Trying to hit a tennis ball “hard” often results in decreased ball speed because you tense your grip and try to swing with just your arm. Players who rely primarily on their arm for hitting powerful tennis shots often grip the racket too tight, resulting in tense muscles, which decelerates the swing. Use your lower body and torso to accelerate your racket and hold a looser grip to swing fast and hit more winners.
Swing easy, hit hard for powerful tennis shots.
Stand on the baseline and face the fence behind you. Bounce balls in front of you and practice hitting balls into the fence. Finish your swing with the racket ending above your opposite shoulder. Your goal should be to touch your back after each swing. Finish a forehand with the biceps muscle of your hitting arm near your chin. Finish a two-handed backhand with the biceps of your trailing arm near your chin. Finish a one-handed, topspin backhand with your hitting hand above your hitting shoulder.
Use Your Legs
Practice bending your knees as you take the racket back, then pushing upward, off the ground, as you swing forward. The reason coaches tell you to bend your knees is because the push upwards that follows accelerates your racquet and produces power and speed. Hit several balls with your pinky off the handle to practice hitting with a relaxed grip so you can focus more on your legs.
Open Your Hips Earlier
Don’t turn your body as a single unit when you hit hit the ball. Practice opening your hips slightly before you open your torso as you push upward and swing forward. This is a key difference in the power generation between professional male and female players, notes Dr. Ben Kibler of the U.S. Tennis Association sports science advisory committee in his article, “The 4,000 Watt Tennis Player.”
Gradually Add Length
Stand on the service line facing the net and practice bouncing and hitting balls over the net with these stroke corrections you just practiced into the fence. Have a partner feed balls to you from the opposite service line. Next, stand halfway between the service line and baseline and have your partner feed you balls from the opposite baseline. Practice swinging the racket with your new techniques, paying particular attention to your finish over your shoulder. Finally, stand at the baseline and practice your strokes. Note your racket finish and if your weight is moving forward as you hit shots. Exaggerate your early hip rotation if your weight is not shifting onto your front foot before you begin your forward swing.
Use Low-Compression Balls
Practice with low-compression balls (the multi-colored kids’ balls). Hit from baseline to baseline until you can sustain a rally with a partner, playing all balls on one bounce. This will take a very high swing speed because it’s difficult to hit these balls baseline to baseline.
Next, hit with regulation balls, noting your increased swing speed and full follow-through. Allow balls to go long at first, working to bring the ball back into play with a full swing, rather than shortening your swing. Repeat the process of hitting with foam or low-compression balls for several minutes, then regular balls, three times each practice.