Humans may not run faster than a cheetah or swim better than a shark, but
they out-throw other species, experts say. And the reasons for that may lie far
back in evolution.
People's ability to throw balls and other objects fast and accurately is a
trait that developed nearly 2 million years ago to help our now-extinct
ancestors hunt with rocks and sharpened wooden spears, new research
"We think that throwing was probably most important early on in terms of
hunting behaviour, enabling our ancestors to effectively and safely kill big
game," study lead author Neil Roach, of George Washington University, said in a
university news release.
"Eating more calorie-rich meat and fat would have allowed our ancestors to
grow larger brains and bodies and expand into new regions of the world -- all of
which helped make us who we are today."
Unique to humans
Superior throwing skills are unique to humans, the researchers noted, and
even our chimpanzee cousins can't come close to matching us.
"Chimpanzees are incredibly strong and athletic, yet adult male chimps can
only throw about 20 miles per hour -- one-third the speed of a 12-year-old little
league pitcher," Roach said.
He and his colleagues used a 3-D camera system to record the throwing motions
of collegiate baseball players. They found that the shoulder acts much like a
slingshot during a throw, storing and releasing large amounts of energy.
"When humans throw, we first rotate our arms backwards away from the target.
It is during this 'arm-cocking' phase that humans stretch the tendons and
ligaments crossing their shoulder and store elastic energy," Roach
"When this energy is released, it accelerates the arm forward, generating the
fastest motion the human body produces, resulting in a very fast throw."
The researchers also found that certain structural features in the torso,
shoulder and arm make this energy storage possible.
The findings may have important implications for athletes. For example,
baseball pitchers throw much more often than our ancient ancestors did.
"At the end of the day, despite the fact that we evolved to throw, when we
overuse this ability it can end up injuring us," said Roach, a postdoctoral
scientist in the university's Center for the Advanced Study of Hominid
The American Academy of Orthopaedic Surgeons discusses throwing-related
elbow injuries in children.