to walk before he could run, according to findings by British researchers.

The study by University of Manchester researchers, presented to the British Association for the Advancement of Science on Tuesday, confirms that early humans walked upright but also suggests they may have lacked an Achilles tendon — as modern chimps and gorillas do. If so, that would have seriously limited their ability to run.

“Our research supports the belief that the earliest humans used efficient bipedal walking rather than chimp-like ‘Groucho’ walking,” said Bill Sellers, who led the research in the University’s Faculty of Life Sciences, in  a release. "Our work suggests running effectiveness would be greatly reduced with top speeds halved and energy costs more than doubled."

The Achilles tendon is like a big spring that generates most of our running energy, Sellers said.

The researchers added that humans would have had to have developed the tendon — and thus the ability to run at full speeds — at some point in order to move from a plant-based diet to one that depended on hunting. When that may have happened is still a big question, Sellers said.

Sellers used the same computer modelling in the research as that in his recent charting of the running speeds of five dinosaurs. He used a humanoid bipedal computer model that incorporated data from a hominid fossil skeleton called "Lucy," as well as hominid footprints found preserved in ash in Tanzania.

"We have borrowed techniques from other scientific disciplines — robotics, computer science and biomechanics — in an attempt to ‘reverse engineer’ fossil skeletons," Sellers said. "This model is a virtual robot where we can activate muscles and get it to move its legs in a physically realistic fashion."

Sellers said that humans were walking upright up to 3.5 million years ago, although they probably would have done so much slower than we do today because they were smaller and shorter.