Double amputee Oscar Pistorius must run the first leg for South Africa if he is to take part in the 4x400m relay at the World Championships, athletics governing body said Friday.“This person is a particular case,” IAAF head Lamine Diack said of the athlete who runs with carbon fibre prosthetic blades in place of his lower legs, which were amputated before he was a year old due to a congenital condition.“The only thing we said to the South African federation is that if he wants to run in the relay, he must run the first leg to avoid danger to other athletes.” The 24-year-old, who will become the first double amputee athlete to compete at the world championships, said he would be proud just to be picked for the relay team and would run whichever leg team management told him to. “We haven't confirmed the positions of the relay, or if I'm even in the relay,” Pistorius told reporters, adding that he knew which positions made the “best sense”. “If I get any opportunity to run in the relay I'll be proud just to do that.”