How Fast Can a Human Run?
How much of your stride is on the ground?
"...one (primary) mechanical limit for bipedal runners, from all the work that we’ve done, it’s the minimum period of foot ground contact,” he said. “A human who’s really fast, like Usain Bolt, is on the ground roughly 42 or 43 percent of the total stride time. But for a fast-running quadruped” — a cheetah, a horse — “it’s two-thirds of the stride time.”