Hurdlers in action (© AFP/Getty Images)
The mixed shuttle hurdles relay, one of two new disciplines making their debut at the IAAF World Relays Yokohama 2019, will figure prominently on the event's first day, as it opens the weekend's action with the heats and concludes day one with the final.
So, what is it?
As the name suggests, it features two men and two women on each team, running 110m legs. The race will begin with the women running their standard 100m hurdles race from the finish line towards the traditional start, but running an extra 10 metres at the end of their leg to account for the extra distance.
They will then change over to the first man on the team who will run the standard 110m back up the straight in the adjacent lane and then change over to the second woman, who in turn will change over the second man who will run the anchor leg.
Seven countries have entered teams, with the USA arriving armed with a line-up strong enough to consider them the favourites. Their six-member pool includes 2016 Olympic finalist Devon Allen and 13.27 runner Freddie Crittenden on the men's side, and 2018 world indoor silver medallist Christina Clemons, national indoor champion Sharika Nelvis and 2015 Pan-American Games champion Queen Harrison on the women's.
Ronald Levy leads a strong Jamaican squad that looks ready to battle the US squad to the line. Levy raced to the Commonwealth title last year and finished runner-up at the Continental Cup, so brings solid big meet credentials to Yokohama International Stadium. Two-time Olympian Andrew Riley and Yanique Thompson, the 100m hurdles Commonwealth bronze medallist in 2018, are also in the line-up.
France, meanwhile, is led by reigning European 110m hurdles champion Pascal Martinot-Lagarde, the most decorated athlete in the field. The 27-year-old has collected nine world and European medals since 2012, including two silver medals in the 60m hurdles at World Indoor Championships. He'll be joined by Wilhem Belocian, the world U20 champion, national indoor 60m hurdles champion Sacha Alessandrini and Laura Valette, the Youth Olympic Games champion in 2014.
China should be in the medal picture as well, led by Chen Jiamin and Wu Yanni, who were second and fifth in the 100m hurdles at last month's Asian Championships, and Zeng Jianhang, who was seventh in the men's 110m hurdles in that same competition.
Japan should also contend. Ayoko Kimura and Masumi Aoki, the gold and bronze medallists at the Asian Championships, head the women's half of the line-up, and Shunya Takayama and Taio Kanai, fourth and fifth at the Asian Championships, the men's.
Bob Ramsak for the IAAF