I was curious if anybody knows how the zone-read handoff actually works. From what I see, the quarterback puts the ball in the running back's chest every time.
How does the running back know whether or not to take it?
That's an excellent article. The short answer is the running back doesn't take until the QB leaves it in his belly (and in best practice, firmly presses it in to leave no doubt in the RBs mind that he's to take it). It's the QBs decision to give (his first option) or keep (only if the read is there).