Jon Henricks set the 100-metre freestyle world record of 55.4 seconds at the 1956 Melbourne Olympics.
Notes on verification
Confirmed by multiple independent authoritative sources including Olympedia, ISHOF, Sport Australia Hall of Fame, and Wikipedia's world record progression table, with technical nuance about time-trial vs official records corroborated.
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://www.stateofswimming.com/happy-80th-birthday-lance-larson-sub-minute-butterfly-pioneer-who-triggered-the-timepad/ (stateofswimming.com)