"Pre-Cock Wrist Drill."
The purpose of this drill is to help you learn the correct action of the wrists during Symple Swing.
Set up normally at address. Then SLOWLY "thumb cock" your front wrist. Thumb cocking means bending your wrist in the direction of your thumb, making sure of course that the back of your lead wrist stays flat. (By lead wrist we mean the left wrist for a right handed golfer) While you thumb cock your wrist your arms should stay absolutely still. Then when your wrist is fully "thumb cocked" you turn your shoulders and make your swing. You are in effect pre-cocking your wrist and then making your swing.
Some folks won't have a big thumb cock at all. I'm not very flexible so I can only "thumb cock) about 45 degrees. YOU DON'T NEED A BIG THUMB COCK. When doing this keep the lower body quite still we just want to isolate the shoulder turn. Make sure you KEEP THE LEAD ARM STRAIGHT.
The pre-cocking should help you feel what the proper position of your wrist at the top of the backswing should be like. Don't worry if your backswing seems a little more compact, that's normal. Take some practice swings. Then hit some half shots, then some 3/4 shots and then some full shots.
When practicing stop at the top of your backswing, turn your head and look at the position of your lead wrist. It should still be flat. If it cups (bends towards the top of your forearm) then the club is coming off plane and you'll have to reroute the club on the downswing which adds complexity to your swing and reduces consistency.
There one more thing I'd like you to concentrate one. I'd like you to stick a long tee in the butt of your club. Then as you make slow motion backswings and downswings I'd like you to make sure the "tee" points to the extended target line (The line that extends from the target through the ball and continue back). If the tee points at the extended target line during backswing and downswing it means you are on plane and that will mean straighter shots.
Note: We do have some folks who play only occasionally who actually integrate the Pre-Cock Drill into their normal swings. They feel that pre-cocking means the are less likely to screw things up at the top of their backswing. They believe since they only get to play occasionally that pre-cocking is simpler for them giving them one less thing to think about during the swing.