The pressure through the center of the bow makes arrow spine less critical, works the limbs right, and removes torque.
Try this to feel push pull, I am stealing from GFA a little. Pull back and hold, have someone watch. Usually you end up slumping a little and collapsing, and get a soft, bad release.
Now, draw again, but before you release squeeze a little more pull and push as you stare at the spot and Bang, the arrow flies great and the follow through is easier.
Howards form was amazing, that arrow left and nothing moved a lot of time. Rock solid. Again, he was shooting bows that probably felt like toys to him. Pick up a kids bow and see how you do, probably darn well for arrow release and form!