Medley swimming in the context of World record progression 400 metres individual medley

Ian James Thorpe AM (born 13 October 1982) is an Australian retired swimmer who specialised in freestyle, but also competed in backstroke and the individual medley. He has won five Olympic gold medals, the second most won by any Australian after fellow swimmer Emma McKeon. With three gold and two silver medals, Thorpe was the most successful athlete at the 2000 Summer Olympics, held in his hometown of Sydney.

At the age of 14, Thorpe became the youngest male ever to represent Australia, and his victory in the 400 metre freestyle at the 1998 Perth World Championships made him the youngest-ever individual male World Champion. After that victory, Thorpe dominated the 400 m freestyle, winning the event at every Olympic, World, Commonwealth and Pan Pacific Swimming Championships until his break after the 2004 Olympics in Athens. At the 2001 World Aquatics Championships, he became the first person to win six gold medals in one World Championship. Aside from 13 individual long-course world records, Thorpe anchored the Australian relay teams, numbering the victories in the 4 × 100 m and the 4 × 200 m freestyle relays in Sydney among his five relay world records. His wins in the 200 m and 400 m and his bronze in the 100 m freestyle at the 2004 Summer Olympics made him the only male to have won medals in the 100–200–400 combination. He acquired the nickname "Thorpedo" because of his speed in swimming. Thorpe announced his retirement from competitive swimming in November 2006, citing waning motivation; he made a brief comeback in 2011 and 2012.

The International Olympic Committee recognises the fastest performances in pool-based swimming events at the Olympic Games. Men's swimming has been part of the official program of the Summer Olympics since the Games' modern inception in 1896; it was not until 1912 that women's events were held. The swimming events at the 1896 Olympic Games were held in a bay in the Aegean Sea with swimmers being required to swim to the shore—Hungarian swimmer Alfréd Hajós won two gold medals that year, saying "My will to live completely overcame my desire to win." The 1900 Summer Olympic Games in Paris had the swimming events take place in the River Seine, and the events at the 1908 Summer Olympics were held in a 100-metre pool surrounded by an athletics track in the White City Stadium in London.

Races are held in four swimming categories: freestyle, backstroke, breaststroke and butterfly, over varying distances and in either individual or relay race events. Medley swimming races are also held, both individually and in relays, in which all four swimming categories are used. In the Swimming at the 2024 Summer Olympics in Paris, both men and women competed in eighteen events in the pool. Of the 35 pool-based events, swimmers from the United States hold fifteen records, Australia five, France four, China, Canada and South Africa two each, and one each to Ireland, Great Britain, Russian Olympic Committee, Hungary, and Sweden. Nineteen of the current Olympic records were set at the 2024 Summer Olympics, seven in 2020, five in 2016, one in 2012, and three in 2008.