The first world record in the men's 400 metres hurdles was recognised by the International Association of Athletics Federations in 1912. That inaugural record was the performance by Charles Bacon at the 1908 Olympics.[1]
Three athletes, all from the United States, have had long-standing records. Glenn Hardin broke the world record three times and was the record holder for over 21 years, between 1932 and 1953. Edwin Moses set his first record in 1976 and improved his own world record three times. He held the record from 1976 until 1992, when it was beaten by Kevin Young with a time of 46.78 seconds at the 1992 Barcelona Olympics.
Young’s record stood for nearly 29 years, until Karsten Warholm broke it during the Diamond League event at his homefield of Bislett during Bislett games in 2021. The new world record was at 46.70. On August 3, 2021, Warholm broke his record again in the Tokyo Olympics 400 meter hurdle final. The world record is now 45.94.
As of June 21, 2009, 21 world records have been ratified by the IAAF in the event.[1]