Myth - You should move your body weight into the ball on all of your shots.
Truth - I have seen players struggle with this one for many years. They hit the ball as they are moving backward, miss the shot and exclaim, "I should have been moving into the ball!" Of course it would have taken a super human effort to move your weight forward as the ball your opponent hit is driving you backward. Nevertheless it says right here in "How to Play Tennis in a Minute," chapter 5on page 234 that your body weight should move into your shots. By the way, that was a fictitious title I made up. I can hear the wheels turning in your mind, "How to Play Tennis in a Minute," I wonder where I can buy that book?
What do the pros do? Simple! If the shot requires the body to move backward that is what they do they move backward. If the shot requires the body to move sideways that is what they do they move sideways. And yes, if the shot requires the body to move forward that is what they do they move forward. The pros move their body weight according to the situation. You should do the same.
Stop stressing yourself out every time you do not move your body weight into the ball. Allow yourself to move backward, sideways, and forward depending on the shot at hand. Relax and flow naturally rather than being rigid and mechanical trying to force something that is not there. Every shot does not require your body weight to be moving into the ball.
Now, doesn't that feel better already!