|Men's 400 metres|
at the Games of the XXX Olympiad
|Competitors||52from 38 nations|
The first round went largely to form, but defending champion Lashawn Merritt came to the meet injured and re-injured himself, unable to finish. Renny Quow also failed to start his heat. In the first race, Oscar Pistorius ran a season best to qualify. In the second heat, world champion Kirani James ran easily to win. The third heat featured three national records as Jonathan Borlée took his twin brother's mark for Belgium (Kevin also qualified in the seventh heat), Pavel Maslák set the mark for the Czech Republic and Donald Sanford set the mark for Israel. Most of the time qualifiers came from the hotly contested fourth heat, 45.61, the slowest time qualifier, though Conrad Williams got in with a 46.12 in the slow sixth heat.
It took under 45 seconds to make the final as Lalonde Gordon led the qualifiers from heat 1. Heat 2 featured James and Jonathan Borlée, and double-amputee Pistorius' attempt to make the final. But Pistorius' late charge was non-existent and he finished last in the heat. After the race, in a show of sportsmanship, James and Pistorius exchanged bib numbers, which James proudly showed as he celebrated. In the third heat, shotgun survivor Bryshon Nellum ran 45.02 for the fastest non-qualifier.
Aside from Chris Brown, the finals were filled by athletes under age 24, three of them still teenagers. Demetrius Pinder took the early lead down the back stretch, but reigning World Junior Champion Luguelin Santos (age 18) and reigning World Champion Kirani James (age 19) were in the lead coming off the turn. Down the stretch, James powered ahead for the gold medal.. It was also the first Olympic medal for his country. Lalonde Gordon came from behind but could not overtake Santos; he received a bronze. Santos' silver medal was the third medal for the Dominican Republic, coming 45 minutes after Felix Sánchez won his second gold.
The Men's 400m competition consisted of 7 heats (Round 1), 3 semifinals and a final. The fastest competitors from each race in the heats qualified for the Semifinals along with the fastest overall competitors not already qualified that were required to fill the 24 available spaces in the semifinals. A total of eight competitors qualified for the final from the semifinals.
Prior to the competition, the existing World and Olympic records were as follows.
|World record||Michael Johnson (USA)||43.18||Seville, Spain||26 August 1999|
|Olympic record||43.49||Atlanta, United States||29 July 1996|
|2012 World leading||LaShawn Merritt (USA)||44.12||Eugene, OR, United States||24 June 2012|
|Broken records during the 2012 Summer Olympics|
|2012 World leading||Kirani James (GRN)||43.94||London, United Kingdom||6 August 2012|
The following new National records were set during the competition.
|Belgium National Record||Jonathan Borlée (BEL)||44.43 s|
|Czech Republic National Record||Pavel Maslák (CZE)||44.91 s|
|Israel National Record||Donald Sanford (ISR)||45.71 s|
|Grenada National Record||Kirani James (GRN)||43.94 s|
|Saturday, 4 August 2012||10:35||Round 1|
|Sunday, 5 August 2012||20:40||Semifinals|
|Monday, 6 August 2012||21:30||Finals|
Qual. rule: first 3 of each heat (Q) plus the 3 fastest times (q) qualified.
|1||Luguelín Santos||Dominican Republic||0.187||45.04||Q|
|2||Oscar Pistorius||South Africa||0.236||45.44||SB||Q|
|N/A||Ahmed Mohamed Al-Merjabi[a]||Oman||N/A||N/A||DNS|
|N/A||Renny Quow||Trinidad and Tobago||N/A||N/A||DNS|
[a] Ahmed Mohamed Al-Merjabi was forced to scratch from this race after he injured his foot in a training session three days earlier.
|3||Liemarvin Bonevacia||Independent Olympic Athletes||0.232||45.60||PB||Q|
|5||Deon Lendore||Trinidad and Tobago||0.205||45.81|
|8||Bahaa Al Farra||Palestine||0.212||49.93||SB|
|2||Pavel Maslák||Czech Republic||0.186||44.91||NR||Q|
|6||Nelson Stone||Papua New Guinea||0.193||46.71||SB|
|8||Ak Hafiy Tajuddin Rositi||Brunei||0.188||48.67||PB|
|2||Bryshon Nellum||United States||0.191||45.29||Q|
|3||Yousef Ahmed Masrahi||Saudi Arabia||0.147||45.43||PB||Q|
|4||Tabarie Henry||Virgin Islands||0.176||45.43||q|
|8||Zaw Win Thet||Myanmar||0.181||50.07|
|2||Tony McQuay||United States||0.155||45.48||Q|
|3||Nigel Levine||Great Britain||0.148||45.58||Q|
|2||Lalonde Gordon||Trinidad and Tobago||0.178||45.43||Q|
|3||Conrad Williams||Great Britain||0.164||46.12||Q|
|N/A||LaShawn Merritt||United States||0.195||N/A||DNF|
|2||Martyn Rooney||Great Britain||0.186||45.36||Q|
|4||Nery Brenes||Costa Rica||0.237||45.65|
Qual. rule: first 2 of each heat (Q) plus the 2 fastest times (q) qualified.
|1||7||Lalonde Gordon||Trinidad and Tobago||0.168||44.58||PB||Q|
|5||4||Pavel Maslák||Czech Republic||0.166||45.15|
|6||2||Tabarie Henry||Virgin Islands||0.167||45.19||SB|
|8||3||Conrad Williams||Great Britain||0.153||45.53|
|4||9||Tony McQuay||United States||0.230||45.31|
|6||3||Nigel Levine||Great Britain||0.146||45.64|
|8||5||Oscar Pistorius||South Africa||0.254||46.54|
|1||5||Luguelín Santos||Dominican Republic||0.155||44.78||Q|
|3||6||Bryshon Nellum||United States||0.173||45.02|
|5||7||Martyn Rooney||Great Britain||0.186||45.31|
|7||9||Yousef Ahmed Masrahi||Saudi Arabia||0.146||45.91|
|8||3||Liemarvin Bonevacia||Independent Olympic Athletes||0.153||96.42||[note 1]|
|5||Kirani James||Grenada||0.163||43.94||WL, NR|
|7||Luguelín Santos||Dominican Republic||0.185||44.46|
|4||Lalonde Gordon||Trinidad and Tobago||0.159||44.52||PB|