You shouldn't be allowed to compete with non-disabled competitors when you have a prosthetic limb(s). You no longer possess the same competitive physical nuances that come with having limbs. Essentially, it's not an even match-up; they are competing under different conditions.
I agree with "170366", Prosthetic limbs aren't being designed to be equal to the human leg ... They are being designed to be better in certain aspects. The picture, for example, is a man using a limb specifically engineered for the purpose of running. No normal human leg can boast that.
There are a ton of sports where an appendage could be made to be better than the human hand also. Imagine the world of shooting sports would be changed. What of a limb with a fin on it for swimming? You wouldn't let a guy with flippers race Michael Phelps ... It just wouldn't be fair. And I'm not sure you could get a board together to approve 100% that a particular appendage was equal for the purpose of Olympic competition either. Especially since the interface is different for each handicapped person. No two ways they'd leverage the appendage would be the same ... So they could not approve one without it being an advantage to a particular guy with the right measurements for it.
It's just a whole can of worms.