Re: American twist serve
The twist serve is pretty difficult to execute for young players. But after you get the kick serve down, it is actually relatively easy to translate into hitting a twist serve because there is only one key difference, you put a tad bit of sidespin on the ball. While the kick serve only requires upward brushing, the twist serve requires like a "wave" brush. Imagine waving to your friend (a real wave, not a stupid spoiled brat Cali girl Venus Williams wave). If you imagine a ball in front of your wave, you are almost pulling it up and to the side at the same time. You have to imagine your racket is just an extension of your hand and execute that similar motion.
Like I said, if you can perform the kick serve solidly, twist serve shouldn't be too difficult afterwards.
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