How Do You Serve Faster in Tennis?

Serve speed starts at the ground. Your legs and hips get the motion going and your arm finishes it, so the training with the best junior evidence is explosive, whole-body work, not more arm work. In one study of nationally ranked boys around 14, six weeks of core, band and medicine ball training added 4.9 percent to serve speed. Here's the simple version of how it works and what to train.

Your arm is the last link

Darren Cahill said it after Jannik Sinner's team reworked his serve in late 2025: "You have control over one shot in tennis, and that is the serve." What they changed, Cahill said, was the serve's rhythm and tempo. Cahill's verdict on the result: "He's actually pumped up the miles per hour."

Think of the serve as a whip. The arm is the tip that cracks, but the crack only happens if the handle moves first. Your legs and hips are the handle. That's why the training below works the legs and hips, not just the arm.

Use your legs

Researchers in Australia had 12 high-performance male players serve with their normal leg drive, then with their legs mostly switched off. Without the legs, racket speed dropped 8 to 10 percent, and the load on the shoulder stayed about the same. Same stress on the joint, less speed.

Leg drive may also protect you. A review by Bruce Elliott, a longtime tennis biomechanics researcher, found that "players with more effective knee flexion-extension during the service action were associated with lower loading at the shoulder and elbow." Muscling the ball with your arm makes your shoulder work just as hard for a slower serve.

Train fast, not heavy

The junior studies point one way. In the six-week study above, 30 boys took part. Half added three sessions a week of core, elastic band and medicine ball work, and that group gained 4.9 percent. The half that kept to normal tennis training gained 0.2 percent. In an eight-week study of 36 teenage boys, jump and throw training added 3.8 percent. Machine weights didn't make a significant difference. Serve accuracy didn't change in any group.

So keep it simple, two or three times a week: medicine ball throws, rotating and overhead, light enough to throw hard. Jumps. Light band work for the shoulder. Every rep fast.

Protect the shoulder

Extra speed also has to be slowed down by the muscles at the back of your shoulder. Keep training them with light bands, even after the speed shows up. It's the boring work that keeps you serving, the same lesson Nick Kyrgios learned the hard way.

Strength training is safe for juniors when it's done right. The American Academy of Pediatrics says well-designed programs have "no apparent negative effect on linear growth, physeal health, or the cardiovascular system," and that injury rates with qualified supervision and proper technique are lower than in other sports or recess. Have a coach or trainer watch your form.

Speed is a number. First serves are points.

Sinner's rebuilt serve paid off in the percentage, not just the speed. Through the Miami Open in March 2026, he made 67.5 percent of his first serves, up from 61.9 percent in 2025, and won 81 percent of those points. A first serve that lands wins more than a fast one that doesn't, which is the same lesson behind the shots that actually win junior matches.

Put more first serves in and let the speed come. Train the chain, protect the shoulder, then chase the number.