NASA/JPL

The world's strongest man needn't worry about relinquishing his title to a robotic competitor anytime soon, a recent contest indicates. At a conference held by the International Society for Optical Engineers in San Diego on Monday, three robotic arms tested their might against a human opponent in arm wrestling matches, which the flesh-and-blood contestant won handily.

Yoseph Bar-Cohen of NASA's Jet Propulsion Laboratory in Pasadena, Calif., first proposed the idea of a robot-versus-person arm wrestling showdown in 1999 as a means to encourage research into artificial muscles, or electroactive polymers (EAP). Three different designs rose to Monday's challenge and took on 17-year-old high-school student Panna Felsen. A robotic arm manufactured by Environmental Robots Inc. (ERI) in New Mexico put up the best effort, surviving 26 seconds, whereas arms from Virginia Tech and the Swiss Federal Laboratories for Materials Testing and Research capitulated in under four seconds each.

EAPs change shape when either chemicals or an electric charge activates them. The three robot arms used in the challenge feature different types of the compounds. The Virginia Tech arm contains a chemically activated gel that responds to changes in pH by contracting like a human muscle does. The Swiss arm uses four groupings of electrically activated EAPs and the three-kilogram ERI arm is driven by two sets of artificial muscles made up of different electrically activated polymers. Despite the losses, just staging the competition was beneficial for the field, considering Bar-Cohen thought it would take two decades to become a reality when he first proposed it. Of course, whether the robot arms will ever rise to the ultimate challenge of beating a world champion arm wrestler remains to be seen.