Originally Posted by user92626
It sounds like you're trying to split a stroke into different, individual components, ie. " closed racquet face by itself" and pick parts to argue!!! Why? A stroke needs a right mix of stuffs to work, ie the power, the contact, the path, ... and you hone in by practicing and feels.
"The best way to get the upward component is the ww stuff, pronation, etc."
Well, for me the best way to get the upward component is to ...hit up
What I observe is that human mind can only visualize and apply exerting force in a linear path
. Yes, in reality the racket goes in an arc, but when you intend to hit or throw something with force it's a linear, "straight" line exertion that the mind perceives. So, when you think pronation, ww or anything that goes in a curve, especially after the initial swinging, it tends to screw up your stroke.
I'm not trying to pick parts to argue. I also agree that you can only focus on so many things at one time. To me, closing the racquet face is the last thing you think about. If the swing path is right and the form is good, but the ball is still long or into the net, change the racquet face angle. Estimating the best racquet face angle is something we do on every shot and had lots of different components that affect what the best angle should be.
But I did want to address the idea that closing the racquet face in and of itself produces topspin. To me this is the wrong place to focus if you're trying to generate more topspin. I'm just imagining folks going out, tilting their racquet face more toward the ground, and wondering why they're not getting anymore topspin and hitting the ball into the base of the net.
If you want the big topspin, the racquet has to have a large upward component to its velocity that is perpendicular to the ball. That's just physics - like you said swing up. Given human anatomy, the way that high level players are creating this huge upward velocity (i.e. swinging up), while maintaining good forward velocity through the ball, is via pronation of the forearm and upper arm rotation. You can say it's wristy, hard to learn, whatever, but I know of no other way to make this happen.
You can get smaller amounts of topspin by hitting with a rising swing path. Swing low to high and catch the racquet up by your head. It works for what it does, but again you're not going to get the huge topspin, ball goes 70 mph and kicks up to your opponents head, with that technique.