Jim Stone talks about how to engage the core during the setting motion. The setter's aim is to always be square to the passers in order to know the trajectory of the pass, and then attempt to square the shoulders in the direction of the hitter while setting the ball. Often, this will require dynamically rotating the torso and shoulders to face the hitter. This movement requires a strong core, and setters should always maintain a braced core during rotational movements to prevent injury.
