Elaine Thompson-Herah, Shelly-Ann Fraser-Pryce, Briana Williams and Shericka Jackson celebrate their 4x100m win in Tokyo (© Getty Images)
As the year draws to a close, we look back at the key moments of 2021 in each area of the sport.
The series begins with a review of the relays and will be followed over the coming days by reviews of all the other event groups.
Women’s 4x100m
Season top list
| 41.02 | Jamaica 🇯🇲 JAM | Tokyo | 6 August |
| 41.45 | United States 🇺🇸 USA | Tokyo | 6 August |
| 41.55 | Great Britain & NI 🇬🇧 GBR | Tokyo | 5 August |
| 42.00 | Germany 🇩🇪 GER | Tokyo | 5 August |
| 42.05 | Switzerland 🇨🇭 SUI | Tokyo | 5 August |
Olympic medallists
| 🥇 | Jamaica 🇯🇲 JAM | 41.02 NR |
| 🥈 | United States 🇺🇸 USA | 41.45 |
| 🥉 | Great Britain 🇬🇧 GBR | 41.88 |
| Full results | ||
Season trends
As they did in 2019, Jamaica top the event thanks to their Olympic gold medal-winning national record time of 41.02 in Tokyo. There Briana Williams, Elaine Thompson-Herah, Shelly-Ann Fraser-Pryce and Shericka Jackson combined to run the third-fastest ever time to regain a title last won by the nation in Athens in 2004.
In 2019, three national teams – Jamaica, Germany and Great Britain & NI – dipped under 42 seconds, a feat replicated this year by Jamaica, United States and Great Britain, although Germany came very close with the team clocking exactly 42 seconds in the Tokyo heats.
The same four teams led the way during the last Olympic year, with United States’ 41.01 topping the list in 2016. There was similar depth, too, with 21 teams going sub-43 seconds in 2021 compared to 22 in 2016 and 20 in 2019.
History was made at U20 level, with the Jamaican quartet of Serena Cole, Tina Clayton, Kerrica Hill and Tia Clayton running 42.94 to break the world U20 record and win gold at the World Athletics U20 Championships in Nairobi. The U20 teams of the top three countries this season – Jamaica, Namibia and Nigeria – each dipped under 44 seconds.
Men's 4x100m
Season top list
| 37.50 | Italy 🇮🇹 ITA | Tokyo | 6 August |
| 37.51 | Great Britain & NI 🇬🇧 GBR | Tokyo | 6 August |
| 37.70 | Canada 🇨🇦 CAN | Tokyo | 6 August |
| 37.79 | PR of China 🇨🇳 CHN | Tokyo | 6 August |
| 37.82 | Jamaica 🇯🇲 JAM | Tokyo | 5 August |
Olympic medallists
| 🥇 | Italy 🇮🇹 ITA | 37.50 NR |
| 🥈 | Great Britain & NI 🇬🇧 GBR | 37.51 SB |
| 🥉 | Canada 🇨🇦 CAN | 37.70 SB |
| Full results | ||
Season trends
Never before had an Italian quartet broken 38 seconds but in Tokyo the team achieved it twice, with Lorenza Patta, Marcell Jacobs, Eseosa Desalu and Filippo Tortu coming together in the final to clock a world-leading national record of 37.50 to continue the nation's gold rush at the Games.
They won by just 0.01, with Great Britain's 37.51 the fastest ever Olympic silver medal-winning time. Behind Canada's 37.70, the 37.79 by fourth-placed China and 37.84 by fifth-placed Jamaica are the two fastest times to not win a medal at the Olympic Games.
The year 2019 was the greatest ever for the event and nine nations went sub-38 seconds, compared to five in 2021. During the last Olympic year in 2016, the figure was eight.
Following the success of the nation's senior team that gained 4x100m gold at the World Athletics Relays in Poland in May, South Africa's Mihlali Xhotyeni, Sinesipho Dambile, Letlhogonolo Moleyane and Benjamin Richardson broke the world U20 record with their 38.51 at the World Athletics U20 Championships in Nairobi. They were one of three nations – along with Jamaica and Poland – whose U20 teams dipped under 39 seconds during the year.
Women's 4x400m
Season top list
| 3:16.85 | United States 🇺🇸 USA | Tokyo | 7 August |
| 3:20.53 | Poland 🇵🇱 POL | Tokyo | 7 August |
| 3:21.24 | Jamaica 🇯🇲 JAM | Tokyo | 7 August |
| 3:21.84 | Canada 🇨🇦 CAN | Tokyo | 7 August |
| 3:22.59 | Great Britain & NI 🇬🇧 GBR | Tokyo | 7 August |
Olympic medallists
| 🥇 | United States 🇺🇸 USA | 3:16.85 |
| 🥈 | Poland 🇵🇱 POL | 3:20.53 NR |
| 🥉 | Jamaica 🇯🇲 JAM | 3:21.24 |
| Full results | ||
Season trends
In Tokyo, Sydney McLaughlin, Allyson Felix, Dalilah Muhammad and Athing Mu combined to clock 3:16.85 – the fastest time in 28 years. That saw them win by almost four seconds to extend the USA’s winning streak at the Olympic Games that dates back to 1996.
That margin was the amount that the USA led the season top list by, too, with Olympic silver medallists Poland second on 3:20.53. The gap between the two was three seconds in 2019 – a year in which four countries went sub-3:24.00. In 2021, a total of seven nations dipped under that mark.
The winning team at the World Athletics Relays was Cuba, and the nation went on to finish eighth in the Olympic final – a great improvement on the sixth place in their heat the team achieved at the World Athletics Championships in Doha.
The world U20 top list featured similar dominance to the senior list, with Nigeria leading the way thanks to the team's 3:31.46 set when winning at the World U20 Championships. Germany came closest with their 3:35.38 in Tallinn.
Men's 4x400m
Season top list
| 2:55.70 | United States 🇺🇸 USA | Tokyo | 7 August |
| 2:57.18 | Netherlands 🇳🇱 NED | Tokyo | 7 August |
| 2:57.27 | Botswana 🇧🇼 BOT | Tokyo | 7 August |
| 2:57.88 | Belgium 🇧🇪 BEL | Tokyo | 7 August |
| 2:58.46 | Poland 🇵🇱 POL | Tokyo | 7 August |
Olympic medallists
| 🥇 | United States 🇺🇸 USA | 2:55.70 WL |
| 🥈 | Netherlands 🇳🇱 NED | 2:57.18 NR |
| 🥉 | Botswana 🇧🇼 BOT | 2:57.27 AR |
| Full results | ||
Season trends
The USA also claimed gold in the men's Olympic 4x400m final, with Michael Cherry, Michael Norman, Bryce Deadmon and Rai Benjamin running 2:55.70 – the fourth-fastest time in history.
With four teams dipping under 2:58, seven teams going sub-2:59 and all eight teams inside 3:01, it was the deepest men’s 4x400m race in history.
The top five times in that final – run by the USA, Netherlands, Botswana, Belgium and Poland – also topped the season list, with the Netherlands having won the event at the World Athletics Relays in Poland. In a year of great depth, eight nations went sub-2:59 throughout 2021, compared to three in 2019 and four in the last Olympic year of 2016.
Botswana led the U20 list thanks to the 3:05.22 run by Busang Collen Kebinatshipi, Anthony Pesela, Oreeditse Masede and Phenyo Bongani Majama to win at the World Athletics U20 Championships in Nairobi.
Mixed 4x400m
Season top list
| 3:09.87 | Poland 🇵🇱 POL | Tokyo | 31 July |
| 3:10.21 | Dominican Republic 🇩🇴 DOM | Tokyo | 31 July |
| 3:10.22 | United States 🇺🇸 USA | Tokyo | 31 July |
| 3:10.36 | Netherlands 🇳🇱 NED | Tokyo | 31 July |
| 3:11.51 | Belgium 🇧🇪 BEL | Tokyo | 31 July |
Olympic medallists
| 🥇 | Poland 🇵🇱 POL | 3:09.87 OR |
| 🥈 | Dominican Republic 🇩🇴 DOM | 3:10.21 NR |
| 🥉 | United States 🇺🇸 USA | 3:10.22 SB |
| Full results | ||
Season trends
Poland made history in Tokyo, becoming the first Olympic champions in the mixed 4x400m. With the event being held at the Games for the first time, the team of Karol Zalewski, Natalia Kaczmarek, Justyna Swiety-Ersetic and Kajetan Duszynski combined to run a world-leading 3:09.87 to get gold ahead of the Dominican Republic and the United States.
The world all-time list was unsurprisingly rewritten, with the USA remaining top thanks to their 3:09.34 run at the 2019 World Athletics Championships in Doha but eight of the top 10 performances all having been run in Tokyo.
Four teams went sub-3:11 and seven dipped under 3:12, compared to one and three respectively in 2019.
Italy had won the title at the World Athletics Relays, with Edoardo Scotti, Giancarla Trevisan, Alice Mangione and Davide Re running 3:16.60 for victory in Silesia.
Like Poland, Nigeria also made history on the global stage by winning the inaugural world U20 mixed 4x400m title in Nairobi. There Johnson Nnamani, Imaobong Nse Uko, Opeyemi Oke and Bamidele Ajayi combined to clock a world U20-leading 3:19.70. There was more medal success for Poland, as they also dipped under 3:20 to secure silver, while India claimed bronze in 3:20.60.
World Athletics
