Both 400 IM world records were bettered at the 2008 Olympics yesterday, when first USA’s Michael Phelps swam 4:03.84, smashing his own world record of 4:05.25 from the U.S. Olympic Trials, and Australia’s Stephanie Rice swam 4:29.45, more than half a second faster than the 4:31.12 of Katie Hoff from the U.S. Trials.
Sources: SwimInfo here and here
