WildVolley
Legend
Yeah, that's what I mean, forward and up. When you go forward and up with a slightly open racquet face, the strings will strike the ball from below the equator of the ball and it can only hit it flat from below the equator of the ball.
To brush when striking below the equator of the ball, you have to pull back towards you a bit.
Just imagine the racket is open 3 degree from vertical and the ball only has a horizontal component as it moves into contact, but the racket is moving up at a 45 degree path (vector).
The ball will start compressing into the strings at 3 degrees below the equator but since the vector of the racket is at 45 degrees, as the ball compresses it will move down slightly against the string as it compresses and the racket pulls up against the outer wall of the ball. As it releases from the string bed it will have topspin.