primary joint motions of underhand throw

Sending Modern Baseball Players Back in Time The rotation of the humerus is the fastest motion the human body produces, said Roach, at over 9,000 degrees per second. New law could mark end of American Confederacy – in Brazil 'That allows us to essentially use the arm like a catapult, to store energy as we cock our arm or rotate our arm away from the target before we rapidly rotate it toward the target.' 'That change in the shoulder really brings all of those things together and that didn't happen until 2 million years ago,' said Roach. While chimpanzee shoulders sit very high and close to the neck, almost as if the animal is permanently shrugging its shoulders, human shoulders are much more relaxed. The change to the shoulder is crucial, explained Neil Roach, a biological anthropologist at George Washington University in Washington, D.C. Each trait has 'a major role in storing and releasing elastic energy during throwing,' the researchers wrote. Each feature allows the body to store more energy before a quick rotation that releases it: tall and mobile waists that permit torso rotation the way the elbow and the bone in the upper arm, the humerus, join together and rotate and the placement of the shoulders. Throwing projectiles fast and with high accuracy requires coordination, and also the anatomical features that first appeared together in Homo erectus.Ī team of researchers, reporting in Nature, found that the three key traits can be found in humans, but not our closest relatives, chimpanzees. The motion that launches a throw begins with the legs, moves through the hips, torso, shoulder, and through the arm to the hand. Making a strong, accurate throw requires the different parts of the body to work together in what biomechanics researchers call a kinetic chain - the rapid and sequential activation of different muscles. Researchers say they traced that ability back to three changes to the waist, shoulder and upper arm that happened about 2 million years ago in the early human Homo erectus.

However, not every close human relative has that ability to throw, despite the great strength that many possess. It's completely ordinary to see today's athletes throw a javelin hundreds of feet in the air or fire baseballs accurately and in excess of 90 mph dozens of times during a game.

Primary joint motions of underhand throw