Maoulida Darouèche is a Comoran hurdler who specialises in the 400 metres hurdles and who has also competed in the javelin throw. Darouèche competed in the 2012 Summer Olympics and the 2016 Summer Olympics. At both Olympics he competed in the 400 metres hurdles. He has also competed in two World Championships, an African athletics championships and a Jeux de la Francophonie.
Justine Bayigga is a Ugandan sprinter, who specialized in the 400 metres. Bayigga represented Uganda at the 2008 Summer Olympics in Beijing, where she competed in the women's 400 metres. She ran in the second heat, against six other athletes, including Italy's Libania Grenot, and future world-record holder Amantle Montsho of Botswana. She completed the sprint race in last place, with a time of 54.15 seconds, failing to advance into the semi-finals.
Mowen Boino is a Papua New Guinean track and field athlete, who specialized in 400 metres and in 400 metres hurdles. He is a three-time Olympian and four-time national record holder for the 400 m hurdles. He also achieved his personal best time of 50.37 seconds at the 2006 Commonwealth Games in Melbourne, Australia.
Carline Muir is a Canadian sprinter, who specialized in the 400 metres. She won the bronze medal for the 400 metres, and ultimately, led her national team to claim the sprint relay title at the 2009 Summer Universiade in Belgrade, Serbia. She is also a three-time junior national champion, a two-time silver medalist at the Canadian Track and Field Championships.
Ivano Bucci is a Sammarinese sprinter, who specialized in the 400 metres. Bucci qualified for the 2008 Summer Olympics in Beijing, by shattering both his personal best and a national record of 48.07 seconds at the 2007 IAAF World Championships in Osaka, Japan.
Dimitrios Gravalos is a Greek sprinter, who specialized in the 400 metres. He won the gold medal for the 400 metres at the 2003 European Junior Championships in Tampere, Finland, with a time of 46.54 seconds.
Sayaka Aoki is a Japanese track and field sprinter and hurdler, who specializes in the 400 metres sprint and 400 metres hurdles. She competed for her country as part of the Japanese women's 4 × 400 metres relay team at the Summer Olympics in 2008 and the World Championships in Athletics three times. She has been a four-time medallist in the relay at the Asian Athletics Championships, including a gold medal in 2011. She won her first major international medal in the hurdles – a bronze – at the 2017 Asian Athletics Championships.
Myhaylo Mykolayovych Knysh is a Ukrainian sprinter, who specialized in the 400 metres. Knysh made his official debut for the 2004 Summer Olympics in Athens, where he placed sixth for the national sprint team in the preliminary heats of men's 4 × 400 m relay, with a time of 3:04.01.
Félix Adolfo Martínez Cuevas is a Puerto Rican sprinter, who specialized in the 400 metres. He set both a national record and a personal best time of 45.92 seconds by finishing third for the 400 metres at the 2007 Ponce Grand Prix in Ponce.
Pieter Smith is a South African sprinter, who specialized in the 400 metres. He set his personal best time of 45.63 seconds by winning the 400 metres event at the 2009 South African Championships in Stellenbosch.
Pedro Juan Mejía Eusebio is a Dominican sprinter, who specialized in the 400 metres. He won two bronze medals, as a member of the Dominican Republic national team, in the men's 4 × 400 m relay at the 2007 Pan American Games in Rio de Janeiro, Brazil, and at the 2008 IAAF World Indoor Championships in Valencia, Spain.
Joel Japheth Phillip is a retired Grenadian sprinter, who specialized in the 400 metres. He set a personal best time of 45.29 seconds, by finishing ninth at the 2008 Pac-10 Conference Championships in Tempe, Arizona.
Geiner Alonso Mosquera Becerra is a Colombian sprinter, who specialized in the 400 metres. He won a gold medal at the 2008 Ibero-American Championships, with a time of 46.63 seconds.
Cowin Mills is a Trinidadian sprinter, who specialized in the 400 metres. He is a 2007 NCAA All-American honoree, and a member of the track and field team for the Clemson Tigers. He is also a graduate of management at Clemson University in Clemson, South Carolina.
Stann Waithe is a Trinidadian sprinter, who specialized in the 400 metres. He is a member of the track and field team for the Michigan Wolverines, while attending the University of Michigan in Ann Arbor, Michigan.
Rudolf Götz is a Czech sprinter, who specialized in the 400 metres. He set a personal best time of 45.78 seconds at the 2008 Ostrava Golden Spike in Ostrava, earning him a spot on the Czech track and field team for the Olympics. He is also a member of the athletics team for ASK Slavia Praha, and is coached and trained by Petr Novotny.
Onalenna Oabona Baloyi is a Botswana middle distance runner, who specialized in the 800 metres.
Ashley Spencer is an American track and field athlete who competes in the 400 metres and the 400 metres hurdles. In the 400m hurdles, she is the 2016 Olympic bronze medalist. In the 400m, she is the 2012 World Junior Champion and the 2016 World Indoor silver medalist. She is coached by 1996 Olympic bronze medalist Tonya Buford-Bailey.
Wayde van Niekerk is a South African track and field sprinter who competes in the 200 and 400 metres. In the 400 metres, he is the current world and Olympic record holder, having set the record when he won the event at the 2016 Olympics.
Ned Justeen Azemia is a Seychellois hurdler who specialises in the 400 metres hurdles. He is the current Seychellois record holder in the event. Azemia competed in the 2016 Summer Olympics in Rio de Janeiro in the 400 metres hurdles. He has also competed in two World Junior Championships, an African athletics championships and an African Youth Games. Azemia has also raced over the flat 400 metres distance.
Botswana 
