The head of the top international athletics body said Friday that Oscar Pistorius, the amputee runner from South Africa, must run in the first leg in the relay at the upcoming world championships here to prevent clashes, giving the latest twist to the dispute over Pistorius' artificial limbs. "We told the South African federation that if you want to have him (Pistorius) in the relays, he must run in the first leg," said Lamine Diack, president of the International Association of Athletics Federations (IAAF), through an interpreter at a press conference here. He was speaking after a joint meeting of the IAAF and the International Olympic Committee (IOC) on the eve of the 13th World Championships in Athletics.