5. Tyson Gay, USA, Sprinter: Gay holds the American record in the 100-meter race with a time of 9.69 seconds, second-best all-time to Bolt's 9.58 seconds. Along with Justin Gatlin, Yohan Blake, and Asafa Powell, Gay will be one of the sprinters to watch in the 100-meter final on Aug. 5. as the runners battle it out to be called the world's fastest man.