The Accelerating Thrust of Centrifugal Force is a Pulling Lengthwise Motion which results in a Throw Out Action. It can be accomplished by the Left Arm or the Right Arm, both are in a condition to Pull. It is your choice which one you use. Left Arm Swingers (using the Left Shoulder as the Stroke Center) use the Pivot to create a Transfer of Body Momentum. Right Arm Swingers (using the Right Elbow as the Stroke Center) use the Right Tricep to Pull and may not need thet use of Body Momentum.