Johnson was plagued by injury in 1999, and his following season was troubled with two injury scares that limited him to just four 400 m races before the 1999 World Championships in Seville. Were it not for the IAAF policy established two years earlier for Johnson, that allowed automatic entry to defending champions, he could not have raced in Seville since he failed to compete in the U.S. trials due to his injury. He recovered and won his fourth 400 metre world title with a new world-record time of 43.18 seconds at the relatively late age of 31 years and 11 months, which stood for nearly 17 years before being beaten at the 2016 Olympics by the South African Wayde van Niekerk. Johnson's splits for this world record were 21.22 seconds for the opening 200 metres and 21.96 seconds for the closing 200 metres, giving a differential of 0.74 seconds.