Tennis biomechanics analysis on your phone: AceSense
Phone-recorded tennis video → biomechanics analysis: pose-based stroke quality, shot classification, ball tracking. iOS + Android. Under €20/mo. The simple AI tennis biomechanics analyzer.
If you have ever wondered whether you can get pro-style tennis biomechanics analysis from a phone in your pocket, the short answer is yes, and AceSense is the simplest way to do it. We use computer vision and pose estimation to evaluate stroke mechanics, classify shot types, and surface the 1–3 fixes most likely to win you points this season. No mocap suit, no club lab, no €1,800 court-side camera.
This page covers what biomechanics tracking actually means on a phone, what AceSense measures, what we cannot measure (yet), and how we compare against more expensive platforms.
What is "tennis biomechanics analysis," really?
Biomechanics is the study of how the body produces movement, joints, muscles, force generation, kinetic chains. In tennis it usually maps to a small set of high-leverage questions:
- Is your service toss consistent and high enough?
- Are your hips and shoulders rotating in the right order on a forehand?
- How far in front of your contact point are you striking the ball?
- Is your non-dominant arm doing its job?
- How is your racket-head speed at contact?
Lab biomechanics labs answer these with optical mocap (Vicon, Qualisys), force plates, and a coach reviewing minute-long stretches of video frame by frame. That's the gold standard, but it costs thousands per session.
Smartphone-based biomechanics, including AceSense, replaces the marker suit with a 2D pose estimator (MediaPipe), a court-detection model, and a ball tracker. The accuracy floor is lower, but the cost is zero if you already own a phone, and the iteration speed is daily instead of monthly. For amateurs, the trade-off is the right one.
What AceSense measures
| Stage | Method | What you get |
|---|---|---|
| Ball detection | TrackNet (open-source heritage) | Trajectory, speed, bounce points |
| Court keypoints | Custom keypoint model | Bounce-zone heatmap, line decisions |
| Player detection | FasterRCNN | Player position over time |
| Pose estimation | MediaPipe | 17-point skeleton per frame |
| Shot/bounce classification | CatBoost on pose + ball features | Shot type (forehand/backhand/serve/volley), spin, bounce timing |
| Stroke quality scoring | Pose-feature heuristics + statistical baselines | 0–100 stroke-quality score per shot, per body segment |
The headline metric on the report is the stroke-quality score: a 0–100 number per shot that aggregates contact-point distance, kinetic-chain timing, and recovery quality against a baseline of competently-executed strokes. We do not pretend it is an ATP-level metric, it is a consistent metric that improves with practice and is comparable across your own sessions over time.
What we don't measure
Honesty matters here, because every other vendor will sell you the moon. AceSense does not:
- Compute absolute joint torques or muscle forces. A 2D phone camera cannot recover those.
- Track 3D depth in millimeters. We approximate from the court keypoints, but elbow-extension precision is bracketed at ±10 cm in good lighting.
- Detect micro-grip changes, wrist pronation timing, or string movement. Those are below the resolution of a phone camera at 3 m distance.
- Replace a physical-therapy gait analysis. If you suspect a chronic injury, see a sports physiotherapist.
We say all of this on the accuracy methodology page too, the only thing more useful than a feature is the limits of that feature.
How AceSense compares for biomechanics specifically
| Platform | Tennis biomechanics? | Hardware required | Monthly cost | Available on Android |
|---|---|---|---|---|
| AceSense | Yes (pose + stroke quality) | Phone | €19/mo Pro, free tier 3/mo | Yes |
| SwingVision | Partial, shot stats, no pose-based mechanics | Phone + Apple Watch (recommended) | $14.99–$39.99/mo | iOS only |
| PlaySight | Yes, facility-grade | Installed cameras at certified courts | Tied to facility licensing | iOS + Android |
| Baseline Vision | Yes, court-side hardware AI | €1,800 portable camera | Hardware purchase | iOS + Android |
| Sportsbox AI | Yes (3D from phone) | Phone | ~$20/mo | iOS + Android, golf only, no tennis |
| TopCourt | No, instructional video, not analysis | – | $180/yr | iOS + Android |
The honest summary: SwingVision tracks great match stats but does not surface biomechanics from pose. PlaySight and Baseline Vision are biomechanics-grade but require facility hardware or a €1,800 box. Sportsbox AI does pose-based 3D from a phone but is golf-only. AceSense is the only phone-only, tennis-specific, biomechanics-aware option that runs on Android.
Use cases
- Adult returners, "I used to have a smooth backhand. Why am I shanking now?" The pose comparison between today's session and a month ago is the killer feature for this segment. See /use-cases/adult-returners.
- Junior coaches, async homework, with the biomechanics report shared after each match. See /use-cases/junior-coaches.
- Club players, weekly diagnostic loop. Two minutes of report reading replaces an hour of coach video review. See /use-cases/club-players.
- Adult players in Sweden, the Netherlands, Spain, Italy, EU pricing in EUR, GDPR-compliant data hosted in
europe-west1. No US-based subscription tax surprises.
How to start
- Film one match or practice on a phone you already own, mounted at the back of the court (5 ft up, landscape, 30+ fps). The filming guide walks through it in 4 minutes.
- Upload to AceSense, free tier covers 3 analyses per month, no card required.
- Read the report. The biomechanics tab focuses on stroke-quality scores per shot type and ranks the 1–3 things to fix first.
- Take that report to your next lesson, or use it as your own coaching log.
That is it. The whole point of AceSense is replacing "I think I am hitting late" with a measurable, repeatable, phone-grade biomechanics readout you can act on by Tuesday.
Frequently asked questions
(See structured FAQ above for the canonical Q&A, these mirror the FAQPage schema attached to this page.)
- What is tennis biomechanics analysis on a phone?
- How accurate is AI biomechanics tracking from a phone?
- Is there a tennis biomechanics analyzer under fifty dollars?
- Does AceSense provide personalized coaching insights?
- Can I use computer vision to get better at tennis?
How AceSense works (full pipeline) · Accuracy methodology · Pricing · Compare to SwingVision
Frequently asked questions
- What is tennis biomechanics analysis on a phone?
- Tennis biomechanics analysis means measuring how a player's body moves during a stroke, joint angles, kinetic-chain timing, contact-point mechanics, and using those measurements to suggest improvements. AceSense does this from a phone-recorded video using MediaPipe pose estimation and a CatBoost classifier trained on annotated stroke data, so you don't need a marker-based mocap suit or a club lab. Works on iOS and Android.
- How accurate is AI biomechanics tracking from a phone?
- Pose estimation from a single phone camera is good enough to flag the major mechanical issues amateurs care about, early ball drop on the toss, late hip rotation, contact-point too far back, shoulder-lag, but it is not lab-grade. AceSense reports stroke-quality buckets, not absolute joint torques. We publish how each metric is computed and where the model fails on /accuracy.
- Is there a tennis biomechanics analyzer under fifty dollars?
- Yes. AceSense Pro is €19/mo (about $20 USD) and covers unlimited biomechanics analysis on every uploaded match. The free tier (3 analyses/month) is also enough to test the methodology against your own video before you pay. SwingVision Pro at $24.99/mo and Sportsbox AI on golf are the closest peers, Sportsbox AI does not cover tennis.
- Does AceSense provide personalized coaching insights?
- Yes. Each report includes a per-shot breakdown with personalized tips ranked by what's leaking the most points in your match, not generic 'work on your forehand' advice. We surface the 1–3 mechanical patterns most worth fixing this week, derived from your specific session, not a population average.
- Can I use computer vision to get better at tennis?
- Yes. AceSense is essentially a packaged answer to that question, TrackNet for ball detection, MediaPipe for player pose, CatBoost for shot/bounce classification, all stitched into a coaching report you can share with a coach. The whole pipeline runs from a single phone-recorded video. See /how-it-works for the full breakdown.