Originally Posted by sureshs
I see their rackets going up a slope. Why do you say it is a nearly horizontal plane?
Less than 20 degrees is visually closer to an horizontal plane... so, to break with the common knowledge which advocates "low to high" and the impression we have of players hitting very vertically, I use this wording.
They do hit low to high... but it's a very shallow slope for most forehands. Federer is very consistently hitting on something around 16 degrees, unless he purposefully moonballs.