2. Yohan Blake (Jamaica, Sprinter, 100 and 200 meters)
Usain Bolt’s training partner, the youngest sprinter to break the 10-second barrier in the 100-meter dash (at 19), is also his biggest threat. Blake won the 100-meter gold medal in the 2011 World Championships, after Bolt was disqualified with a false start—does he now have the confidence to overtake him on his own?