Myth - You should keep your racket head above your wrist on your shots.
Truth - The pros drop the racket head all the time to hit topspin on their forehand and backhand groundstrokes. Yes, the racket head stays higher on the volleys, but that is because you are trying to hit with a slice (imparting a downward punch to make the ball spin backward). Keeping the racket head higher on the volleys will come naturally as you learn how to hit with a little slice on the volley.
Do not force yourself to keep the racket head above the wrist. Doing this will have the affect of making you too rigid and mechanical in your play. This will frustrate your ability to play more instinctive, automatic, and relaxed tennis.
If you have read any of my web site or any of my myth list you should realize by now that I am not a fan of all this excessive technical information. Which serves only to confuse and complicate the whole process of learning. Too much emphasis on the technical leads players to believe they have to do a host of mechanical things correctly before they can play tennis. The emphasis is on the technical information not the repetition that makes the technical work correctly. The emphasis should always, and I repeat, always be on repetition.
When you are too technically oriented you will produce robot like play, not automatic, instinctive, relaxed play. Forcing yourself to Keep the racket head above the wrist along with keeping a firm wrist are two myths that can cause a player to become too stiff and mechanical.
Listen to some of the commands you may hear in a typical lesson and see what you think.
1. Keep your racket above your wrist
2. Keep a firm wrist
3. Stay down on your shots
4. Stay still and balanced after your shots
5. Keep your head down
6. Keep your weight forward
Who plays like that? I don't. Other pros do not either! You go with what the situation dictates. If hitting with your weight moving backward is necessary, that is what you do. If you have to dip the racket head down below the wrist to retrieve a ball, that is what you do!
Thinking and playing like a pro will require you to let go of many traditionally accepted ideas that hamper the natural learning process.