The first world record in the men's 400 metres hurdles was recognised by the International Association of Athletics Federations in 1912.
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.
On August 3, 2021, Warholm broke his record again in the Tokyo Olympics 400 meter hurdle final.
Starting January 1, 1977, the IAAF required fully automatic timing to the hundredth of a second for these events.
[1] John Akii-Bua's 1972 Olympic gold medal run was the fastest recorded fully electronic 400 metre race to that time, at 47.82.