Swingers should think Momentum Transfer (of the Body via the Pivot into the inert Left Arm).
Pivot in the inert left arm? Does that mean turn you body and chest into the left bicep on the down swing until force drives the arm off the chest?
Yes...the Primary Lever Assembly (Left Arm and Club) is accelerated by the Momentum Transfer of the turning Body (through the #4 Pressure Point -- where the Left Arm contacts the side of the chest). Specifically, it is accelerated by the unwinding of the coiled left side via the Right Shoulder Turn thrust.