Thursday, August 2, 2007

Run, Oscar, Run!

The most famous amputee in the world right now is perhaps South African sprinter Oscar Pistorius. The Paralympic world record holder in the 100, 200, and 400 meter races is trying to qualify to represent his country in the 2008 Olympic Games in Beijing, China, but not without protest from the IAAF, which governs the Olympics. Some people worry that Pistorius' two prosthetic feet give him an unfair advantage over able-bodied athletes. Tests are now being done, and the outcome will determine if Oscar gets to compete against the most elite runners in the world or if he'll have to stick to racing against other amputees.

Oscar Pistorius doesn't have calves. His J-Shaped "Cheetas," passive prosthetic feet powered entirely by his quadriceps, mimic the spring of the human foot and achilles tendon. But whereas the spring in the our step can return over 200% of the energy we put into it, Pistorius' feet only return less than 95% energy, because he has no calves. One objection claims that Oscar's prostheses don't fill with lactic acid during a race like an able-bodied runner, but weakening calves still provide more energy than the best passive mechanical device. Other objections state that Pistorius' legs are more aerodynamic than human legs and don't use energy from his body. However, gait studies have always shown that below-the-knee amputees actually burn more calories and use more oxygen moving the same distance as able-bodied people. Again, the man has no calves! He's so slow exploding out the blocks that the second half of his lap is actually faster than his first.

The PowerFoot One prosthetic foot, recently manufactured by iWalk, actually incorporates computer processors and battery-powered motors to replace the function of the calf and achilles tendon. This and other bionic devises like Ossur's Power Knee promise to enhance the prosthetic industry, if their size, weight, and price can ever come down. When that day comes, that IAAF better watch out! But until then, there's no way that passive prosthetic feet like the ones Oscar Pistorius wears could give anyone an unfair advantage over sprinters with calves.

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