VRP:I don't want to let the receiver get behind me.		Green: I want to keep the receiver in front of me.
There is more liklihood that a pass receiver will get behind a defending back if the defender tells himself what he does NOT want to do rather than what action he DOES wish to accomplish. The defender's brain can take an extra moment to decode the "not", giving the receiver an opportunity to exploit the moment and gain a valuable step.		Saying the specific action that IS wanted saves mental decoding time and allows the defender quicker responses to fast changing conditions on the field.