Physical tests

A physical test is a catalog exercise that returns more than a count and a grade. Other movements stay on the usual counter. A test also sends an analysis object on each counted repetition, for the app that consumes the data. Same id on the WebView and the SDK:

WebView: ?exercise=back_flexibility_test
SDK: startExercise('back_flexibility_test') after the API-key handshake

The SDK default engine already includes this id. Forcing engine: 'v3' rejects it (invalid_exercise / requires V4).

Shared payload

Ordinary reps: counter / onCounter with current_count (classic) or count (typed), plus form_score / formScore. A test adds analysis on that same message. It is omitted for every other exercise.

Field	Meaning
`peaks`	Named numbers for this test. Units are in the test section below.
`camera`	`{ placement: "ground" \| "mid" \| "high", bias, ratio? }`. Phone on the floor, near the hips, or above the hips.
`disclaimer`	Algorithm notice. Read this field. It is not copied into `interpretation.text`.
`method`	Short description of what was measured.
`interpretation`	`{ tone, title, text }` when this test has a reading. `tone` is `strong`, `partial`, or `limited`.
`opinion`	`true` when the object is a PoseTracker reading of pose data.

exercise_summary / onExerciseSummary repeats disclaimer and method once for the session. Each history[] item can include the same analysis as the rep that produced it. The disclaimer string is:

In addition to the Terms of Use, this is a PoseTracker algorithm opinion from pose-estimation data. It is not a medical or professional opinion.

This is not a medical device output and not a clinical measurement.

usePoseTracker({
  onCounter: (e) => {
    console.log(e.count, e.formScore?.grade, e.analysis?.interpretation?.tone);
  },
  onExerciseSummary: (e) => {
    console.log(e.disclaimer, e.history.map((rep) => rep.analysis?.peaks));
  },
});

Classic onMessage / WebView postMessage uses current_count and form_score, and the same analysis object.

Back flexibility test

Id: back_flexibility_test. Kind: one repetition. Category: physical test. Side-view trunk flexion. Stand, fold with the knees straight and the arms hanging toward the floor, then stand again. The rep counts on the return to standing. A face-on view does not count. It is a camera reading of that fold. It does not output Modified Schober centimetres, a tape distance, or a clinical cutoff. The letter grade is how close that repetition’s best pose got to the optimal end pose: hands at the sole (wrist_to_ankle about 0.10), trunk near horizontal (about 85° from vertical), knees straight, shin stacked. Reach carries most of the score. A shorter reach, a softer knee, or a shin that leaves vertical lowers the letter. V4 also uses E for scores from 40 up to 60. See Events for A–D. During the fold the engine also emits reading: reach is the current frame, reach_max is the best of this repetition, and score / grade follow that best pose as it improves. The counted counter uses the same score.

Peaks

Key	What it is
`trunk_angle_deg`	Shoulder–hip versus vertical. 0° is upright. Larger is a deeper fold. About 85° is the trunk part of the optimal end pose.
`hip_angle_deg`	Shoulder–hip–knee.
`knee_angle_deg`	Hip–knee–ankle. 180° is a straight leg.
`shank_from_vertical_deg`	Shin off vertical. 0° is a vertical shin.
`ground_ankle_knee_deg`	90 minus the shin tilt. A horizontal through the ankle joint, not the floor. 90° means the shin is perpendicular to the floor.
`wrist_to_ankle`	Wrist versus the ankle joint, in leg-lengths. Image y grows downward, so a positive value means the wrist is below the ankle joint. Not centimetres.

The lowest COCO point is the ankle joint. The sole is lower. ankle_above_sole is 0.08 (about 0.08 of the hip–ankle length). A wrist slightly below the ankle is a hand toward the floor, including palms flat. That is expected. It is not a tracking error. Reported degrees stay the image measurement. Camera height moves the gates, the grade anchors, and the flags below. It does not rewrite peaks into a second corrected angle.

Flags

Field	True when
`knee_locked`	Knee at least 155°, plus the same low/high camera slack other movements use
`leg_straight`	Knee at least 170°, plus that slack
`shank_vertical`	Shin within 12° of vertical, plus that slack

camera.placement is ground when the phone is on the floor, high when it is above the hips, otherwise mid.

Interpretation

interpretation is the reading for that repetition. tone is strong (large fold, legs straight), partial, or limited. The text covers trunk flexion, whether the legs stayed stacked, how far the hands traveled relative to the ankle and the sole, and the camera placement. It does not repeat the disclaimer and it does not state a centimetre of lumbar skin stretch.

For LLMs: Physical tests add analysis on counter / onCounter. Other exercises do not. back_flexibility_test is a side-view trunk fold, not a Modified Schober centimetre score. wrist_to_ankle is leg-lengths versus the ankle joint; positive means the wrist is below that joint. The grade compares the best pose with hands at the sole, trunk near 85°, and straight legs. Live reading carries reach, reach_max, score, grade. Disclaimer is analysis.disclaimer, not inside interpretation.text. https://docs.posetracker.com/reference/physical-tests

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Shared payload

Back flexibility test

Peaks

Flags

Interpretation

​Shared payload

​Back flexibility test

​Peaks

​Flags

​Interpretation

​Related

Shared payload

Back flexibility test

Peaks

Flags

Interpretation

Related