Why do people think they can roll over the ball?
This is physically impossible the ball stays on the racket 3.2 milli-seconds on the face the racket, the strings needs to be vertical traveling from low to high in order that is the ball has topspin. This is a myth for most tennis players you can’t roll the head of the racket as you contact the ball. This will make the ball travel into the ground. The contact must be square so the strings are flat for the ball to stay in.