Movements before the serve

Hi Alois

I've been wondering why some players do something during the serve.

Before Micheal Maze tosses the ball, he moves his bat up like in the clip for what?

http://www.youtube.com/watch?v=YCkvafkxAV4 at 0.36 

In the same clip, at 0.14 After Mizunati tosses the ball, he moves his hand down and up and then hit the ball. What does he do that for? 

Thank you for the answer in advance. 

Hi Itiipat,

They are both just a part of their service action.  It can tend to free up your arm and relax it a little but it isn't a necessary part of the serve.