Full Highlights of the first round of heats in the men's 4x400m relay event at the London 2012 Olympic Games.

During the second heat, the USA's first runner Manteo Mitchell broke his leg at the 200m mark of the race and still managed to finish the race, helping USA claim second place in an amazing display of Olympic spirit.

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Since 1896, athletics has been on the programme of each edition of the Games of the Olympiad. Its presenc