Serving deceptive movements

I like Ma Lin's sidespin serve but my question is in general:Why players like Ma Lin after serves sidespin make with the hand another move.It is to confuese the oponent because he is reading the spin?Or to add a extra-spin?

Hi Adrian,

That is purely so that his opponent has more problems in reading the spin on the serve.  After you hit the ball you can not put any extra spin on the ball.