First, you learn nothing by being a jealous troll. Period. "You can't teach tennis to an empty box."
Hogwash or BS. to the above.
All ATP players serve with pronation. I won't tell you twice, visit Pete Sampras. See for yourself. It's so easy to be a critic but not as easy to learn. Especially learning correctly. And some of you make the learning process more difficult than it has to be.
See if you can get a copy of a book by the late and great Pancho Gonzales, published in 1965. Probably second printing?
My grandfather introduced me to tennis. He also purchased tennis books, lots of books. I was just about 8 years old when I started playing. We would look at the pictures constantly. I noticed in two photos the rotation of the racket head, before then after ball contact. PRONATION! I studied it and finally figured it out without the help of anyone but my grandfather!
I looked on line. You can see Pancho Gonzales serve in full view. And if you can't see the pronation, same with Sampras' serve, you have an extraordinary problem and are beyond conversation or help. Hey! I don't have to be here.
The "book." I would study the photos in the books I had because my grandfather always said, "play like the pros." And yes, he said this often. He was a great man and my only male inspiration in life as a young kid growing up.
Most of you haven't been playing tennis long enough and you have no idea what you missed and weren't part of. It's sad actually.
I'm not going to say another word about service pronation and it's not because I'm being trolled, it's because there's nothing more to say about it.
Yesterday I participated in the training of a junior who is #1 in his state. What did you do yesterday? Today I'm helping a player learn pronation.
Well, I see I cannot post photos so you're on your own. "Stills" are better than video.
Here's a player serving. Doing a few things I would change but at least the pronation is there.
tt.tennis-warehouse.com/index.php?threads/maxtennis-serve-practice-videos.681685/
A quick note.
Poncho Gonzales was 6'2" tall. His serve was 112 MPH. Keep in mind this was the 40's, 50's and 60's. He played a wooden racket then eventually used a metal one.