In the annals of organized arm wrestling, there had never been a match like this. Ever since 1952, when the first official arm-wrestling competition took place at Gilardi´s Saloon in Petaluma, California, contestants have generally been large men with unusually muscular forearms. But on this Monday afternoon, the TV cameras focus on a slim 17-year-old girl.

In 1999, Yoseph Bar-Cohen of NASA's Jet Propulsion Laboratory challenged the engineering world to an arm-wrestling contest. Sort of, anyway. He doesn't plan on participating himself, and the arm, which will face off against a human opponent of middling strength, has to be robotic. The catch is, he's not asking for your standard metallic appendagethis robotic arm must be built with electroactive polymers (EAPs).