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Technical Details

  • Variable Type: Event
  • Data Type: Integer
  • Units: Frame number
  • Column Name: seat_off_frame
  • Required for QA: True
  • Recurring: One frame per repetition
  • Measurement: Last frame before the rise at which the pelvis is within 10% of the repetition’s rise amplitude above the low point the rise starts from

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Description

Seat Off marks the moment the person leaves the chair and begins to stand. It is detected from the vertical trajectory of the hip center (pelvis keypoint), smoothed with a 0.1-second moving average. For each repetition, Uplift finds the low point that the rise starts from and takes the last frame within 10% of the rise amplitude above that low point. Because the threshold is referenced to each repetition’s own low point rather than a single seated height for the whole capture, touch-and-go repetitions that bottom out slightly above the chair are still detected. Seat Off starts the Rise phase. Per-repetition metrics are stored at each repetition’s Seat Off frame.

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Use Cases