Bronze medalist Justin Gatlin of the United States and gold medalist Usain Bolt of Jamaica celebrate after competing in the Men?s 100m Final on Day 9 of the London 2012 Olympic Games at the Olympic Stadium on August 5, 2012 in London, England. (Photo by Michael Steele/Getty Images)
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Olympics Day 9 - Athletics
Usain Bolt of Jamaica celebrates after crossing the finish line to win the gold medal in the Men's 100m Final on Day 9 of the London 2012 Olympic Games at the Olympic Stadium on August 5, 2012 in London, England. (Photo by Shaun Botterill/Getty Images)
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Olympics Day 9 - Athletics
Usain Bolt of Jamaica celebrates winning gold in the Men?s 100m Final on Day 9 of the London 2012 Olympic Games at the Olympic Stadium on August 5, 2012 in London, England. (Photo by Stu Forster/Getty Images)
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Olympics Day 9 - Athletics
Usain Bolt of Jamaica crosses the finish line ahead of Ryan Bailey of the United States, Yohan Blake of Jamaica and Justin Gatlin of the United States to win the Men's 100m Final on Day 9 of the London 2012 Olympic Games at the Olympic Stadium on August 5, 2012 in London, England. (Photo by Michael Steele/Getty Images)
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Olympics Day 9 - Athletics
Usain Bolt of Jamaica celebrates winning gold in the Men?s 100m Final on Day 9 of the London 2012 Olympic Games at the Olympic Stadium on August 5, 2012 in London, England. (Photo by Stu Forster/Getty Images)
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Olympics Day 8 - Athletics
LONDON, ENGLAND - AUGUST 04: (L-R) Usain Bolt of Jamaica and James Dasaolu of Great Britain compete in the Men's 100m Round 1 Heats on Day 8 of the London 2012 Olympic Games at Olympic Stadium on August 4, 2012 in London, England. (Photo by Stu Forster/Getty Images)
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Usain Bolt repeats as victor of the talent-packed men's 100-meter race, retaining the title of 'world's fastest man.' Here's a look at him and his challengers. -- By Lauren Jones, Yahoo! Sports