Dimensions
Required Inputs for processing:- handedness: the handedness of the player [‘left’, ‘right’]
- serve stance position: the stance type used for the serve [‘pinpoint’, ‘platform’]
Phases of the serve
Stages adopted from Kovacs & Ellenbecker, 2011. ( Video )| Phase | Stage | Start | End | Event or Phase |
|---|---|---|---|---|
| Preparation | Start | Initiation | Initiation | Event |
| Preparation | Release | Initiation | Ball Release | Phase |
| Preparation | Loading | Ball Release | Low Arm | Phase |
| Preparation | Cocking | Low Arm | Max Sho ER | Phase |
| Acceleration | Acceleration | Max Sho ER | Ball Contact | Phase |
| Acceleration | Ball Contact | Ball Contact | Ball Contact | Event |
| Follow Thru | Decceleration | Ball Contact | Termination | Phase |
| Follow Thru | Finish | Termination | Termination | Event |
Variables
Output variables from tennis overhand serve analysis.Events
| Metric | Description | Column Name |
|---|---|---|
| Initiation | the start of the tennis serve | initiation_event |
| Ball Release | the estimated timing of ball toss release | ball_release_event |
| Low Arm | the low point of the dominant arm prior to ball contact | low_arm_event |
| Max Shoulder ER | the instant of maximum shoulder external rotation between ball release and apex | max_shoulder_external_rotation_event |
| Apex | maximum height of the dominant-side wrist joint center during the serve | apex_event |
| Termination | end of the tennis serve | termination_event |
| Peak Forearm Velocity | the instant of peak forearm forward angular velocity, used to determine forward kinematic sequence | “ |
| Peak Upper Arm Velocity | the instant of peak upper arm forward angular velocity, used to determine forward kinematic sequence | “ |
| Peak Torso Velocity | the instant of peak torso forward angular velocity, used to determine forward kinematic sequence | “ |
Forward Kinematic Sequence Metrics
| Metric | Units | Description | Column Name |
|---|---|---|---|
| Peak Torso Forward Angular Velocity | degrees/second | Peak forward angular velocity of the torso segment in the serve direction | peak_torso_forward_angular_velocity |
| Peak Upper Arm Forward Angular Velocity | degrees/second | Peak forward angular velocity of the upper arm segment in the serve direction | peak_upper_arm_forward_angular_velocity |
| Peak Forearm Forward Angular Velocity | degrees/second | Peak forward angular velocity of the forearm segment in the serve direction | peak_forearm_forward_angular_velocity |
| Forward Kinematic Sequence | N/A | Sequence of peak forward angular velocities. Optimal sequence is ‘torso-upper_arm-forearm’ | forward_kinematic_sequence |
| Forward Trunk Arm Speedup | N/A | Speedup factor of peak forward angular velocities from the torso to the upper arm. | forward_trunk_arm_speedup |
| Forward Upper Arm Forearm Speedup | N/A | Speedup factor of peak forward angular velocities from the upper arm to the forearm. | forward_upper_arm_forearm_speedup |
| 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 |
| 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 |
Twist Kinematic Sequence Metrics
| Metric | Units | Description | Column Name |
|---|---|---|---|
| Peak Pelvis Twist Angular Velocity | degrees/second | Peak twist angular velocity of the pelvis segment in the serve direction | pelvis_peak_twist_angular_velocity |
| Peak Torso Twist Angular Velocity | degrees/second | Peak twist angular velocity of the torso segment in the serve direction | trunk_peak_twist_angular_velocity |
| Peak Upper Arm Twist Angular Velocity | degrees/second | Peak twist angular velocity of the upper arm segment in the serve direction | arm_peak_twist_angular_velocity |
| Twist Kinematic Sequence | N/A | Sequence of peak twist angular velocities. Optimal sequence is ‘torso-upper_arm-forearm’ | twist_kinematic_sequence |
| Twist Trunk Arm Speedup | N/A | Speedup factor of peak twist angular velocities from the torso to the upper arm. | twist_trunk_arm_speedup |
| Twist Pelvis Torso Speedup | N/A | Speedup factor of peak twist angular velocities from the pelvis to the trunk. | twist_pelvis_trunk_speedup |
Loading Phase Metrics
| Metric | Units | Description | Column Name |
|---|---|---|---|
| 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_front_knee_flexion |
| Loading Phase Max Knee Flexion Back Leg | degrees | Maximum amount of back leg knee flexion during the loading phase of the serve | loading_phase_max_back_knee_flexion |
| Loading Phase Trunk Tilt | degrees | Maximum amount of trunk side-side tilt towards the rear during the loading phase of the serve | loading_phase_trunk_tilt |
| Loading Phase Pelvis Tilt | degrees | Maximum amount of pelvis side-side tilt towards the rear during the loading phase of the serve | loading_phase_pelvis_tilt |
| Loading Phase Shoulder Hip Separation | degrees | Maximum difference in rotation of the shoulders and hips during the loading phase of the serve | loading_phase_shoulder_hip_separation |
| Loading Phase Ball Release Angle | degrees | Transverse plane arm angle at the instance of ball release | loading_phase_ball_toss_angle |
| Trunk Coil | deg | Maximum amount of trunk twist rotation away from the serve direction, like preloading the twist before the serve. | trunk_coil |
| Pelvis Coil | deg | Maximum amount of pelvis twist rotation away from the serve direction, like preloading the twist before the serve. | pelvis_coil |
Cocking and Acceleration Phase Metrics
| Metric | Units | Description | Column Name |
|---|---|---|---|
| Cocking Phase Max Shoulder External Rotation | degrees | Maximum amount of shoulder external rotation during the cocking phase of the serve | cocking_phase_max_shoulder_external_rotation |
| Cocking Phase Shoulder Hyperangulation | degrees | Maximum amount of shoulder horizontal abduction during the cocking phase of the serve | cocking_phase_shoulder_hyperangulation |
| 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_front_knee_extension_velocity |
| 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 | acceleration_phase_max_back_knee_extension_velocity |
| Acceleration Phase Max Elbow Extension Velocity | degrees/second | Maximum extension velocity of the dominant elbow during the acceleration phase of the serve | max_elbow_extension_velocity |
Contact Phase Metrics
| Metric | Units | Description | Column Name |
|---|---|---|---|
| Contact Phase Elbow Flexion | degrees | Amount of elbow flexion at apex | contact_phase_elbow_flexion |
| Contact Phase Shoulder Abduction | degrees | Amount of shoulder abduction at apex | contact_phase_shoulder_abduction |
| Contact Phase X Factor | degrees | Angle between the shoulders to hips in the transverse plane (twisting) at apex | contact_phase_x_factor |
| Contact Phase Trunk Tilt | degrees | Degrees of side-side trunk tilt at apex | contact_phase_trunk_tilt |
| Trunk Stretch | deg | Twist range of motion of the trunk. | trunk_stretch |
| Pelvis Stretch | deg | Twist range of motion of the pelvis. | pelvis_stretch |
Notes
- Kinematic data typically captured at 240Hz for Tennis Overhand Serve