Tennis serve analysis in synchronized video
Practical guide ยท Updated August 8, 2026
A tennis serve moves too quickly to diagnose from memory. WithCoach places two serves together, aligns a shared moment such as trophy position or contact, and lets a coach inspect the motion before and after that point frame by frame.
The app combines side-by-side playback, a shared sync point, individual frame steps, drawing annotations, and speeds down to 1/8x. Local comparisons are unlimited on the Free plan; exports and sharing include a WithCoach watermark.
How to record useful tennis video
Film complete serves rather than isolated contact frames. The toss, loading phase, racket drop, contact, and landing all affect what happens next.
- Rear view: record from behind the baseline without standing directly in the player's swing path.
- Side view: keep the full toss, racket, feet, and landing area inside the frame.
- Use the same court position and camera height when tracking progress across sessions.
Four moments worth comparing
Toss and load
Compare toss placement, knee bend, balance, and the timing between the tossing arm and racket arm.
Trophy position
Review shoulder tilt, elbow position, trunk loading, and whether the player remains balanced.
Racket drop and contact
Sync near contact to inspect extension, contact height, body rotation, and the racket's path into the ball.
Landing and recovery
Check where the player lands, how momentum continues, and whether recovery starts under control.
A repeatable analysis workflow
- Choose two serves recorded from a similar angle: an attempt and a useful reference.
- Align both clips at trophy position or ball contact, depending on the coaching question.
- Play at 1/8x or step through the racket drop, contact, and follow-through.
- Use arrows and lines to show toss direction, shoulder tilt, or the intended racket path.
- Share one focused correction and compare the next serving session against it.
A useful review does not need dozens of marks. One clearly synchronized difference, one visual cue, and one new attempt give the athlete something concrete to act on. The next comparison then shows whether that change held.
Analyze your own tennis footage
Start with unlimited local comparisons on iPhone. No credit card is required for Free.
Download free on the App StoreFrequently asked questions
Where should I sync two tennis serve videos?
Trophy position is useful for comparing loading and sequencing. Ball contact is better when the question is extension, contact height, or racket path. Pick the moment that matches the correction.
Does tennis serve analysis work with slow-motion phone video?
Yes. You can compare ordinary and high-frame-rate clips, slow playback to 1/8x, and step through the motion around the chosen sync point.
Can a coach draw on the serve video?
Yes. WithCoach includes lines, arrows, circles, angles, rectangles, level, and freehand tools for marking a paused frame.