But perhaps most importantly, by keeping advances off the field, we're holding back possibilities. A few years ago I visited Hugh Herr, the director of biomechatronics at MIT's Media Lab, who had just invented a robotic ankle that would soon revolutionize prosthetics. We ended up discussing the ankle a little bit, but mostly we talked about science in sports. Herr is an athlete. As a young man he was a world-class rock climber. A week before my visit, he had been busy trying to convince the International Association of Athletics Federations to allow South African runner Oscar Pistorius to compete in the Olympics. Pistorius has no legs below his knees and runs using Cheetah Flex-Foot carbon fiber limbs which, arguably, gives him an unfair advantage. Herr is also a double amputee, and walks and climbs using prosthetics. That day in his lab, while he showed me his improved ankle and described his work with veterans, Herr told me that he sees no reason why we can't make "disabled" people stronger and faster than the rest of us. In fact, we already are: just look at Pistorius. The IAAF agreed and, weeks later, decided to ban the South African from competition.