Kerron Stephon Clement is a Trinidadian-born American track and field athlete who competes in the 400-meter hurdles and 400-meter sprint. He held the indoor world record in the 400-meter sprint, having broken Michael Johnson's mark in 2005.
The 4 × 400 metres relay or long relay is an athletics track event in which teams consist of four runners who each complete 400 metres or one lap. It is traditionally the final event of a track meet. At top class events, the first leg and the first bend of the second leg are run in lanes. Start lines are thus staggered over a greater distance than in an individual 400 metres race; the runners then typically move to the inside of the track. The slightly longer 4 × 440 yards relay, on an Imperial distance, was a formerly run British Commonwealth and American event, until metrication was completed in the 1970s.
Andrew Rock is an American sprinter who specializes in the 400 meter dash.
Marek Plawgo is a Polish athlete. He mainly competes in the 400 meters hurdles, but he also starts in the 400 meters and the 4 x 400 meters relay.
Michael Mathieu is a retired Bahamian sprinter from Freeport, Grand Bahama who specialized in the 200 metres and 400 metres. He was part of the Bahamian silver medal-winning team in the men's 4×400 metres relay at the 2008 Beijing Olympics, running second leg and recording a 44.0 split, and the gold medal-winning team at the 2012 Summer Olympics. He was also a part of second place relay team at the 2007 World Championships. He won the bronze medal in the 4x400 metres relay in the 2016 Summer Olympics.
Brenda Taylor is an American track and field athlete who specialises in the 400 meter hurdles. She reached the final of the event at the 2004 Summer Olympics. She also competed at the 2001 World Championships in Athletics and won a medal at the 2003 IAAF World Indoor Championships in the 4×400-meter relay.
Brandon Johnson is an American former professional middle-distance runner, who specialized in the 800 metres and previously the 400 meter hurdles until 2012.
Ayomide Temilade Oluwatoyosi Folorunso is an Italian athlete specialising in the 400 metres hurdles. She competed in the 4 × 400 metres relay at the 2015 World Championships in Beijing.
Michael Arthur Norman Jr. is an American sprinter. He holds the world best time in the indoor 400 meters at 44.52 seconds. Outdoors, his 43.45, set at the 2019 Mt. SAC Relays is tied as the #4 on the all time list. In 2016, he became the world junior champion in both the 200 meters and 4×100 meter relay. In 2022, he became the world champion in both the 400 meters and 4x400 meter relay.
Raevyn Rogers is an American middle-distance athlete. She won a bronze medal in the 800 meters at the 2020 Tokyo Olympics, becoming the fourth fastest woman in U.S. history in the event. At the 2019 World Championships, Rogers came from seventh with 100m remaining in the race to place silver over USA teammate Ajeé Wilson in bronze. She earned a world indoor title as a member of national 4x400 m relay squad that took gold at the 2018 World Indoor Championships.
Courtney Okolo is an American track and field sprinter who usually competes in the 400 metres. She starred at Carrollton (Texas) Newman Smith High School where she won multiple individual state championships.
Byron Robinson is an American track and field athlete who competes in the 400 metres hurdles. He holds a personal record of 48.58 seconds for the event. He was the runner-up at the United States Olympic Trials in 2016.
Kendall Ellis is an American sprinter. Ellis won gold in the 4x400 m relay and bronze in the Mixed 4x400 metres at the Tokyo Olympics. She competed in the 400 meters at the 2017 and 2019 World Championships, winning gold medals as a part of prelim 4×400 m relays. As a junior, Ellis took gold in the 4×400 m relay and bronze in the 400 meters at the 2015 Pan American Junior Championships.
Dominique Blake is a Jamaican track and field athlete. Blake won a gold medal at the 2010 Central American and Caribbean Games and was accidentally awarded a bronze medal at the 2012 Summer Olympics. She was banned for 4+1⁄2 years after testing positive for methylhexanamine and returned to athletic competition in 2017.
Abderrahman Almoubarrake Samba Alsaleck is a Qatari male track and field athlete who specialises in the 400 metres hurdles. He was born and grew up in Saudi Arabia but chose to represent Mauritania – his father's homeland – before eventually switching allegiance to Qatar and moving to Doha in 2015. He became eligible to compete for his adopted country in May 2016. He was the second person to run the 400m hurdle event in less than 47 seconds.
Rai Benjamin is an American professional hurdler and sprinter specializing in the 400 m and 400 m hurdles. He is the second fastest man in history in the 400 m hurdles with a personal best time of 46.17 s. Benjamin won silver medals at his first Olympic Games in 2021 and at the World Championships in 2019 and 2022 in the men's 400 m hurdles, and gold medals in the 4 × 400 m relay in 2019 and 2021.
Stanley Grant Holloway is an American professional hurdler and sprinter. He is a three-time world champion, 2020 Tokyo Olympic silver medalist in the 110 meters hurdles and the second-fastest man in history at the event with a personal best of 12.81 seconds, set at the U.S. Olympic Trials on June 26, 2021. In the 60 meters hurdles, Holloway is the 2022 World Indoor champion and the world indoor record holder with a time of 7.29 seconds set in Madrid, Spain on February 24, 2021.
Ilolo Izu is an American sprinter, specialized in the 400 metres hurdles and 400 metres.
Charokee Young is a track and field athlete from Jamaica.
Italy 
