Pitchers tell evolution’s story

Nature draws an ancient lesson from America’s favorite pastime, observing how baseball pitchers reveal the evolution of human beings:

“Throwing projectiles probably enabled our ancestors to effectively and safely kill big game,” says Neil Roach, a biological anthropologist at George Washington University in Washington DC, who led the work. Eating more calorie-rich meat and fat would have helped early hominins’ brains and bodies to grow, enabling our ancestors to expand into new regions of the world, he suggests.

Although some primates occasionally throw objects, and with a fair degree of accuracy, only humans can routinely hurl projectiles with both speed and accuracy, says Roach.

The researchers used high-speed motion-capture cameras to record the throwing motions of 20 college athletes, including 16 baseball players. They then handicapped the athletes’ throwing abilities to that thought to be more similar to that of our ancestral hominins, using therapeutic braces to constrain the range of motion in their throwing arms. The researchers could do this by simulating the shape and configuration of the joints of hominins known from the fossil record.

Their analyses suggest that shoulder muscles produce no more than half of the power generated during a throwing motion. Much of the remaining power comes from evolutionarily novel features in the shoulder and elsewhere in the body that temporarily store energy and then rapidly release it, the researchers contend.

It started 2 million years ago with Homo erectus, the first pitcher.