Forward Swing
Every drill up to this point has been done to get into a solid hitting position and to build, in segments, momentum for the forward swing. Now you’re ready to hit. The forward swing is a chain reaction of movements that started with your footwork.
Taking a horizontal swing path with the racket face perpendicular to the court is okay for beginners. Even world-class players flatten the trajectories of their swings when they want to hit hard and flat.
Otherwise, the swing is forward and upward, brushing the back of the ball. The more vertical the swing path is, the more topspin is put on the ball. Topspin is good for control, consistency, and making the ball bounce high on the other side.
Keep your head still, hold the racket with a firm grip, and make contact early. Wrist action is more significant in today’s strokes than in the past. A traditional Eastern forehand grip requires a relatively fixed wrist position for most shots, but players who use a Western or semi-Western grip put a lot of stress on the wrist and forearm as they whip upward and across the back of the ball. Try to make contact before the ball reaches a position that is even with the midsection of your body. Some teachers advise hitting the ball a foot in front of the body. You can’t always hit that far out in front, but do try.
Tennis: Steps to Success Jim Brown,Camille Soulier