Originally Posted by toly
I checked a lot of videos of different serves and different players. I failed to find any serve with rising ball.
Your examples are optical illusions.
Take another look at the video above. Note the position of the ball at contact with respect to the top of the frame at the 0:33 mark. After the ball has left the racquet, it moves upward out of the frame. The camera position does not move. How is this an illusion? If you can't find other examples, you just are not looking hard enough.
Not so sure that the image sequence from CharlieF is an optical illusion either. It's hard to say for sure. The camera position/perspective does not change. The ball appears to rising in this example. If anything, this camera perspective tends to disguise/minimize the amount that the ball is rising. If this was shot at an angle that is parallel to the court and close to the height of the contact, we would see that the ball actually rises more than this sequence of images would seem to indicate.
Granted, there are probably plenty of players who can hit a flat serve such that the ball starts to drop as soon as it leaves the racket. It may be something of a myth that the server must be 6'9" (206 cm) or taller to accomplish this. However, probably only a very small percentage of players can hit a twist or other kick serve that does not rise when leaving the racquet.
Your example that shows a twist serve, hit with a closed racquet face, with the ball falling as it leaves the racquet does not apply to most servers. For a kick/twist serve, I am not sure if it is possible to hit the ball with a closed face and have the ball rise. Many players may actually hit it with a neutral face or one that is somewhat open.
In his TWU article, Rod Cross claims that a kick serve must be hit at about 100 mph. This is not
a requirement for hitting for hitting a kick serve at all. Most servers hit their kick serves well under 90 mph (even well under 80 mph). Clearly, the kick serve that he speaks of is one that very few players can actually hit. Rod later amended his stance on this and admitted the kick serves did not need to bit hit close to 100 mph.
Take a gander at the following video from Pat Dougherty (the "Serve Doctor"), who is a serving guru with the Bolletierri Tennis Academy. At the 1:24 mark in the video he says the ball must first go up and then come down sharply for an effective "sick kick".