Ryan Steven Lochte is an American former competition swimmer and 12-time Olympic medalist. He is the third-most decorated swimmer in Olympic history measured by total number of medals, behind only Michael Phelps and Katie Ledecky. Lochte's seven individual Olympic medals rank second in history in men's swimming, tied for second among all Olympic swimmers. He currently holds the world records in the 200-meter individual medley. As part of the American teams, he also holds the world record in the 4×200-meter freestyle and 4×100-meter freestyle (mixed) relay.
Mireia Belmonte García is a Spanish Olympic, world, and European champion swimmer. She is the world record holder in the short course 200 metre butterfly and 400 metre individual medley. Formerly, she held the world record in the short course 400 metre freestyle, 800 metre freestyle, and 1500 metre freestyle. She was the first Spanish woman to win a gold medal in swimming at an Olympic Games and is widely considered to be the greatest Spanish swimmer of all time.
This article includes the world record progression for the 4×100 metres medley relay, and it shows the chronological history of world record times in that competitive swimming event. The 4×100 metres medley relay is a medley race in which each of four swimmers on a team swims a 100-metre leg of the relay, each swimming a different stroke, in the following sequence:
- Backstroke
- Breaststroke
- Butterfly
- Freestyle.
Martin Liivamägi is an Estonian swimmer, who specialized in breaststroke and individual medley events. He is a two-time Olympian, a 2010 Pac-10 champion in the 200 m individual medley, a double NCAA team titleholder, a 43-time Estonian swimming champion, and a 24-time national record holder in different age groups. He also won a silver medal in the same stroke at the 2006 European Junior Swimming Championships in Palma de Mallorca, Spain.
Michael Fred Phelps II is an American former competitive swimmer. He is the most successful and most decorated Olympian of all time with a total of 28 medals. Phelps also holds the all-time records for Olympic gold medals (23), Olympic gold medals in individual events (13), and Olympic medals in individual events (16). At the 2004 Summer Olympics in Athens, Phelps tied the record of eight medals of any color at a single Games, held by gymnast Alexander Dityatin, by winning six gold and two bronze medals. Four years later, when he won eight gold medals at the 2008 Beijing Games, he broke fellow American swimmer Mark Spitz's 1972 record of seven first-place finishes at any single Olympic Games. At the 2012 Summer Olympics in London, Phelps won four gold and two silver medals, and at the 2016 Summer Olympics in Rio de Janeiro, he won five gold medals and one silver. This made him the most successful athlete of the Games for the fourth Olympics in a row.
Giedrius Titenis is a Lithuanian swimmer, who specialized in breaststroke events. He is a four-time Olympian, a multiple-time Lithuanian record holder in the men's breaststroke, and a double swimming champion in the same discipline at the 2011 Summer Universiade in Shenzhen, China. Titenis is also a member of Anykščiai Swimming Club, and is coached and trained by Žilvinas Ovsiukas.
Jördis Steinegger is an Austrian swimmer who specialized in freestyle and individual medley events. She is a two-time Olympian, a nine-time long and short course Austrian record holder, and a member of the Linz Amateur Swimming Club in Linz, under her personal coach Marco Wolf.
Kosuke Hagino is a Japanese former competitive swimmer who specialized in the individual medley and 200 m freestyle. He is a four-time Olympic medalist, most notably winning gold in the 400 m individual medley at the 2016 Summer Olympics.
Raphaël Stacchiotti is a Luxembourgish swimmer, who specialized in the freestyle and individual medley events. He is a four-time Olympian, a multiple-time Luxembourgian record holder in all freestyle and medley events, and a double European junior champion. Stacchiotti also holds numerous meet records and collects a total of 49 medals from the Games of the Small States of Europe. At the 2008 Summer Olympics, Stacchiotti became the youngest athlete to be chosen by the Luxembourg squad, and was given the honor of carrying the nation's flag in the opening ceremony.
Jung Won-Yong is a South Korean swimmer, who specialized in freestyle and individual medley events. He won a bronze medal, as a member of the South Korean swimming team, in the 400 m freestyle relay at the 2010 Asian Games in Guangzhou, China.
Glenn Surgeloose is a Belgian swimmer, who specializes in sprint freestyle events. He collected a bronze medal in the 200 m freestyle at the 2007 European Junior Swimming Championships in Antwerp, Belgium. Surgeloose is a member of Brabo Antwerp, and is coached and trained by Ronald Gaastra.
Irakli Bolkvadze is a Georgian swimmer, who specialized in breaststroke and individual medley events. He won a bronze medal in the boys' 200 m breaststroke at the 2012 European Junior Swimming Championships in Antwerp, Belgium with a time of 2:15.46. Bolkvadze is also trained by his personal coach Irina Minjulina.
Pieter Timmers is a Belgian retired competitive swimmer who specialized in sprint freestyle events. He won the silver medal in the 100 meter freestyle at the 2016 Olympics. Timmers currently holds nine Belgian records, and seven national titles in long and short course freestyle. Timmers is a resident athlete for Brabo Antwerp, and trains under his personal coach Ronald Gaastra. He stands 2.00 m, and weighs 89 kg (196 lb). He ended his career in Budapest in the second season of the International Swimming League in 2020.
Yoris Grandjean is a Belgian swimmer, who specialized in sprint freestyle events. He won two gold medals at the 2006 FINA Youth World Swimming Championships, and later represented Belgium at the 2008 Summer Olympics. Since 2009, he still currently holds a Belgian record (22.13) in the 50 m freestyle from the national championships in Antwerp. Grandjean also trains for Liège Swimming Club under his head coach Andre Henvaux.
Daiya Seto is a Japanese professional swimmer who specializes in individual medley, butterfly, breaststroke, and freestyle events. He holds the world record in the short course 400-metre individual medley and formerly held the world record in the short course 200-metre butterfly. He won the gold medal in the 400-metre individual medley at the 2012, 2014, 2016, 2018, 2021, and 2022 world short course championships, as well as at the 2013, 2015, and 2019 world long course championships.
Yves Platel is a Swiss former swimmer, who specialized in freestyle and individual medley events. He is a two-time Olympian, and currently holds four Swiss records in long-distance freestyle and the 400 m individual medley. Platel is a member of Genève Natation 1885 in Geneva, and is coached and trained by Dirk Reinecke.
Chase Tyler Kalisz is an American swimmer who specializes in individual medley events. He is an Olympic gold medalist in the 400-meter individual medley at the 2020 Summer Olympics in Tokyo, an Olympic silver medalist at the 2016 Summer Olympics in Rio de Janeiro and a two-time World Aquatics Championships gold medalist.
Travis Mahoney is an Australian medley and backstroke swimmer. Winner of two relay medals at the 2012 World Short Course Championships, he is also part of the quartet that broke the world record in the short course mixed 4 × 50 metres freestyle relay. In 2016, he qualified for his first Olympic Games.
Roos Vanotterdijk is a Belgian competitive swimmer. She is the Belgian record holder in the long course 50 metre freestyle, 100 metre freestyle, 50 metre backstroke, 100 metre backstroke, and 100 metre butterfly, as well as the short course 50 metre backstroke and 100 metre individual medley. She is a six-time medalist in individual events at the European Junior Swimming Championships and medalist at the European Youth Olympic Festival.
Belgium 
