Do you remember the first time you ran? Was it early in life? Later? Somewhere in the middle? Did you bound out of the womb ready to clock your first personal best, or did you take to the track with a bit more hesitation? Did you do it because it was asked of you, as a P.E. requirement, perhaps? Or did you just feel it in your bones, a spring in your step ready to propel you into motion?
It might be easy for you to recall. (Or not, depending on how many other things you have on your mind in this fast-paced world.) But scientists at the University of Manchester in England are taking this question further back in time than any of us can remember (regardless of how clear our memories feel today!)—millions of years, in fact. They want to know when early humans were first able to run.
According to research presented at this year’s BA (British Association for the Advancement of Science) Festival of Science in York, England, it seems the ability to run, or at least to run efficiently, is tied to the two bits of us we call our Achilles tendons. And the researchers believe there’s a good chance we haven’t always had them.
Scientists, led by Dr. Bill Sellers, are using what they know about skeletons and muscles to build computer models that simulate bipedal walking and running motions. From these models, they can make suggestions about the motions and efficiencies of early hominin. They have built a model based on a 3.2 million year-old Australopithecus afarensis skeleton called “Lucy” and footprints preserved in ash by getting the “virtual robot” to move its legs in a “physically realistic fashion.”
According to Sellers, in a press release from the University of Manchester, “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.”
The initial findings suggest that the Achilles tendon—a storehouse of energy for the running motion—is important for efficient running. When they remove it from the model, the running speed is reduced. Without the Achilles tendon, the model can still walk, but it can not run quickly and it uses a lot more energy.
Though the researchers have hurdled issues behind getting the model to walk and run without tripping over its own feet, they are still left with the task of finding evidence of Achilles tendons in fossils. This is somewhat difficult, as scientists need intact ankle bones to examine, and most fossils don’t have them. However, if this evidence is found, it could be used to fill in missing pieces about when human predecessors developed the ability to run.
So today, as we stride and bound along the trail, let’s be thankful for our Achilles tendons. It seems they are doing way more for our running than we sometimes give them credit for.