| Handedness | N/A | Handedness of the athlete. | “ |
| Stance Position | N/A | Classification of serve stance position. Options are ‘platform’ or ‘pinpoint’ | “ |
| Loading Phase Max Knee Flexion Front Leg | degrees | Maximum amount of front leg knee flexion during the loading phase of the serve | “ |
| Loading Phase Max Knee Flexion Back Leg | degrees | Maximum amount of back leg knee flexion during the loading phase of the serve | “ |
| Loading Phase Trunk Tilt | degrees | Maximum amount of trunk side-side tilt towards the rear during the loading phase of the serve | “ |
| Loading Phase Pelvis Tilt | degrees | Maximum amount of pelvis side-side tilt towards the rear during the loading phase of the serve | “ |
| Loading Phase Shoulder Hip Separation | degrees | Maximum difference in rotation of the shoulders and hips during the loading phase of the serve | “ |
| Loading Phase Ball Release Angle | degrees | Angle between wrist and shoulders at the instance of ball release. 90 degrees would be exactly in front of the non-dominant shoulder, 180 degrees would be sideways completely horizontal. | “ |
| Cocking Phase Max Shoulder External Rotation | degrees | Maximum amount of shoulder external rotation during the cocking phase of the serve | “ |
| Cocking Phase Shoulder Hyperangulation | degrees | Maximum amount of shoulder horizontal abduction during the cocking phase of the serve | “ |
| Acceleration Phase Max Knee Extension Velocity Front Leg | degrees/second | Maximum knee extension velocity of the front leg during the acceleration phase of the serve | “ |
| Acceleration Phase Max Knee Extension Velocity Back Leg | degrees/second | Maximum knee extension velocity of the back leg during the acceleration phase of the serve | “ |
| Contact Phase Elbow Flexion | degrees | Amount of elbow flexion at apex | “ |
| Contact Phase Shoulder Abduction | degrees | Amount of shoulder abduction at apex | “ |
| Contact Phase X Factor | degrees | Angle between the shoulders to hips in the transverse plane (twisting) at apex | “ |
| Contact Phase Trunk Tilt | degrees | Degrees of side-side trunk tilt at apex | “ |
| Peak Torso Forward Angular Velocity | degrees/second | Peak forward angular velocity of the torso segment in the serve direction | “ |
| Peak Upper Arm Forward Angular Velocity | degrees/second | Peak forward angular velocity of the upper arm segment in the serve direction | “ |
| Peak Forearm Forward Angular Velocity | degrees/second | Peak forward angular velocity of the forearm segment in the serve direction | “ |
| Kinematic Sequence | N/A | Sequence of peak forward angular velocities. Optimal sequence is ‘torso-upper_arm-forearm’ | “ |
| Contact Phase Wrist Velocity | meters/second | Linear speed of the wrist joint center at apex | “ |
| Contact Phase Wrist Height | meters | Height of the wrist at apex measured from the ground | “ |
| Forearm Forward Angular Velocity | deg/s | Time series values of the instantaneous forward angular velocity (serve direction) of the forearm segment. Evaluate near apex (ball contact event) to visualize kinematic sequencing | forearm_forward_angular_velocity |
| Upper Arm Forward Angular Velocity | deg/s | Time series values of the instantaneous forward angular velocity (serve direction) of the upper arm segment. Evaluate near apex (ball contact event) to visualize kinematic sequencing | upper_arm_forward_angular_velocity |
| Torso Forward Angular Velocity | deg/s | Time series values of the instantaneous forward angular velocity (serve direction) of the torso segment. Evaluate near apex (ball contact event) to visualize kinematic sequencing | torso_forward_angular_velocity |
