LaShawn Merritt in the 400m at the 2012 Samsung Diamond League in Doha (Jiro Mochizuki) © Copyright

Men's 400 Metres - PREVIEW

On paper, U.S. champion LaShawn Merritt appears to be a strong favourite to defend his 400m title, with the last major pre-London race – Monaco’s Herculis Samsung Diamond League fixture – illustrating more precisely where his primary challengers may lie.

That race was won by Belgian Jonathan Borlée, who clocked a near-PB 44.74 to edge World champion Kirani James by just 0.02 seconds. Jonathan's twin brother, Daegu bronze medallist, Kevin, who's improved to 44.56 this season, was third ahead of this season’s breakout star, freshly-minted World junior champion Luguelin Santos of the Dominican Republic.

Meanwhile, Merritt pulled up as a precaution with about 100 metres to go when hit by a hamstring cramp. All raced on tired legs in the midst of their last heavy pre-Olympic training sessions, suggesting that each has another three or four tenths of a second - at the very least - in reserve. Which still, on paper, leaves the majority of the field well behind the American’s best this season.

Outside of his Monaco DNF, Merritt has been unbeaten in six races this year with his 44.12 SB from the U.S. trials leading the world - he's also clocked 44.19, the season's second fastest time - by more than three-tenths of a second.

The closest is the 18-year-old Santos, whose 44.45 victory in Hengelo was a national record. Two weeks later he made the world take further note after he collected his first victory on the Diamond League circuit in New York.

Busy with his studies, James, still just 19, has raced sparingly this season, winning in Daegu (44.72 SB) and London (44.85) prior to the race in Monaco. In the Principality, he confirmed that his training's been going according to plan but it’s nonetheless important to bear in mind that he was notably faster last year in his final pre-Daegu outing.

Backing up Merritt on a traditionally strong U.S. squad – Americans have won the last seven Olympic titles and swept the podium in Beijing and Athens - are Tony McQuay and Bryshon Nellum, whose relative inexperience shouldn’t count against them in an event where plenty of youngsters have excelled and outlived expectations in the past.

McQuay, 22, won the NCAA title in 44.58 16 days before improving to 44.49 at the U.S. trials where he finished second. More recently he was third in London clocking 45-flat.

Nellum meanwhile has already secured plenty of votes as a comeback athlete of the year. Entering 2012 with a 45.56 personal best, the 23-year-old university student improved all the way to 44.80 at the U.S. trials to finish third - 44 months after gunshot wounds to both legs left him wondering if he’d ever run again.

Fourth (Kevin) and sixth (Jonathan) at 44.56 and 44.74 on this year's world list respectively, medal-winning runs by the Borlée twins are not outside the realm of possibility - but would be unprecedented. To date siblings have never medalled in the same event at an Olympic Games.

Other medal hopefuls include Bahamian No. 1 Demetrius Pinder (44.77) and Jamaican champion Dane Hyatt (44.83) while Martyn Rooney (44.92) will be the main hope for the hosts.

Finally, one thing that’s not conspiring in Merritt’s favour is history: only World record holder Michael Johnson (1996, 2000) has been able to win back-to-back 400m titles.

Bob Ramsak for the IAAF