Your Shoulders are the Flywheel
We discussed in Step Four how your shoulders should rotate around the spine. They are the last of the center-rotating parts of your body, and can be considered the “flywheel” of the golf swing. In an engine, the flywheel is a heavy disk of steel that stores momentum and provides heft. In your golf swing, the shoulders transmit the power created by the legs and body into the arms, which, relatively speaking, swing freely. If you have ever seen a robot golf club tester, you have probably seen how its arms are connected loosely to a flywheel. The robot can hit shot after shot in exactly the same way - its flywheel always spins at the angle at which it has been set.