Rule of the thumb

By T.J. TOMASI

A common piece of advice to cure a slice is to increase the rotation of the forearms. Since forearm rotation closes the face, that is good advice, but there is a right way and a wrong way to do this.

The correct release mechanics are what I call the Sidewinder Release: The forearms rotate but do not initiate the release — that is the ­function of the wrists. As the lead wrist uncocks, the lead forearm ­begins to roll via momentum, and it is this combination — wrist ­release/forearm roll — that brings the ­clubface square.

The vectors of force both toward the ground and to the target produce the famous Hogan arch of the lead wrist, a slight bow that all good players have. Note that the arch is a result of what went before, not a cause in itself.

In order to make this unfolding sequence work, the grip must be fit to the task. Use too weak a grip and the face stays open, causing a slice; too strong a grip shuts down the face, leading to a hook.

And here we encounter another common piece of advice that is true but incomplete: Adjust the strength of the grip by using the knuckles as a guide. It is said that if you want to weaken the grip, you should rotate the hands counterclockwise until you can see only one knuckle on your lead hand. To summon the draw, look for three; if you can see two knuckles, it’s neutral.

This is nice and neat, but misleading. It’s not the knuckles that confer face rotation; it’s the lead thumb. If you arrange your grip so the shaft is between the thumb and the target, its leveraged position will shut the face. Place the thumb on top of the shaft and it will tend to leave the face open.

The purpose of the grip is to guarantee control of the club without inducing tension. When the hands are arranged correctly, no manipulations are necessary to return the clubface correctly at impact. A good golf grip activates the muscles you want to use in the golf swing, while an incorrect grip does just the opposite — it encourages use of the wrong muscles.