Technical Details
- Variable Type: Discrete Metric
- Data Type: Float
- Units: N/A (ratio/factor)
- Column Name:
twist_pelvis_trunk_speedup - Measurement: Ratio (or factor) of Peak Pelvis Twist Angular Velocity to Peak Torso Twist Angular Velocity
Description
Twist upper arm forearm speedup quantifies the increase in peak twist angular velocity from the upper arm to the forearm during the serve. A value greater than 1 indicates the forearm reaches a higher peak twist angular velocity than the upper arm, completing the optimal Twist Kinematic Sequence (pelvis → torso → upper arm).Use Cases
- Twist kinetic chain and energy transfer
- Technique quality (proximal-to-distal speedup)
- Coaching and training feedback