Novlene Hilaire Williams-Mills, is a retired Jamaican track and field athlete. She won the bronze medal in the 400 metres at the 2007 World Championships. She is also a three-time Olympic silver medallist in the 4×400 metres relay. In 2015 she won relay gold alongside her Jamaican teammates.
Marc Burns is an athlete from Trinidad and Tobago specializing in the 100 metres and the 4 x 100 metres relay.
Shericka Williams is a Jamaican former sprinter. Together with Novlene Williams, Ronetta Smith and Lorraine Fenton she won a silver medal in 4 × 400 metres relay at the 2005 World Championships in Athletics. She also competed in the individual contest, but was knocked out in the semifinal. Two years later, she won another silver medal in the 4 × 400 metres relay event at the 2007 World Championships in Athletics, this time with Shereefa Lloyd, Davita Prendergast and Novlene Williams. The team set a national record in that race, finishing second to the United States in a time of 3:19.73.
Christine Ijeoma Ohuruogu, MBE is a British former track and field athlete who specialised in the 400 metres, the event for which she is an Olympic, World and Commonwealth champion. The Olympic champion in 2008, and silver medalist in 2012, she is a double World Champion, having won the 400 m at the 2007 and 2013 World Championships. She has also won six World championship medals in the women's 4 × 400 m relay as part of the Great Britain and Northern Ireland team and bronze Olympic medals with the women's 4 × 400 m relay at the 2008 Beijing Games and the 2016 Rio Games, her final Olympics. Ohuruogu shares with Merlene Ottey and Usain Bolt the record for medalling in most successive global championships – 9 – between the 2005 World Championships in Athletics and the 2016 Summer Olympics.
Shereefa Lloyd is a Jamaican sprinter, who specializes in the 400 metres.
Since the early 20th century, Jamaica has won 42 Commonwealth Golds, 14 World Championship Golds and 17 Olympic gold medals in athletics alone. Jamaica has a population of 2.85 million people, making it the 138th most populous country in the world.
Bronte Amelia Arnold Barratt, OAM is a retired Australian competitive swimmer and Olympic gold medallist.
Lauren Marie Boyle is a former competitive swimmer from New Zealand. She has competed at three Commonwealth Games and three Olympic Games.
The women's 400 metres at the 2009 World Championships in Athletics was held at the Olympic Stadium on 15, 16 and 18 August. The world-leader prior to the competition, Sanya Richards, was regarded as the favourite in the event, although her previous failure to convert circuit dominance to major championship success raised some doubts. Reigning Olympic and world champion Christine Ohuruogu entered the championships as only the 25th fastest in the world that year, although a low-key run up also preceded her previous victories. Jamaicans Shericka Williams and Novlene Williams-Mills were predicted as possible medallists, while Russian Antonina Krivoshapka held the second fastest time in the world prior to the tournament.
Spencer gave birth to son Michael Carter Jr on April 25,2021
The Women's 400 metres at the 2011 World Championships in Athletics was held at the Daegu Stadium on August 27, 28 and 29.
Emily Diamond is a British track and field athlete, who competes in the 200 metres and 400 metres. Diamond came to prominence in her breakout season of 2016 when, following her first win at the British Championships over the 400 metres distance, she collected a gold medal in the 4 x 400 metres relay at the 2016 European Athletics Championships as part of the Great Britain team, followed by a bronze in the same discipline at the 2016 Summer Olympics.
Schillonie Calvert is a Jamaican sprinter who specializes in the 100 metres. She made the 4x100 relay team for Jamaica as a reserve for the 2011 World Championships in Athletics in Daegu and the 2012 Summer Olympics in London. She did not participate at the 2012 Worlds. She ran in the 4 × 100 m heat with the Jamaican team at the 2012 London Olympics which later went on to take silver in the finals. She competed as an individual in the 100 m at the 2013 World Championships, where she was also part of the Jamaican team that won gold in the 4 × 100 m. She competed in the 100 m, 200 m and 4 × 100 m at the 2014 Commonwealth Games, and was part of the 4 × 100 m team that set a new Games record.
Regina George Grause is an American-born Nigerian sprinter who specializes in the 400 metres. She represented Nigeria at the 2012 Summer Olympics and was the silver medallist at the African Championships in 2012.
Christine Sonali Merrill, also simply known as Christine Merill, is a former Sri Lankan–American track and field athlete and mechanical engineer. During her career, she specialized in the 400m hurdles event and also occasionally competed in 100m, 200m, 100m hurdles, 4 × 100m relay and 4 × 400m relay events.
Stephenie Ann McPherson is a Jamaican track and field athlete, who specializes in the 400 metres. She has won a bronze medal in the event at the 2013 World Championships, and then placed in the finals of both the 2016 Rio Olympics and the 2020 Tokyo Olympics and all four following World Championships between 2015 and 2022, consecutively. McPherson earned also a bronze at the 2022 World Indoor Championships. She added medals in the 4 x 400 metres relays, taking a silver at the 2016 Olympics, a gold in 2015 in Beijing, and a bronze in 2019.
The women's 4 × 400 metres relay competition at the 2016 Summer Olympics in Rio de Janeiro, Brazil was held at the Estádio Olímpico João Havelange on 19–20 August.
The women's 4 × 400 metres relay at the 2015 World Championships in Athletics was held at the Beijing National Stadium on 29 and 30 August.
Anneliese Rubie is an Australian sprinter. Also known as Anneliese Rubie-Renshaw, she was a semi finalist at the 2016 Rio Olympics, and the 2015 World Championships in Beijing. She also ran in the semi-finals at the 2014 Commonwealth Games in Glasgow. She ran the second leg for the women's 4 × 400 m which made the Olympic final in 2016.
Patience Okon George is a Nigerian sprinter. She competed in the 400 metres event at the 2015 World Championships in Athletics in Beijing, China and also at the 2016 Rio Olympic Games. George is a two-time African Championships bronze medallist in the individual 400 metres event. She is also a three-time Nigerian national champion in the 400 metres.
Jamaica 
