Technical Details
- Variable Type: Discrete Metric
- Data Type: Float
- Units: N/A (ratio/factor)
- Column Name:
forward_trunk_arm_speedup - Measurement: Ratio (or factor) of Peak Upper Arm Forward Angular Velocity to Peak Torso Forward Angular Velocity—how much the upper arm speeds up relative to the torso in the serve direction
Description
Forward trunk arm speedup quantifies the increase in peak angular velocity from the torso to the upper arm during the serve. A value greater than 1 indicates the upper arm reaches a higher peak forward angular velocity than the torso, supporting efficient Forward Kinematic Sequence (torso → upper arm → forearm).Use Cases
- Kinetic chain and energy transfer assessment
- Technique quality (proximal-to-distal speedup)
- Coaching and training feedback