90 degree angle in arm

Can i use the 90 degree angle of my forearm in the backswing only for the topspin against backspin?

Hi Swaraj,

With the forehand topspin, the 90 degree angle we refer to is for the finish position. Watch the Forehand Topspin Against Block video to see Alois explain this. For the backswing you can start with a fairly straight arm or have it slightly bent, this is a matter of preference and style.