Athletics at the 2008 Summer Olympics – Men's 400 metres  The men's 400 metres at the 2008 Summer Olympics took place on 18–21 August at the Beijing National Stadium. The defending champion was Jeremy Wariner, who also won World Championship titles in 2005 and 2007 preceding the 2008 Olympics. Wariner made headlines earlier in the season when he dropped long time coach Clyde Hart, in favor of Hart's assistant Michael Ford. All season, Wariner did not show the dominance of the previous three seasons. At the Olympic Trials he was runner up to LaShawn Merritt, the World Championship silver medalist. The semi-finals showed the same two in the same position, Merritt .03 faster than Wariner. Wariner started fast in the final: running in lane 7, he caught up with Martyn Rooney to his outside making up the stagger before the 200 mark. Further outside but more difficult to calculate, David Neville was also out fast, while Merritt was even relative to the stagger against Chris Brown in lanes 4 and 5. Around the final turn Merritt separated from the others and the three Americans were ahead, with Neville in first as the turn was ending. Once they hit the straightaway, it was Merritt who had the speed, sprinting away with a high knee action that increased his gap over Wariner and Neville. Wariner had no answer, Neville looked depleted, while Brown was steadily gaining. Merritt sped away to a personal best 43.75, Wariner gave up the chase and jogged across the finish line in second, barely ahead of Brown, who looked like he had passed Neville. In the last two steps, Neville leant forward and fell right at the finish line, his hands technically crossing the line ahead of Wariner. But it is the torso that counts and Neville's body crossed the line in third, .04 ahead of Brown and .06 behind Wariner. Merritt had gained just shy of a full second on Wariner over the last 90 metres for the win. Neville completed an American sweep of the event. Prior to this competition, the existing world and Olympic records were as follows:  No new world or Olympic records were set for this event. Each National Olympic Committee (NOC) was able to enter up to three entrants providing they had met the A qualifying standard (45.55) in the qualifying period (1 January 2007 to 23 July 2008). NOCs were also permitted to enter one athlete providing he had met the B standard (45.95) in the same qualifying period.