Handling a high ball to the backhand is a tough shot for a lot of players. However, the mechanics necessary for hitting a high ball are pretty similar to “normal” backhand mechanics. A backhand that is about waist high, for example.
To start, figure out what your tennis racket and arm relationship is at contact on a typical backhand. Your hitting-arm position. Take that racket and arm position and “raise it up.” Nothing changes other than raising your contact point. This applies for both a one-handed and two-handed backhand.
One thing that does change, however, is how you swing up to the tennis ball. On a high backhand, the racket doesn’t drop down as much as it would for a typical, “normal height” backhand.
At 1:25 in the video we watch Sacha Jones hitting two two-handed backhands: a normal backhand and a high backhand. The relationship between the tennis racket and her arms remain the same, regardless of the contact height.
At 1:50 in the video we back up her swing a little bit. You can see that, as she swings up to the tennis ball, her racket and hands don’t drop down as low on the high ball as they do on the normal backhand.
At 2:10 in the video we switch to Justin Gimelstob’s one-handed backhand. Just like Sacha Jones, Justin’s tennis racket and arm position relationship remains the same regardless of the height of his contact point. Also, when he swings up to the ball, his swing plane remains higher on the high ball.