The 400 metres, or 400-meter dash, is a sprint event in track and field competitions. It has been featured in the athletics programme at the Summer Olympics since 1896 for men and since 1964 for women. On a standard outdoor running track, it is one lap around the track. Runners start in staggered positions and race in separate lanes for the entire course. In many countries, athletes previously competed in the 440-yard dash (402.336 m)—which is a quarter of a mile and was referred to as the "quarter-mile"—instead of the 400 m (437.445 yards), though this distance is now obsolete.
Shaunae Miller-Uibo is a Bahamian track and field sprinter who competes in the 200 and 400 metres. She is a two-time Olympic champion after winning the women's 400 metres at the 2016 Rio Olympics and again at the 2020 Tokyo Olympics.
The women's 400 metres event at the 2016 Summer Olympics took place between 13–15 August at the Olympic Stadium.
Salwa Eid Naser is a Nigerian-born Bahraini sprinter who specialises in the 400 metres. She was the 2019 World champion with the third fastest time in history of 48.14 seconds, becoming the youngest-ever champion in the event and also the first woman representing an Asian nation to win that event at a World Championships. The mark places her only behind contested results of Marita Koch and Jarmila Kratochvílová. Over the distance, at only 19, Naser was the 2017 World silver medallist. She has also won, as a member of the Bahraini mixed-gender 4x400 m relay team, the 2019 World Championships bronze medal.
The women's 200 metres at the 2017 World Championships in Athletics was held at the London Olympic Stadium on 8 and 10−11 August.
The women's 400 metres at the 2017 World Championships in Athletics was held at the London Olympic Stadium on 6−7 and 9 August.
The women's 4 × 400 metres relay at the 2017 World Championships in Athletics was held at the London Olympic Stadium on 12–13 August.
The women's 200 metres event at the 2020 Summer Olympics took place on 2 and 3 August 2021 at the Japan National Stadium. 41 athletes from 31 nations competed. In successfully defending her title, Elaine Thompson-Herah became the first woman in history to win both the 100 and 200 metres titles at successive games. Her winning time of 21.53 secs, moved her to second on the world all-time list behind Florence Griffith Joyner, and broke Merlene Ottey's 30-year-old Jamaican record. The winning margin was 0.28 seconds. Surprisingly, Thompson-Herah had the slowest reaction time in the final.
The women's 400 metres event at the 2020 Summer Olympics took place from 3 to 6 August 2021 at the Japan National Stadium. 45 athletes from 34 nations competed. Shaunae Miller-Uibo won the gold medal by 0.84 seconds in a personal best of 48.36 secs, a time which ranks her sixth on the world all-time list. In successfully defending her title, Miller-Uibo joined Marie-Jose Perec as the only women to win two Olympic 400 metres titles.
The men's 400 metres hurdles at the 2019 World Athletics Championships was held at the Khalifa International Stadium in Doha from 27 to 30 September 2019.
The mixed 4 × 400 metres relay at the 2019 World Athletics Championships was held at the Khalifa International Stadium in Doha from 28 to 29 September 2019.
The women's 200 metres at the 2019 World Athletics Championships was held at the Khalifa International Stadium in Doha, Qatar, from 30 September to 2 October 2019.
The women's 400 metres hurdles at the 2019 World Athletics Championships was held at the Khalifa International Stadium in Doha, Qatar, from 1 to 4 October 2019.
The women's 4 × 400 metres relay at the 2019 World Athletics Championships was held at the Khalifa International Stadium in Doha, Qatar, from 5 to 6 October 2019. In the final the Jamaican team were initially disqualified, but were reinstated as the bronze medallists upon appeal.
The women's 400 metres at the 2022 World Athletics Indoor Championships took place on 18 and 19 March 2022.
The women's 200 metres at the 2022 World Athletics Championships was held at the Hayward Field in Eugene, Oregon, U.S. from 18 to 21 July 2022.
The women's 400 metres at the 2022 World Athletics Championships was held at the Hayward Field in Eugene, Oregon, U.S. from 17 to 22 July 2022.
The women's 400 metres hurdles at the 2022 World Athletics Championships was held at the Hayward Field in Eugene, Oregon, United States, from 19 to 22 July 2022. It was won by Sydney McLaughlin in a world record time of 50.68 seconds. The winning margin was 1.59 seconds which as of 2024 stands as the greatest winning margin for the women's 400 metres hurdles at these championships.
The women's 400 metres at the 2023 World Athletics Championships was held at the National Athletics Centre in Budapest, Hungary from 20 to 23 August 2023. The winning margin was 0.81 seconds which as of 2024 is the only time the women's 400 metres has been won by more than 0.7 seconds at these championships.
The women's 400 metres at the 2024 Summer Olympics was held in four rounds at the Stade de France in Paris, France, between 5 and 9 August 2024. This was the sixteenth time that the women's 400 metres was contested at the Summer Olympics. A total of 48 athletes were able to qualify for the event by entry standard or ranking.
