Matthew Herper, 10.15.07

Hugh Herr lost both his legs in a rock-climbing accident when he was 17. Now he plans to someday run faster than anyone ever has: on a pair of robotic legs.

Don’t bet against him. Six months after losing his legs, Herr was rock-climbing almost as well as before on prosthetics he modified himself. Now an associate professor at the MIT Media Laboratory, Herr designed the first robotic knee ever to make it to market–it’s sold by Iceland’s Ossur–and has just finished up the first replacement ankle that’s as strong as one of flesh and blood. It is only a matter of time, he says, before amputee athletes can routinely run faster and jump higher than Olympians.

Already, scientific advances may be driving the record books. Performance-enhancing drugs, including steroids for strength and EPO for endurance, are used in sports from cycling to baseball, with only draconian testing policies keeping them at bay. What happens if they became an accepted part of sports?

In Pictures: The Making Of A Super-Athlete

Tufts University physicist Roger Tobin, who has tried to put some numbers on the problem, says performance-enhancing drugs actually deliver less bang per dose than you’d expect from a relatively small increase in strength. At the highest levels of sport, it’s enough. “It could be the difference between the bronze medal and the gold, or the world record or not,” he says.

Tobin estimated that over a career, a baseball player using steroids could up his muscle mass by perhaps 10%. That would increase the speed of his bat by 4%, and the speed of the ball by 3%. For the top batters in the game, that tiny boost in power increases the number of balls hit out of the park by 50% to 100%. Given the potential side effects of these chemicals, we don’t want athletes using them. However, it’s no surprise they do.

Steroids are just the beginning. A drug being tested by Wyeth for muscular dystrophy blocks myostatin, a protein that prevents muscle from being created. Animals that use these same compounds grow incredibly large muscles, as did an infant with a mutated version of the myostatin gene. Already, dietary-supplement companies have been selling algae-derived medicines they say do the same thing–with no real evidence.

And a molecular switch inside cells called a peroxisome proliferator-activated receptor (PPAR) delta is involved in unknown ways with metabolism. “Marathon mice” that have had the PPAR delta receptor altered through genetic engineering can run for twice as long as their unmodified brothers and sisters. Drugs that turn up PPAR delta are in testing for the treatment of diabetes, but this has been a difficult area of drug development, because drugs to hit these mysterious receptors often have side effects.

The ultimate shift will come if science learns how to directly edit an athlete’s DNA, making him or her physically better without the need for drugs. So far, gene therapy, which aims to do this using modified viruses and other technology, has not panned out as a treatment. If it ever does, it could make the jobs of anti-doping associations far more difficult.

Replacement limbs that outperform real ones are far in the future, but some athletic associations are already worrying. Oscar Pistorius, a South African double-amputee and champion sprinter, has been fighting to compete against able-bodied athletes. But in July, the International Association of Athletics Federations, which is the arbiter at track-and-field events, said it needs “future research” to determine whether Pistorius, 21, has “advantages as a result of his prosthetic blades.”

The running prosthetics being developed in Herr’s lab don’t really have to be better than real legs, which need to be able to walk, climb and sit. They just need to be able to run, and they don’t need to be pretty either. Aimee Mullins, a double amputee who became a National Collegiate Athletic Association sprinter, told a recent Media Lab conference that at one point she wanted normal legs, but then she “got the bug. I wanted this stuff that came out of NASA.”

Herr wants to change the way people underestimate others who are different, and perhaps overestimate themselves. “Most people view the human as the center of the universe in terms of form and function,” he says. “They take something as basic as walking and running, and they have an amputee they pity and look down on run faster than they do … that’s mind-changing. That change in mindset about how people view others with different bodies is very important to society.”

That big change in mind-set could affect sports too. If human anatomy is no longer the center of the universe, would it be more fun to watch the athletes who can jump higher? Sure, it seems unlikely that people will have their legs replaced. But Herr’s lab is also working on exoskeletons that can help people carry 100 pounds without assistance. Someday, they might also allow athletes to traverse rough terrain–Herr predicts people will throw out their mountain bikes.

Imagine it: football games played on rocky mountainsides, or baseball with an obstacle course in the middle of the field. A skilled athlete would still do better than an unskilled one, but the exoskeletons would bring the game to an undreamed-of level. Says Herr: “It’s going to be fun as hell.”