Believe it or not

Fast and slow runners move their legs at about the same rate. What separates the two classes of runners is that the fast runners exert much more force on the ground.
source: Wikipedia article on ‘Footspeed’.
Furthermore, this means that there is a match-up between the phenomenon of footspeed and the phenomenon of rocketry. For a given burn, the change in speed of a rocket (in free space, using the rocket equation of Konstantin Tsiolkovsky) depends on the amount of mass ejected, and the rate of its ejection. The leg speed of a runner corresponds to the amount of mass ejected from the rocket, and the force exerted by the runner on the ground corresponds to the rate of ejection of mass from the rocket.
Here’s the Wikipedia article on Tsiolkovsky’s rocket equation.