What is Lag in Golf?

Lag is what makes a 110 mph clubhead speed possible from a 90 mph arm swing. At the top of the backswing the wrists are fully hinged and the angle between the lead arm and the shaft is around 90 degrees. As the lower body starts the downswing, that angle is held — that's the lag — until the very last moment when the wrists release and the clubhead whips through impact at maximum speed. The longer the angle is held, the more energy gets dumped into the ball.

The opposite of holding lag is casting. Casting is throwing the clubhead away from the body too early in the downswing, releasing the wrists before they should. The result is a swing that looks fine on the way back but is already out of speed when it reaches the ball. Most amateur golfers cast because they are trying to use their hands and arms to hit at the ball instead of letting the body rotation and the wrist release do the work in sequence.

You cannot manufacture lag by squeezing the grip or trying to hold the angle consciously. Lag is a byproduct of correct sequence — when the lower body leads and the arms follow, the wrists naturally retain their angle until the body slows and forces the release.