The Olympic 400m men freestyle record is 3:40.59 by Ian Thrope.
43.18 by Michael Johnson
2:54.20 by USA in 1998
Michael Johnson: 43.18 seconds.
43.18 seconds set by Michael Johnson in 1999 is still the current world record
The world record, as well as the Olympic record, for the mens' 200 meter freestyle was set by Michael Phelps on August 12th, 2008, at the Beijing Summer Olympics. His time was 1:42.96 .
The world record for the 1500 meter freestyle is.... 14:34.56 by Grant Hacket (Australia) July 29, 2001 The world record for the women is.... 15:42.54 by Kate Ziegler (USA) June 17, 2007
The mens short course world reored is held by Paul Bierdermann-- 3:32.77
Paul Biedermann 1:42.00 in Rome, Italy on July 28, 2009.
The question is a little unclear as to whether it is the 100m swimming or running world record. The world record for the age group 50 - 54 years mens 100m freestyle is 54.61 seconds held by Paul Trevison