Daegu - South African double amputee Oscar Pistorius will have to run the first leg for his country should he wish to take part in the 4x400m relay at the World Championships, the IAAF said on Friday.
The athletics world governing body said that to "avoid danger" to other runners, Pistorius would run the first leg in his lane before handing over the baton to the second runner, who then breaks the lane order.
"This person is a particular case," IAAF head Lamine Diack said of Pistorius, who runs with carbon fibre prosthetic running blades in place of his lower legs, which were amputated at the age of 11 months.
"It is very rare that a person like him runs and he has taken part in several sports.
"We decided to let him take part in the world championships and we will see what the result will be.
"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."
Pistorius, known as 'Blade Runner', will make history in Daegu when he becomes the first amputee athlete to compete at the World Athletics Championships, one step towards running at the 2012 London Olympics.
Cleared three years ago to run against able-bodied athletes, the 24-year-old four-time Paralympic gold medallist left it late to qualify for the team, going under the requisite time at his final chance with a personal best of 45.07 seconds which also gives him the green light for the London Games.
Johannesburg-born Pistorius had both legs amputated below the knee when he was a baby because of a congenital condition that meant he was born without fibulae - lower leg bones.
Pistorius failed to qualify for the 400m at the 2008 Beijing Olympics having been given the green light to attempt to qualify after the Court of Arbitration for Sport overturned a ruling by the IAAF that his blades gave him an unfair advantage.