The wrist set is a vital component of the golf swing. It is one of two fulcrums that are used to generate power in the swing itself; the second being the elbow furthest away from the target at address. The proper use of the wrist set governs the structure of the rear arm in the back swing, the plane, the club face, and the proper synchronization of the arms to the body. In short, the wrist set is the heart beat of the golf swing.
Assuming one's grip is correct, this action consists of a bending back and up of a rear hand and the flattening of the forward hand (note: the degree of up and back for both hands in this motion varies according to the placement of the club in the swing). This motion sets the club on plane and orients the rearward elbow to a position where the club can continue on plane to the top of the back swing. This condition is preferred because it helps synchronize the arm swing to the body turn. Many times if the wrist set does not occur properly, the rear elbow will be out of position causing a host of problems.
In my mind, the wrist set is the great secret of the golf swing. Its function allows many things. The wrists set the club on plane. The wrist cock provides proper structure of the rear arm. The proper structure of the rear arm allows the arms to be synchronized to the body. It is one of two fulcrums that orient the body - to support the club on plane - in a powerful, loaded position.
Mark Grace Golf