J2Pro Motion: the serve, measured stage by stage.
J2Pro Motion is the biomechanics tool Geoffroy Dupuis uses to turn a slow-motion serve video into a clear report: the 8 stages of the serve, the kinetic chain from the legs to the racket, and a short list of priorities for the next training block.
The serve is a whip, not an arm.
Think of the serve like cracking a whip: the power starts in the handle — the legs and hips — and travels to the tip. When one link of the chain is late or missing, the arm and the shoulder pay for it. J2Pro Motion shows where the chain breaks, so the work on court targets the cause, not the symptom.
Objective, not guessed
The key positions are anchored by the coach on the video. The report only states what the camera can really see — nothing is guessed.
Performance and prevention
Footwork and trophy-position load are read against the research on shoulder and elbow stress, to protect young players while they build speed.
Consistency over one good serve
Three to five serves are compared. A technical change only counts when it holds across repetitions.
A plan, not a pile of numbers
Every report ends with strengths, priorities and session outcomes that feed the player’s training programme.
8 stages, 3 phases.
J2Pro Motion follows the 8-stage serve model of Kovacs & Ellenbecker, grouped in three phases: preparation, acceleration and follow-through. The stages in green are anchored by the coach on the video.
What a J2Pro Motion report contains.
Each section is linked to the scientific reference it comes from, so the player, the family and the staff can see why a priority matters.
The question came from an agent.
A WTA-ranked player’s agent asked: is there a fault in the kinetic chain of her serve? The answer, in 7 pages: no fault — 9 checkpoints confirmed, 3 reported as observations to confirm, 2 not reported because a rear camera cannot see them. Read the full case study →
A phone, a side view and one serve.
The best results come from a simple setup. The analyzer asks for the player’s dominant hand, height, stance, serve type and frame rate, and adapts the report to the camera view.
- Film from the side, player fully in frame
- Slow motion: 240 fps is ideal, 480–960 fps for an even finer contact
- One serve per video; 3 to 5 videos for the consistency report
- Optional: scale calibration and a Baseline Vision session summary
Where the report goes next.
J2Pro Motion is used by Geoffroy Dupuis in his coaching work. It is not sold as a separate app. The report becomes goals and sessions in the player’s J2Pro Circuit app, and the next analysis measures the change.