Diamond League: Ones to watch in Rome

Reigning three-time Olympic and world champion and world record holder Usain Bolt will hope to strike his familiar victory pose following the men's 100m in Rome on Thursday

1903 BST: Men's 400m hurdles

Welshman Dai Greene was imperious in 2010 and the European and Commonwealth gold medallist will have to be at his gladiatorial best in Rome. He faces a formidable challenge led by the respective Olympic and world champions, Angelo Taylor and Kerron Clement.

The form athlete, though, is South African LJ van Zyl, who pushed Greene hard at the Commonwealth Games and has since set the top three times in the world this year. European and Commonwealth medallist, Rhys Williams, is the other Briton in the field.

1930 BST: Women's 400m

Allyson Felix and Sanya Richards-Ross, the 200m and 400m world champions respectively, compete over both distances in Rome.

First up is the 400m, in which Felix set the world-leading time of 50.33 seconds at the first Diamond League meeting of the season, in Doha. She has only defeated Richards-Ross once in five meetings over the distance - back in 2007 - but is unbeaten in their four races over 200m in that period.

The two Americans cannot afford to concentrate solely on each other in Rome, as the line-up also includes Olympic and world silver medallist Shericka Williams and Commonwealth champion, Amantle Montsho, who ran Felix close in Doha.

1940 BST: Men's triple jump

Great Britain's world and European champion, Phillips Idowu, begins his outdoor season and will be looking to remind younger rival Teddy Tamgho of his ability. Frenchman Tamgho, who broke his own indoor world record at the European Indoor Championships in March, is not in Rome but the rest of the world's top five are in action.

In addition, Olympic gold medallist, Nelson Evora, returns to international competition for the first time since August 2009. The Portuguese missed much of 2010 after undergoing an operation on a stress fracture in his right leg.

1950 BST: Women's 100m hurdles

Lolo Jones has been below her best this season

The five fastest sprint hurdlers of the year are American and they are all part of a superb line-up in Rome.

World indoor champion Lolo Jones is the highest-ranked hurdler on show but the 28-year-old has so far been below her best this season and was only third at the Diamond League meeting in Doha, as well as in her last outing in Daegu, South Korea.

Kellie Wells set a world-leading time of 12.58 in Doha but finally lost her unbeaten record in 2011 when runner-up to Dawn Harper in Daegu. Canada's former world champion Perdita Felicien competes outdoors for the first time this season, while USA-born Briton Tiffany Ofili is also in action.

2000 BST: Women's 1500m

Lisa Dobriskey was hampered by injury last year but the World Championship silver medallist has not shied away from a challenge by entering this race.

Seven of the world's top 10 are in Rome, including top-ranked Nancy Jebet Langat, who last year added the Commonwealth and African titles to her Olympic gold medal. Double world champion, Maryam Yusuf Jamal, and 800m Olympic and world silver medallist, Janeth Jepkosgei, are other names to watch.

2045 BST: Men's 100m

The world's highest-profile athlete returns to action after an uncharacteristically low-key year. Usain Bolt was not in the best shape in 2010 after injuring his ankle, and cut short his season due to a back problem after suffering only his second ever 100m defeat - by Tyson Gay in Stockholm.

Bolt's competition in Rome includes former world record holder Asafa Powell, who won at the previous Diamond League meeting in Shanghai, Trinidad's Olympic silver medallist, Richard Thompson, and European champion, Christophe Lemaitre, who clocked 10.08 seconds in his native France on Sunday despite suffering cramp during the race.