where tAIR represents the total airborne time, and frTO and frTD represent
the numbers of the takeoff and touchdown frames, respectively,
estimated to the nearest half-frame. Takeoff was defined as
the last frame in which the second takeoff foot to leave the ground
was in contact with the ground before the block. Touchdown was
defined as the first frame in which the first foot to touch the ground
again after the block made contact with the ground.