User:Jbakum/sandbox

Long course

 * Murray Rose's 4:25.9 set in a 25-metre pool on 12 Jan 1957 was only valid until 1 May the same year. Due to the new rule that records must be set in a 50-metre pool, and the fact that neither John Marshall's 4:26.9 from 1951, nor Ford Konno's 4:26.7 from 1954 were set in 50-metre pools, the WR reverted to Rose's 4:27.0 from 1956.