How fast could Usain Bolt have run? A dynamical study

Since that memorable day at the Beijing 2008 Olympics, a big question has been, 'What would the 100 m dash world record have been had Usain Bolt not celebrated at the end of his race?' Bolt's coach suggested that the time could have been 9.52 s or better. We consider this question by measuring Bolt's position as a function of time using footage of the run, and then extrapolate the last 2 s with two different assumptions. First, we conservatively assume that Bolt could have maintained the runner-up's acceleration during the end of the race. Second, based on the race development prior to the celebration, we assume that Bolt could have kept an acceleration of 0.5 m/[s.sup.2] greater than the runner-up. We find that the new world record in these two cases would have been 9.61 [+ or -] 0.04 and 9.55 [+ or -] 0.04 s, respectively, where the uncertainties denote 95% statistical errors.