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Technical Details

  • Variable Type: Discrete Metric
  • Data Type: Float
  • Units: °
  • Column Name: arm_slot_angle
  • Aggregation: mean
  • Precision: 0
  • Measurement: Abduction angle of arm (shoulder to wrist) at ball release
  • Reference: Vertical (adducted) = 0°
  • Typical Range: 39 – 63 °
  • Optimal Direction: N/A — depends on pitching style

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Description

Arm slot angle measures the abduction angle of the arm (from shoulder to wrist) at ball release compared to vertical (adducted, 0°). Sidearm and submarine throwers have larger arm slot angles than overhand throwers. A perfectly side-arm release has an arm slot angle of 90°. Uplift’s arm slot categories broadly follow an article from Graeme Lehman: Do Different Arm Slots = Different Mechanics? https://treadathletics.com/arm-slot-differences/

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Normative Ranges

Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.

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Use Cases

  • Arm slot classification
  • Release angle assessment
  • Pitch consistency tracking