In the modern, total body golf swing, where the rotating torso is the major power generator of the golf swing, the arms and hands are flung around, and in front, of the rotating body during the downswing. The major function of the hands is to hold firmly onto the golf club - the hands should be thought of as simply being "clamps" that firmly hold onto the Taylormade Rocketballz RBZ Irons while the club is swung through the impact zone. The hands should not actively manipulate the golf club during the impact zone. It is stated on http://www.golfnewonline.com/Mizuno-MP-59-Irons-USA_287.html "that one should think of the hands as conductors through which the speed and power created by the turning motion of your body is transferred to the clubhead".
Wrist action accounts for 90 percent of bad shots. Why is this so common? The natural way to control the Miznuo JPX 800 Irons is with the hands and any attempt to use the hands encourages breaking of the wrists. There are two directions the wrists can move in the golf swing. That is the forward/backward or up and down. I am going to refer to the forward/backward action as the breaking of the wrists. The up/down as the hinging of the wrists. Some teachers call the up/down movements cocking the wrists.
In order for this action to happen keep the left wrist flat in relation to the back of the left forearm and the back of the left hand. It's as simple as that. When you are hitting the Callaway X-24 HOT Irons, if the left arm is in the correct position the wrists will hinge, if not there will be a breaking motion. Don't try to cultivate an independent wrist motion. Let it be natural. Swinging the club back farther than shoulder turn forces the wrists into a cupping(breaking)position.