Humans born to run

It's official, humans were born to run long distances!

According to a theory proposed in the journal Nature by two American scientists, distance running played a crucial role in human evolution.

While walking upright first set human ancestors apart from their ape-like cousins, it may have been the ability to run long distances that influenced the evolution to today's human form. The evolution of a physique built for long-distance running is actually what made humans look the way we do now.

Endurance running, unique to humans among primates and uncommon in all mammals, other than dogs, horses and hyenas, apparently evolved at least two million years ago and probably enabled human ancestors to hunt and scavenge for food over large distances.

That probably proved decisive in their pursuit of high-protein food for development of larger brains.

The two scientists, Dennis Bramble and Daniel Lieberman, reported that their analysis of the fossil record showed striking anatomical evidence for the capability of prolonged running in the Homo genus as early as two million years ago.

By two million years ago early species of the Homo family, beginning at least with Homo erectus, had long, slender legs for greater strides.

They had shorter arms and a narrower ribcage and pelvis.

Their skulls included features to help prevent overheating. A ligament attached to the skull kept their heads steady as they ran. Traces of muscle and tendon attachment points on bones of early species revealed an extensive network of springy tendons which served to store and release elastic energy during running.

Such tendons were not needed for the ordinary walking of earlier hominids. And there was the gluteus maximus, the muscle of the buttocks.

Earlier human ancestors, like chimpanzees today, do not have the strong buttocks of humans.

As Dr Lieberman explained: "Your gluteus maximus stabilises your trunk as you lean forward in a run. A run is like a controlled fall, and the buttocks help to control it."

In such ancestors as the Australopithecus genus, famous for the 3.2 million-year-old Lucy skeleton, the physical characteristics favouring running were either absent or underdeveloped.

Somehow, the scientists continued, those early ancestors who developed primitive running qualities must have improved their chances of survival and reproduction.

Their ability to run greater distances than other predators must have been an advantage in making a kill or at least scavenging the kills of their swifter rivals.

The bottom line?

The physiological adaptations that the human body undergoes when performing regular endurance training amply demonstrate the existence of latent capability in all of us. It's no accident that just about every single healthy human can improve their exercise ability with a regular programme of aerobic training.

So when you go out on your regular training run, you are not teaching your body (unnatural) new tricks, but breathing new life into an ages-old ability that is part of the definition of what it means to be human.