The myth of the Ball trajectory on the serve - part2

I've been quite curious and interested about the trajectory of the ball after impact on a serve. You can see my previous article about the myth of the upward trajectory of the ball after contact on the tennis serve :

http://andrevazpinto.blogspot.com/2011/03/myth-of-upward-trajectory-of-ball-on.html

In fact what I've been discovering on the tennis court with more and more videos is that the trajectory of the ball doesn't depend mainly on the height of the contact point, but is more dependable on the speed and spin of the ball. That is true of course until a certain extent, there are many different variables all working at the same time, like height of contact, position of the racquet, spin, speed, etc.

If you watch the last video of Adam at 200 frames per second, serving from the side view, you can see that the ball right after contact is getting lower and lower. At least, we can say without a doubt that there is a tendency for the ball to drop after contact. Of course some can argue that we can't really see the ball clearly and that we need to increase the amount of frames per second on the video footage so we can be sure.

It is interesting to see the same pattern of the flight of the ball on James's serve recorded at 1000 frames per second:

http://andrevazpinto.blogspot.com/2011/03/james-serves-at-1000-fps.html

When I showed this footage to one of the coaches one question was raised: 'how can we be sure that the ball is not staying leveled or even going up for a millionth of a second after contact before it starts dropping?'

I think that the best answer to that question is that in fact, from physics we know that it is impossible for the ball right after contact to stay at a leveled height. At a microscopic level the ball is either going slightly up or down. If it was true that the ball after contact first goes goes up and then it curves down it would be extremely easy to see that on camera since the arc of the ball would have to be very clear.
We can't forget either that the ball before being hit on the serve is accelerating downward and it is not on a stationary position.
What about the topspin, wouldn't that be able to create that looping of the ball extremely fast right after contact?

That is not possible, first of all it is impossible to create perfect topspin on the serve as J.Yandell has already demonstrated. There is always a side component on the serve and that makes it even harder to believe that the trajectory of the ball on the serve first goes up and then magically drops straight without we being aware of it not even at 1000 frames per second. Every shot we hit with topspin we create a long arc since we have to hit the ball over the net. For us to create a short arc we would have to be very close to the net and compromise substantially the speed of the shot.

There might be a few exceptions (although I haven't witnessed that on the pro game) but in general the trajectory of the ball after contact on the tennis serve is downward for either first and second serves.