Francena McCorory of the USA crosses the finish line ahead of Shericka Williams of Jamaica to secure victory in the women's 4x400 metres relay (Getty Images) © Copyright
These teams have occupied the three podium places at the past three Olympics, and at three of the past five World Championships.
The trend looks set to continue, and it should be another close race. While it was Jamaica who pushed the USA at last year’s World Championships, this year Russia looks to have the stronger team with the four fastest members of their squad having run 50.00 or quicker for 400m this season. They include world leader Antonina Krivoshapka, Olympic finalist Yuliya Gushchina, 2010 European Champion Tatyana Firova, and two-time World Indoor Champion Natalya Nazarova.
But relays don’t always go to the form book and the USA – boosted by the presence of former World champion Sanya Richards-Ross – will want to hold on to their title. She is the only member of their team to have gone sub-50 this year, but the likes of DeeDee Trotter and Francena McCorory are strong relay runners.
As the only sub-50 Jamaican runner this year, Novlene Williams-Mills will be the key member of her national team, but they might not be as strong as they were last year when they set a national record of 3:18.71 to take silver in Daegu. While Christine Day has been in PB form, Shericka Williams and Rosemarie Whyte have been some way off their best.
Great Britain is the only other nation to have got within the medals at the past five World Championships, taking bronze in 2005 and 2007. As the reigning World Indoor Champions – combined with the expected boost in support from the home crowd – they must be respected. Their strengths will rest with Olympic 400m champion Christine Ohuruogu and European 400m hurdles bronze medallist Perri Shakes-Drayton, who is capable of a sub-50 split at her best.
Beyond the big medal contenders, Ukraine will field a strong team. They finished fourth at last year’s World Championships and more recently won the European title in Helsinki.
The Czech Republic is also more than capable of making it to the final. Bolstered by hurdles specialists Zuzana Hejnova and Denisa Rosolova, they took bronze at this year’s European Championships.
Belarus finished fourth at the last Olympics, and although they won’t be expected to finish as high this time around, they are still likely finalists. The same holds true for European silver medallists France and World and Olympic finalists Nigeria.
Jon Mulkeen for the IAAF