Interactive Graphic: Lolo Jones, Cleared for Takeoff Sources: Motion-capture data from Red Bull; Richard Kirby, sport technologist; Ralph V. Mann, Ph.D., author of "The Mechanics of Sprinting and Hurdling" Clearing the hurdle Click and drag! Form and Function Efficiency equals speed when clearing the hurdle: hit a precise takeoff point; create the right arc on the jump and land without braking.