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 $100m$ 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 $9.52s$ 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 $2s$ 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 $0.5m∕s2$ greater than the runner-up. We find that the new world record in these two cases would have been $9.61±0.04$ and $9.55±0.04s$⁠, respectively, where the uncertainties denote 95% statistical errors.