Whistle Physics Contact measurement · Los Angeles

Future of officiating

A physics layer for the calls referees still make by eye.

Whistle Physics measures every contact in a basketball game so judgment calls can be reviewed, graded, and taught with evidence.

Contact the founder hello@whistlephysics.com
Contact event · t₀ Simulated
Two skeleton figures at a contact moment A driving player's lead arm meets a defender's chest. The defender's head moves back more than the contact force would predict. displacement
Initiation 0.81
Magnitude 0.14
Response fidelity 0.22
reason: contact impulse small; torso displacement 4x expected; reaction onset 180 ms late
01 / Measure

What we measure

Every collision, scored on three axes from skeletal tracking.

  • Initiation

    Who created the contact

    Scored from each player's approach velocity and where the bodies meet.

    approach velocity · contact location
  • Magnitude

    How hard

    How much force the contact carried, from the implied impulse at the moment of collision.

    implied impulse · contact proximity
  • Response fidelity

    Did the reaction match the force

    Whether the body's reaction matched the force, from the displacement and timing of each body's response.

    post-contact displacement · reaction latency · verticality
02 / Method

How it works

Physics features feed the model, so every verdict comes with a reason a person can check.

  1. Skeleton tracking

    Pose for both players at the contact moment. We run on broadcast video today; the pilot brings the arena feed.

    • approach velocity
    • contact proximity
    • displacement
    • reaction latency
    • verticality

    Physics features

    Approach velocity, contact location, implied impulse, and the displacement and timing of each body's response.

  3. Last Two Minute reports2015–
    Coach's challenges2019–
    Labelscorrect / incorrect

    Graded model

    Trained against a decade of publicly graded NBA officiating decisions.

  4. reason: contact impulse small; torso displacement 4x expected; reaction onset 180 ms late

    Readable verdict

    Each score ships with its reason, which is what a fine, a grade, or a training rep requires.

03 / Users

Who it's for

League officiating operations First

Review desk
Post-game flop and foul-bait review.
Full-game grading
Every contact, graded at the same standard as the L2M report.
Crew consistency
Whether one crew calls the game the same way as the last.
Training reps
Real contact plays with ground truth and instant feedback.

Teams

Challenge support
Decision support for the coach's challenge.
Contact scouting
Opponent contact scouting from the same event data.

Medical staffs Roadmap

Contact exposure
Per-player collision exposure and landing mechanics.
04 / Status

Proof-of-concept in development on public data. Applying to NBA Launchpad 2027.