Jon Henricks set the 100-metre freestyle Olympic record of 55.4 seconds at the 1956 Melbourne Olympic Games.
Notes on verification
Multiple independent, high-quality sources (Olympics.com, Olympedia, Wikipedia, ISHOF, Sport Australia Hall of Fame) confirm the time, event, and record status. Minor nuance about pre-existing time-trial record does not contradict the claim.
Sources
- The science games — ABC Science Archive (abc.net.au)
- https://www.olympics.com/en/athletes/jon-malcolm-henricks (olympics.com)
- https://www.olympedia.org/athletes/45218 (olympedia.org)
- https://sahof.org.au/hall-of-fame-member/jon-henricks/ (sahof.org.au)
- https://ishof.org/honoree/honoree-jon-henricks/ (ishof.org)
- https://sahof.org.au/hall-of-fame-member/john-devitt/ (sahof.org.au)
- https://github.com/irenedelatorre/swimming-records/blob/master/data/20170306-swimming-times3.csv (github.com)