Within six weeks, Cao was doing 180 pull-ups a session. Six weeks after that, he went from 180 to more than 600. Soon, Stanford’s football trainers asked to borrow a few Gloves to cool down players in the weight room and to fight muscle cramps.
In 2001, Heller went to Darpa. The agency saw the potential of the Glove for training recruits; the Stanford researchers received their first funding in 2003 and got $3 million.
In trying to figure out why the Glove worked so well, its inventors ended up challenging conventional scientific wisdom on fatigue. Muscles don’t wear out because they use up stored sugars, the researchers said. Instead, muscles tire because they get too hot, and sweating is just a backup cooling system for the lattices of blood vessels in the hands and feet. The Glove, in other words, overclocks the heat exchange system. “It’s like giving a Honda the radiator of a Mack truck,” Heller says. After four months of using it himself, Heller did 1,000 push-ups on his 60th birthday in April 2003. Soon after, troops from Special Operations Command were trying out the Glove, too.