"Oscar sees no limits; he has no fear when competing against able-bodied athletes. So it is hard for people to understand and to accept when you start to talk about whether or not he may have the advantage."  Johnson, winner of the 200m gold in Atlanta 16 years ago and part of the 4x400 metres team who reigned in Barcelona, said that while 25-year-old Pistorius was unlikely to reach the Olympic final in the English capital, having recorded a personal best time of 45.07 seconds – the American's world record is 43.18 sec, which he achieved in the World Championships final in Seville in 1999 – he might be able to defeat some athletes who could become resentful of the fact.  The four-time 400m world champion continued: "Because his personal best is 45 seconds – and that is not enough to win medals – people generally will take the approach [that] he should be allowed to run, 'let him run, it’s great.'  "The issue here, and how it has to be approached, is that it has to be approached not taking in to account any particular athlete – so this has to not be about Oscar Pistorius.  "I consider Oscar a friend of mine, but he knows I am against him running, because this is not about Oscar; it’s not about him as an individual, it is about the rules you will make and put in place for the sport which will apply to anyone, and not just Oscar. If it was just about Oscar my position would be: ‘Absolutely, let him run.’"  Further, he set up a hypothetical situation where a top athlete – someone of Johnson's stature – suffered a serious injury and then turned to prosthetic limbs, and was then able to run even quicker times than previously achieved.  "[Team GB 400-metre runner] Roger Black made the best point on this whole thing," continued Johnson, "and said: ‘What happens when we have a Michael Johnson, a 43-second 400-metre runner, who then has a horrific accident and then becomes a disabled athlete and then you put him on blades, these prosthetics, and he is now running 41 seconds?"  "Actually that sounds pretty good, when I think about it," he joked, before adding: "Taking all that in to account and let’s say that [Pistorius] does have an advantage, when he shows up here in London in all likelihood he would not medal; he probably would not make it to the final.  "But for some athletes that he is going to be competing against who are able-bodied athletes who don’t have the advantage of having their prosthetic [limbs] and [not] needing to worry at all about their lower limbs, maybe he beats one of those athletes and he gets in to the semi-final and they don’t. The semi-final is an accomplishment for some of the athletes who will be competing here."
The 400-metre world record holder, Michael Johnson, believes disabled athletes   who use prosthetic limbs should not be allowed to compete in able-bodied   races, as it has not been disproved whether or not it provides them with an "unfair   advantage".