As a base line player, I like to hit my ground strokes in a way that provides disguise and produces accurate placement. Hitting the ball with topspin -- swinging upward across the back of the ball -- allows me to do both.
It wasn't too long ago that people like Arthur Ashe, Ken Rosewall and my countryman, Jan Kodes, were very successful with flat, underspin drives. As the game began to move to slower surfaces, ground stroke styles changed; players needed more control because the rallies were longer and underspin drives were not as effective.
Today, most pros use topspin on their strokes. It allows a base line player the choice of safely hitting high or aggressively stroking a ball close to the net. I prefer to hit a lower topspin because it allows me to go for winners. Some players hit higher topspin and patiently rally with an opponent to force a mistake.
The spin is effective on all court surfaces. Bjorn Borg won at Wimbledon on grass, Manuel Orantes won at the U.S. Open on cement and I captured my biggest victory at this year's Volvo Masters on indoor carpet.
When hitting the forehand, use an eastern or semi-western grip. Start the racket head lower than the bouncing ball and drive firmly through it--from low to high. A stand clock reference may help; hit at 6 and finish at 11. Always end the shot well out in front of your body.
Hitting topspin off the backhand is much the same; make sure the racket head is lower than the ball. Use a regular backhand grip.
Whether stroking a forehand or backhand, it is important to make contact with the ball in front of the body, right above the forward knee. Good topspin shots will let you keep the ball in play with less margin for error.