Debate over advent of humans’ throwing ability stirred by video analysis

Science News : Unlike other primates, humans are able to throw objects with great accuracy at very high speeds. To determine the mechanics involved, Neil Roach of George Washington University in Washington, DC, and his colleagues used a 3D camera system to film a group of college athletes throwing baseballs. Computer analysis of the videos revealed that for fast throws, the shoulder appears to store and release energy in a manner similar to a slingshot. Roach’s team believes that this slingshot-like ability comes from a combination of factors that they say first appeared in Homo erectus 2 million years ago: A wider waist created a more flexible torso; realigned elbows increased energy storage in cocked arms; and broad shoulders increased the power capacity of shoulder and chest muscles. However, Susan Larson of Stony Brook University in New York says that no tendons in the shoulder are used for energy storage in the manner the video analysis suggests. She also says that the estimates of Homo erectus bone structure are inaccurate because they are based on partial fossils, and that other required characteristics weren’t actually present in the species. She believes that modern throwing ability first appeared much later, some 1 million years ago, in European hominids known as Homo antecessor and Homo heidelbergensis.