Pendulum Swing

This is a full extension arm action that externally rotates the humerus, engages the muscles of the flexor-pronator mass, and turns the forearm over early.

When executed properly, this can prevent late forearm turnover and reverse forearm bounce.

This type of ball pick-up is detailed by Dr. Marshall in Chapter 37 of his free online book (see Online Reading). He summarized it very briefly in an email to me:

To get their pitching arm in the maximum acceleration position, I teach my baseball pitchers to pendulum swing their pitching arm downward, backward and upward in straight lines toward second base to driveline height with the palm of their pitching hand facing away from their body in one smooth, continuous movement pointing at second base.