Amputee Gets a Shot at the Olympics

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• 	able-bodied dvschack on 05/21/2008 at 10:10 AM
  Posts: 1 Avg Rating:	Since the argument is made that there is no advantage to using the Cheetah, I was wondering if able-bodied runners are allowed to use the same/similar devices in the Olympics as well. Rate this comment: (Reply)

• Handicapped and Negligent Scientists!? Artansoul on 05/21/2008 at 11:06 AM

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  Reading the article, I can't believe the negligent omissions in understanding what limits the speed of an athlete! Quite unimaginable ignorance. There are three things stopping an athlete travelling at unbelievable speeds, that would outpace ostriches, cheetahs and even fast cars! The weight of the athlete, working against gravity, the acceleration and deceleration of that weight and the wind resistance created when travelling forward, suggesting that the ratios of strength to weight, strength to mass of limb extremity and strength to frontal area of the limb is of paramount importance when considering this argument. I see no evidence that this has been looked at, yet this is the critical argument that need be considered. A runner who sprints at 27 mph must accelerate his lower legs to well over 54 mph with every stride, to compensate for the foot being stationary on the ground for a period of time with each stride. The work of acceleration and deceleration of the lower limb is resisted by the relative weight at the extremity, across the given speed range, effectively being far greater at higher speeds, 54+ mph and by the wind resistance, with energy requirements being squared as the speed doubles, as it does in this case. In cycling, reducing frontal area by having the cyclist reclining has seen speeds circa 70 mph, compared to the 40 mph conventionally seated. This is also the reason why the 'superman' position on the track was made illegal. I would like to point out also, that as a spring stores anergy for later release, the muscles around the ankle are doing actual work to absorb the shock of impact adding burden to the limitations of the cardiovascular system. This limiting factor for the speed of the runner with prosthetic limbs is removed, however, so is the burden of propulsion attributable from the lower limb. An advantage or disadvantage? Most drive comes from the muscles controlling hip and knee, but in what proportions to the lower limb it's difficult to say, but hardly what matters here to make a fair race. It's patently unfair to reduce your work load, by sizeable margins, by removing parts of your body, especially the fast moving, accelerating and decelerating, bits that have poor aerodynamics and yet keep the major propulsion engine relatively intact. The reduced resistance on the extremity of the limb also means that a longer prosthetic can be employed to increase leverage for the the drive coming from the upper legs, increasing stride length and reducing acceleration and deceleration cycles. If you want to asses athleticism, the loads on the cardiovascular system are going to be different for an amputee. Even taking the competition off the track and into the lab isn't going to create a fair and level playing field. Perhaps we can now get a biomechatronics specialist to argue that trucks and Formula 1 cars should compete together as there's no fundamental difference in there power output. Philip Grant Rate this comment: (Reply)