Justin Gatlin

After serving a four-year ban for a positive doping test, the 2004 gold medalist in the 100 meters is back at the Olympics in search of redemption. It's been a long, strange trip for Gatlin, who reached the pinnacle of the sprinting world only to fall from grace due to a 2006 test that showed excessive testosterone. He tried out for multiple NFL teams during his time away from the track, but returned in 2010 and quickly returned to form. This year, he won gold in the 60 meters at the world indoor championships before taking first place at the U.S. trials with a personal-best time of 9.80 seconds. "Usually, I have a lot of words. I'm almost speechless," the 30-year-old Gatlin said. "Everything just feels so surreal. I just let the heart really go out and do what it had to do." When asked how much faster he can go in London, Gatlin said, "enough to win another gold," but he'll face a daunting challenge from Usain Bolt and his Jamaican teammates. Bolt hadn't yet emerged when Gatlin won gold in Athens, where the American added a bronze medal in the 200 meters and a silver in the 4x100 relay. Gatlin won double gold at the 2005 world championships in the 100 and the 200, receiving the Jesse Owens Award as the top American track and field performer for the second straight year, but he's avoiding the longer sprint in London to focus on the premier running event of the Games.