Humans evolved for distance running – but ancestor ‘Lucy’ didn’t go far or fast

https://www.nature.com/articles/d41586-024-04194-4

By Gemma Conroy

Our ancient ancestor, Australopithecus afarensis—famously represented by “Lucy”—could walk upright and even run on two legs, but not with the speed or endurance of modern humans. Using 3D simulations of Lucy’s skeleton, scientists found that her smaller muscles and lack of an Achilles tendon limited her running speed to about 5 metres per second. By comparison, modern humans can reach about 8 metres per second. The study highlights how physical adaptations, like human-like ankle muscles and an efficient Achilles tendon, evolved to support long-distance running in our lineage. Understanding Lucy’s capabilities gives us a glimpse into how our ancestors gradually developed the traits that make us exceptional runners today.