I read an article that summarized competing "scientific" analysis results of the dynamics.
On one side opposing his participation, they say that the springs weigh less than regular lower legs so his hip flexors can generate a faster turnover with less effort. Also, the springs can be tuned to an average power output during the race based on his strength on any particular day, so he can wear the most efficient legs every time he races. That way every single time his "foot" hits the ground, it compresses and rebounds at the exact RATE as well as returning the input energy. Play with a slinky to see what I'm talking about... It takes 10 times the energy to start a spring oscillating but once it gets into a stable cycle, it takes very little energy to continue oscillating. So he can wear springs tuned to his weight, strength, optimum stride length and step rate. Other athletes must do this by coordinating the efforts of 20-30 muscles that fatigue unevenly.
On the opposite side, the company, backed up by independent analysis, claims that the springs can consistently return 90% of the input energy, just as claimed by the opposition study. But this other study says that a person with regular legs can get an over 200% return on energy imparted above the knee, through coordinated muscle inputs as the foot, tendons, bones, etc. flex through the running cycle.
Me, I lean a bit towards the opposition position simply because I have seen how a normal person can make HUGE jumps and leaps when wearing spring shoes or even just hopping on a pogo-stick. The ability to get in-sync with the spring rebound can I think give a large mechanical advantage, to the point where this runner is really running on reversed-joint lower legs and getting the same mechanical advantage a kangaroo gets when jumping.
Still, in this case I do not think his advantage is enough to use him as a single data point to determine whether or not he can participate. I figure let him run and re-address the issue after more data points have been gathered. Yea I suppose some athletes may feel unfairly put upon if some guy with spring legs beats them, but in reality there are at most 3 people who lose if Pistorius wins a medal, those who would have otherwise gotten one higher medal. Everyone else is just griping and moaning about something that could have theoretically been unfair. Only those who medal behind him or the one guy in 4th who would have gotten bronze had he not raced, are actually put out at all. I'm not convinced that making those people feel better about their finish is reason enough to prevent Pistorius from competing.
If it turns out later on that either Pistorius or other athletes with similar prosthetics end up consistently faster than un-modified runners, then they can always go back and asterisk all the amputee athletes' results and bump up the place of everyone else in those races. I'm not sure it's going to ever come to that though. Walking on springs instead of lower legs is HARD and I simply don't think we will see world records being beat by amputees wearing unpowered spring prosthetics.
