Set By: Usain Bolt
Was Bolt actually trying when he ran a 9.63 100m dash at the Olympics this past summer? We'll never really know, but it sure seemed like he might have been able to shave a little time off of that. Even if he did, though, he very well may have still been short of his own world record he set in 2009. The Jamaican is just 26 years old, so he probably has another year or two to try to topple his own incredible feat.