Originally Posted by boramiNYC
saying servers don't actually hit downward when obviously the ball travels downward is a contradiction and not true. the racquet head is controlled and accelerated in such a way at contact the RHS is highest at contact and it's facing the target with desired spin. all these info are directly registered and comes from the servers mind.
you might be able to achieve pretty good serve in a roundabout way but I would contend that's not the optimal way. it could be argued it could be helpful and I agree to that however.
I've seen a very slow motion video of a pro serve that indicates otherwise. Just as the ball has left the stringbed, it travels horizontally (or virtually horizontal) for short time before the ball begins to fall due to gravity & topspin. High speed video also shows the racket still rising after contact even tho' the racket face was slightly closed. I have also witnessed numerous serves (in person) where the ball rises for while after leaving the strings.
Remember that the ball is only on the strings for a few milliseconds. We often see the racket moving downward shortly after the ball has left the strings and incorrectly make the assumption the we have hit down on the ball on the serve.
Whether the ball leaves the strings moving horizontally, slightly upward or even slightly downward (Isner et al), it is probably a mistake to tell students to hit down on the ball for the serve most of the time. There are exceptions -- sometimes we tell a student to perform an action that we know is not quite right in order to elicit a desired response.