Tuesday, May 15, 2007

Sprinter in the Shell?

Bill and I are both fans of the Japanese animation movie and series Ghost in the Shell, whose central character, Major Motoko Kusanagi is "full cyborg"--a human being who, due to an illness or injury in childhood, has had her natural body replaced by a robotic body.

It's not a bad deal. She can leap tall buildings in just a few bounds, then dive off the roof and land without harm; lift objects weighing several tons and turn invisible at will using "thermoptic camouflage." Her superior physical abilities (and steely personality) put her squarely in the leadership of her elite security team, whose other members must struggle along with varying degrees of natural bodies.

In this, and other ways, the series poses the question: Where does human end and machine begin?

Now, the Olympics is posing the same question with regard to South African sprinter Oscar Pistorius, who was born with deformed legs that were amputated in infancy. But he can run--fast--on his cool-looking J-shaped feet. He runs 100 meters in less than 11 seconds and 400 meters in less than 47, good enough for second place against able-bodied sprinters at South Africa's national championships. Now he wants to go the Olympics, but the IAAF. (International Association of Athletics Federations) isn't so sure it should let him.

“With all due respect, we cannot accept something that provides advantages,” says Elio Locatelli, director of development. “It affects the purity of sport. Next will be another device where people can fly with something on their back.”

That's exactly the point Bill made when I debated this issue with him (and as the father of a very able woman who happens to have deformed arms and legs, he's more familiar than the average guy with prosthetics and what "differently abled" really means). Where do you draw the line? Can someone who's had laser surgery to enhance eyesight (as some Major League pitchers have) compete? Can a woman who's had a sex-change operation and was formerly male compete as a woman? (Yes, since 2004.) Can a wheelchair user run the marathon? (No, because it's obviously easier and faster to roll for 26 miles than run.) It makes for an interesting philosophical debate.

The thing is this, our assumptions about how prosthetics help a sprinter run may be completely wrong. And instead of taking the Geek Gap view--the technology-is-mysterious-and-magical view, it might be worth asking what the actual difference is between running on legs and running on prosthetics.

When you see Pistorius with his sprinting prosthetics on, they look like they would provide an unfair advantage in terms of springiness, allowing him to bounce--boing! boing! boing!--down the track way ahead of the runners with natural feet. But in fact, according to one expert, a human foot returns up to 240 percent of the energy absorbed in each stride, while a prosthetic leg returns only 80 percent (and the runner must make up the difference by working his hips harder).

Indeed, springiness is not the IAAF's objection to the prosthetics--height is. With the prosthetics on, Pistorius stands 6 feet 1 1/4 inches tall, and IAAF officials fear this height gives him an unnaturally long stride. Pistorius says it's within an acceptable range based on the length of his thighs. Again, as far as pictures go it doesn't look like the prosthetics make him unnaturally tall, but that's hardly a scientific measure, and it seems to me with all our forensic science and everything we can infer about a full being (whether mummy or dinosaur) by measuring one or two of its bones, it should be possible to figure out what height Pistorius would have been without the deformities.

But if you look at it that way, then a logical answer is obvious: of course he can compete in the Olympics. The question should be not whether he can compete, only how long a prosthetic he can wear.