My son called earlier today, and we ended up talking about the Bladerunner. I suggested he had a weight advantage. My son said that amputees themselves recognize that, and want different categories for single and double amps. I couldn't find anything on google, but there is a study. showing a difference between flesh and "bionic". I suspect there are also cardiovasculular differences, in that there are fewer miles of blood vessels to perfuse, and fewer cells pumping out lactic acid.
In 2000, Weyand and a team of researchers at Harvard published a study showing that humans, from couch potatoes to pro sprinters, have essentially the same leg-swing times when they achieve their maximum speed. Says Weyand, "The line we use around the lab is, From Usain Bolt to Grandma, they reposition their limbs in virtually the same amount of time."
But Pistorius's leg-swing times, when measured on a high-speed treadmill, were off the human charts. At top speed, he swings his legs between strides in 0.284 of a second, which is 20 percent faster than intact-limbed sprinters with the same top speed. "His limbs are 20 percent lighter," Weyand says, "and he swings them 20 percent faster."
This is important because it allows Pistorius to circumvent a main requirement of top level sprinting: putting high forces into the ground quickly. Because Pistorius can make up time with his rapid leg swing, he can leave his foot in contact with the ground longer than other sprinters. To attain the same speed, Pistorius applies lower forces -- about 20 percent lower -- over a longer time, instead of higher forces over a briefer time. In this he's like a cross-country skier, whose boot has a hinge at the toe that allows him to leave the ski down and continue to push, prolonging the time he can continue to apply force.
Read more: http://sportsillustrated.cnn.com/2012/olympics/2012/writers/david_epstein/08/03/oscar-pistorius-london-olympics/index.html#ixzz22t8p2x8m |
