With sleek, curved prosthetic legs that appear straight out of a sci-fi movie, sprinter Oscar Pistorius has been blazing across running tracks, leaving controversy in his wake.
At issue is whether those carbon graphite appendages give the 20-year-old South African bilateral amputee an advantage over able-bodied runners, an issue that's yet to be determined as he makes a bid for the 2008 Olympics in Beijing. No, say prosthetic manufacturers, other amputee athletes and researchers. Maybe, says the International Assn. of Athletic Federations, the governing body of world track and field, which continues to study the matter before making a ruling.
Although national Olympic committees ultimately select the competitors, technical rules in track and field are enforced by the IAAF. And one of its rules forbids "technical aids that give the competitor an advantage over someone not using them."
As prosthetics improve and training techniques advance, such cases are likely to become more common. Even as prosthetic designers try to devise limbs that would be an improvement over biological limbs, many of today's amputees are determined to be as fit and competitive as possible. In doing so, they're going up against the fittest of able-bodied athletes, regardless of the odds.
A little more than a week ago, Pistorius placed seventh at a race in England, running the 400 meters before being disqualified for going outside his lane. But he had already garnered attention for holding world records in the Paralympics. Although he's not the first disabled athlete to compete against able-bodied athletes, he is the first bilateral amputee who may make the crossover.
The prevailing sentiment among those who work with amputees is this: "I think he has a distinct disadvantage," says Hugh Herr, associate professor of media arts and sciences at MIT. A double amputee himself, Herr is director of the school's Biomechatronics Group. "The prosthetic he's using is completely passive -- it's just a spring." A spring, he adds, that can't possibly compare with the force with which the human leg can propel a foot off the ground. "That comes from the muscles, and he has no muscles," Herr says. "He's just really fast."
Amputee athletes must compensate for what they don't have -- muscles, tendons, ligaments, joints, bones -- things that even a state-of-the-art passive prosthetic can't re-create at this stage, researchers say. That compensation varies depending on whether a person is a single or double amputee, how much of the leg is left, and individual biomechanics.
