Knee bend in the tennis serve
Checkpoint 4 of 9 Measured by Serve Scan
Knee bend is how your legs load before the swing: your knees bend and your hips lower as the ball goes up, storing energy you release upward into the ball.
Your serve speed starts in your legs. Bending your knees and lowering your hips as the ball goes up stores energy that you release upward into the ball. Without it, your arm has to do all the work.
What good looks like
- Knees bend as the toss goes up
- Hips lower, weight stays over your front foot
- Deepest bend at the trophy, just before you swing
Common faults
- Straight legs all the way through
- Bending at the waist instead of the knees
- Bending early, then standing up before the swing
Drills to fix your knee bend
- 1
Load and launch
As the toss goes up, bend your knees and hold the bend for one second, then push up toward the ball.
3 sets of 8 shadow serves, then 10 serves at half pace
- 2
Toss, sink, catch
Toss, sink into your trophy, then push up and catch the ball with your tossing hand at full stretch above your head.
3 sets of 8
- 3
Up, down, up
Say it out loud as you serve: “up” as the toss goes up, “down” as your knees sink into the trophy, “up” as you drive into the ball. The rhythm puts the bend in the right moment.
3 sets of 6 serves
What your body is doing
Quads, glutes and calves load like a spring.
Watch Pavel explain it
Plays from YouTube.
How to practise it
- Watch the video first. Then copy the drills slowly, without a ball.
- Practise little and often. Five to ten minutes before each session, for two weeks.
- Add the ball at half pace. Keep the feeling for 10 to 20 serves before you build up speed.
- Check your progress. After two weeks, film one serve side-on and scan it again to compare.
Is your knee bend right?
Film one serve on your phone. Serve Scan tracks your body, scores your knee bend and the rest of your serve out of 100, and shows where it leaks power. Free, and your video stays on your phone.
Questions
What is the knee bend in a tennis serve?
Knee bend is how your legs load before the swing: your knees bend and your hips lower as the ball goes up, storing energy you release upward into the ball.
What are the most common knee bend mistakes?
Straight legs all the way through. Bending at the waist instead of the knees. Bending early, then standing up before the swing.
How can I check my knee bend?
Film one serve side-on with your phone at hip height and your whole body in frame, then run it through Serve Scan. It measures your knee bend with body tracking and scores it, free.
How long does it take to improve?
Practise little and often. Five to ten minutes before each session, for two weeks. Check your progress. After two weeks, film one serve side-on and scan it again to compare.