47.60 by Marita Koch.
Allyson Felix holds the WR of the 200m and the 400m
Cathy Freeman did not set any world records in the Olympics. She is remembered for winning the gold medal in the women's 400m event at the 2000 Sydney Olympics.
As of October 2023, the men's 400m world record is held by Wayde van Niekerk of South Africa, who set the record at 43.03 seconds during the 2016 Rio Olympics. The women's 400m world record is held by Marita Koch of East Germany, with a time of 47.60 seconds, set in 1985. Both records remain significant benchmarks in the sport of athletics.
Chewbacca
World Record 400m Individual Medley Michael Phelps (USA) August 9, 2008 Time: 4:03.84
11.28 100m, 23.37 200m, 54.75 400m national records still holds the national junior records in 200 and 400m dash http://pinoyathletics.com/2012/07/18/lydia-de-vega-mercado-legends-of-track-and-field-rev3/
That is Michael Johnson of the United States.
Ian Thorpe broke the world record in the 400m freestyle at the 2000 Sydney Olympics, winning the gold medal in a time of 3:40.59.
Most country no.1s for a female artist in the us
Andy Morez
57.2 secs is the Pacific School Games record for 13 year old girls 400m record. It was set in 1984 by Vanessa Fielding. Records can be found in the related link.
Stephanie Rice