The capacity oflaunching objects at high speed and with precision arose about two million years agoto facilitate the hunting of our ancestors, and was acrucial step in the evolutionary process of man, according to research just published by the magazineNature. In fact, humans are unique in their ability to throw when compared to other primates. “Although chimpanzees are incredibly strong and athletic, adult males of this species can only throw 20 miles per hour, which is about one-third the speed of a 12-year-old boy playing baseball on a ball.” , explains Neil Roach, a researcher at George Washington University (USA) and co-author of the work.
Using a three-dimensional video camera, Roach and his colleagues filmed several movies of baseball players in action and found thatthe human shoulder functions as a kind of slingshot, storing and releasing large amounts of energy. “The moment humans make a throw, we rotate the arm backwards, stretching tendons and ligaments that cross the shoulders and storing elastic energy”, explains the researcher. When we then release this energy, “the arm accelerates forward, generating the fastest movement the human body is capable of producing,” he adds. This is possible thanks to a series of anatomical changes (reduction and enlargement of the shoulders, expansion of the waist and torsion of the humerus) that allowed the first human beingshunt more efficiently, that is, by launching projectiles, which helped our ancestors include meat in their diet and paved the way for a series of later adaptations, such as increased brain size and emigration from Africa.
“If we weren’t good at throwing and running and some other things, our brains would not have evolved to larger sizes or cognitive abilities like language would have been developed. That is, if it weren’t for our ability to throw, we wouldn’t be what we are today. “, concludes Daniel Lieberman, a researcher at Harvard University and co-author of the study.
