How do I get the ball to go at super speed in the tennis on WII Sport?

[angel]

Every now and then it happens but know one knows how to re-create it,it just happens sometimes...
If you don't know what I'm talking about:It is that blue cd-WII Sport.
When you play tennis the ball goes at normal speed but sometimes when you serve it goes really fast...How do I let it do that?

 

[Bob]

when the ball is at its highest point hit it, i can usually get it about 75% of the time

 

[Bob]

when the ball is at its highest point hit it, i can usually get it about 75% of the time