"Sprinting Off The Top"

Is this term used more to define the process of how the swing leg is loaded up as it passes the opposite knee in sprinting? Or the function of CM horizontal/vertical velocity generated from the propulsive effects during the getaway phase?

I assuming both have to do with some positive vertical displacement during toe-off and flight phase. However, is this term meant as a pro-active movement skill or step during certain sprint drills or work sessions? And if so, how might it be performed?