Hugh Herr at BIF-2

If necessity, as they say, is the mother of invention, necessity was particularly cruel in Hugh Herr's case.

A rock-climbing prodigy as a youth in Lancaster, Penn., Herr suffered severe frostbite in an accident on Mt. Washington when he was 17. Both of his legs had to be amputated below the knee.

For a youth who had put all his energies into climbing—going to upstate New York every weekend, traveling around the country every summer in search of challenging ascents—it was devastating. His doctor told Herr he'd never climb again.

Until then, Herr had been an apathetic student, focusing on machine shop because it left him more time to climb. Now that experience came in handy.

"When I first got artificial legs they were painful and inflexible, so I started tinkering," he says. "I had learned in shop about how to build things, so I just started machining away and developed something."

Ultimately he developed special prosthetic legs that allowed him to climb at a higher level than he had with his natural limbs.

"I developed feet that allowed me to stand on rock ledges the width of a dime, and allowed me to wedge into rock fissures that even the human foot can't penetrate," Herr says. He also developed special feet for climbing ice faces, as well as legs whose height he could adjust if it helped to be taller for a particular rock face, or shorter for another.

"The experience was eye-opening and inspirational," he says—and, after he buckled down in school and developed a passion for science and math, it set him on his career path.

Now 41, Herr is an assistant professor at MIT and the MIT-Harvard Division of Health Sciences and Technology, and director of the Biomechatronics Group at the MIT Media Lab. His research team studies motion science and the biomechanics of human movement and balance, seeking to advance technologies that can accelerate the merging of body and machine.

Some technologies Herr works on are for human rehabilitation, to help people who have suffered amputations or limb pathologies. For example, Herr and a partner developed a prosthetic knee that is computer-controlled, allowing finer control and more natural movement. They're also working on machines called 'bio-hybrids,' surgical implants that will allow an amputee to directly control the artificial leg by thinking and contracting muscles.

Other technologies are for human augmentation, to make a healthy body better and stronger. For example, Herr's biomechatronic group has invented an exoskeleton that transfers most of any weight being carried to a set of artificial legs, rather than to the person wearing them.

"This could have applications in the military, firefighting, hiking—any activity where you're carrying a load," he says.

He's also working on a device that, instead of carrying a load for a person, will carry the person himself, perhaps through an interface to the person's pelvis.

"You can view it as a new form of mobility, a new transportation device," he says. "Imagine that instead of going to a bike rack you go to a leg rack, and you can run wherever your legs can take you, but you don't have to breathe hard."

If that sounds like the stuff of science fiction, keep in mind that Herr is working at a time when critical technologies involved in rehabilitation—such as robotics, machine learning and tissue engineering—are maturing enough to enable real breakthroughs.

"We're now at the point of history where if we just integrate these disciplines we can really see an unprecedented level of innovation over the next 10 years," he says.

Geopolitical realities also come into play.

"The war on terrorism has unleashed a tremendous amount of funding for this area," Herr says. "If you plot innovation in prosthetics over time, spikes of activity always occur after war: After World War II there was a huge spike, with all these young kids coming back with missing limbs. Now, soldiers are coming back missing limbs too."

If their doctors tell those soldiers they'll never be able to move well again, Herr recommends they get a second opinion. Another word of advice: Keep an eye on whatever Herr is tinkering with lately in his lab.