Is that what they taught you to do when you are arriving as the ball is? What if the ball is in the air? They call it a kill shot for a reason, the receivers head is turned to the QB as he crosses over the middle, the defenders eyes light up because he's seen the play thousands of times in film. You know exactly where the receiver is going to be and you turn and sprint toward him. The throw is a little high and you aim for the mid section, he leaps and you hit waist as his hands touch the ball. In highschool you can get away with the technique you described but in the nfl when the receivers hands touch the ball he's supposed to catch it. You hit a NFL receiver in the waist as he catches the ball 9/10 its a completed catch. You hit him in the upper body/head with a shoulder as his head whips around, the ball comes loose.