inside out pendulum

 

It reminds me a lot of learning to play (for me bass) guitar.  At first it's really akward just having your hand up and under.  Then one day you realize you aren't even thinking about that.

 

The moral of the story is, just keep working on it and you'll get it.

 

The other thing that most of the amatuer videos seem to focus on is the ball rolling back to the net rather than the quality of the serve when it matters: the first two bounces on your opponent's side. Often they bounce way too high and slow across the net and the trajectory is horrible. One of the high level players put it well when he told me that underspin serves should "skid" rather than bounce. That is more of a trajectory related thing and I found a couple of illustrations of different trajectories to show what most amateurs do and what ma lin does (moreso). First is the typical beginner to intermediate underspin serve bounce type; It's high slow and easily pushed back or more advanced players will attack it. Like this:

 

 

A skidding bounce should be more like the red line here:

When it has a more flat trajectory and more speed in the first two bounces on your opponent's side it will be harder to return for a few reasons: it has more energy (to get a flatter trajectory you have to put more power into your swing while keeping a grazing contact and this gives you more speed and more spin),  the opponent has less time and it has a better trajectory. Focus on making those first two bounces on their side have the best quality possible and don't worry if it slides off the end instead of stopping.

 

http://www.youtube.com/watch?v=oT-8iPeHoKg 

 

His services starting at 1:10 have such good deception. I'm jealous