You know the drill (pun intended) - you both stand at the service line and hit groundstrokes to each other. Some people 'cheat' by slowing down their swing speed, or, even worse, changing to a volley grip and 'bunting' the ball upwards with an open racket face. Coach says that in order to do this drill correctly, you should use a normal groundstroke swing path and grips (for me that is western forehand and semi-western 1hbh), you should hit with a closed racket face, and, crucially - you should swing as fast as you possibly can. Seriously, if you do this drill correctly, you should be beating the **** out of the ball, but you should have such a vertical swing path and closed racket face that the ball travels extremely slowly through the air, meaning that all of the racket-head acceleration has been translated to spin, not speed. The extreme topspin you have put on the ball should make the ball drop well before the service box and then explode over the other guy's head when it hits the court. It's then up to him to control it and do the same to you. If you do it this way, it really is a tough drill, and one of the best drills out there for forcing extreme racket head speed and topspin generation. Does anyone else find it tough?