Dimensions
Required Inputs for processing:- handedness: the handedness of the batter [‘left’, ‘right’]
Variables
Output variables from hitting analysis.Events
Identify specific time points during the hit.| Event | Short Description | Column Name |
|---|---|---|
| Initiation | Lead foot begins to move prior to max knee raise. | initiation_frame |
| Max Foot Raise | Maximum height of the lead foot. | max_foot_raise_frame |
| Foot Contact | Front foot contacts the ground. | foot_contact_frame |
| Pelvis Velocity Initiation (Launch) | Start of pelvis rotation (launch event). | pelvis_initiation_frame |
| Max X Factor | Maximum hip-shoulder separation before the twisting motion. | max_x_factor_frame |
| X Factor Zero Crossing | Shoulder-hip separation crosses zero after Max X Factor. | x_factor_zero_crossing_frame |
| Wrist Initiation | Start of wrist movement during the swing. | wrist_movement_initiation_frame |
| Twist | Average timing of peak pelvis, trunk, and arm angular velocities. | twist_frame |
| Peak Pelvis Ang Vel | Instant of pelvis peak angular velocity. | peak_pelvis_velocity_frame |
| Peak Trunk Ang Vel | Instant of trunk peak angular velocity. | peak_trunk_velocity_frame |
| Peak Arm Ang Vel | Instant of lead arm peak angular velocity. | peak_arm_velocity_frame |
| Peak Wrist Angular Velocity | Instant of maximum wrist angular velocity. | peak_wrist_angular_velocity_frame |
| Ball Contact | Estimated timing of ball contact (audio signal primary, swing through secondary). | ball_contact_frame |
| Swing Through | Rear wrist passes in front of the lead wrist — batter commits to swing. | swing_through_frame |
| Pelvis Velocity Termination | First local minimum after peak pelvis velocity. | pelvis_velocity_termination_frame |
| End Twist | End of twisting motion — X Factor velocity returns to 0 deg/s. | end_twist_frame |
Movement Flags
Find inefficiencies during the hitting motion.| Metric | Units | Short Description | Column Name |
|---|---|---|---|
| Leads With Wrist | boolean | Wrist initiation occurs before pelvis initiation. | leads_with_wrist |
| Sway | boolean | Pelvis drifts backward more than 8 cm (~3 in) around max knee raise. | sway |
| Sway Leg | boolean | Rear knee passes behind the ankle (away from pitcher). | sway_leg |
| Knee Dominant | boolean | Rear hip and ankle angles differ >25° at launch with <15° ankle dorsiflexion. | knee_dominant_swing |
| Vertical Pelvis Hike | boolean | Pelvis finishes higher at ball contact than at launch. | vertical_pelvis_hike |
| Lateral Pelvis Tilt | boolean | Pelvis tilts upward more than 10 deg during the swing. | excessive_lateral_pelvis_tilt |
| Drifting Forward | boolean | Pelvis drifts forward more than 15 cm (~6 in) from launch to ball contact. | drifting_forward |
Kinematic Sequence
Order and magnitude of pelvis, trunk, and upper arm peak rotational velocity (deg/s) during the swing.| Metric | Units | Short Description | Column Name |
|---|---|---|---|
| Kinematic Sequence | N/A | Order of peak segment angular velocities. Correct sequence is pelvis-trunk-arm. | kinematic_sequence_order |
| Peak Pelvis Angular Velocity | deg/s | Max rotational speed of the pelvis. | peak_pelvis_angular_velocity |
| Peak Trunk Angular Velocity | deg/s | Max rotational speed of the trunk. | peak_trunk_angular_velocity |
| Peak Arm Angular Velocity | deg/s | Max rotational speed of the lead upper arm. | peak_arm_angular_velocity |
| Trunk to Arm Speed Up | ratio | Speed increase ratio from trunk to arm. | trunk_to_arm_velocity_speedup |
| Pelvis to Trunk Speed Up | ratio | Speed increase ratio from pelvis to trunk. | pelvis_to_trunk_velocity_speedup |
Timing & General Metrics
Durations, sequencing info, and general session metadata.| Metric | Units | Short Description | Column Name |
|---|---|---|---|
| Time to Ball Contact | s | Duration from initiation to ball contact. | time_to_ball_contact |
| Time to Launch | s | Duration from initiation to launch (pelvis velocity initiation). | time_to_launch |
| Pelvis Acceleration Time | s | Time from pelvis rotation start to peak pelvis angular velocity. | pelvis_acceleration_time |
| Pelvis Deceleration Time | s | Time from peak pelvis angular velocity to end of rotation. | pelvis_decceleration_time |
| Handedness | N/A | Batter handedness [‘right’ or ‘left’]. | handedness |
| Ball Contact Method | N/A | Detection method: both audio, single audio, or swing through. | ball_contact_method |
Lower Body & Stride
Lower body positions, stride mechanics, and forward movement during the swing.| Metric | Units | Short Description | Column Name |
|---|---|---|---|
| Stride Length | in | Lead ankle at foot contact to rear ankle at max foot raise. | stride_length |
| Hip Hinge | deg | Max rear hip flexion between max foot raise and foot contact. | hip_hinge |
| Lead Knee Angle at Ball Contact | deg | Lead knee flexion at ball contact. | lead_knee_angle_at_ball_contact |
| Drifting Forward Magnitude | in | Pelvis forward drift from launch to ball contact — see Drifting Forward flag. | drifting_forward_magnitude |
Trunk & X-Factor
Trunk and pelvis rotation angles, coil, and swing plane metrics.| Metric | Units | Short Description | Column Name |
|---|---|---|---|
| Max X Factor | deg | Max hip-shoulder separation angle. | max_x_factor |
| Trunk Coil | deg | Max trunk rotation away from the pitcher (0 = facing pitcher). | trunk_coil |
| Trunk Tilt at Launch | deg | Side-to-side trunk tilt at launch (+ = towards pitcher). | trunk_tilt_at_launch |
| Shoulder Rotation Plane Flexion | deg | Trunk flexion to align with the average shoulder rotation plane. | shoulder_rotation_plane_flexion |
| Shoulder Rotation Plane Tilt | deg | Trunk tilt to align with the average shoulder rotation plane (+ = towards pitcher). | shoulder_rotation_plane_tilt |
Arm, Hand & Connection
Upper extremity angles, distances, and hand positions relative to the body.| Metric | Units | Short Description | Column Name |
|---|---|---|---|
| Scap Load at Launch | deg | Rear shoulder flexion (+) or extension (-) at launch. | rear_scap_load_at_launch |
| Elbow Flexion at Launch | deg | Rear elbow flexion at launch. | rear_elbow_flexion_at_launch |
| Elbow Flexion at Ball Contact | deg | Rear elbow flexion at ball contact. | rear_elbow_flexion_at_ball_contact |
| Rear Arm Connection | in | Avg distance from rear elbow to mid-torso between launch and ball contact. | rear_arm_connection |
| Inter Elbow Distance at Elbow Slot | m | Elbow-to-elbow distance at elbow slot. | inter_elbow_distance_at_elbow_slot |
| Inter Elbow Distance at Trunk Peak | m | Elbow-to-elbow distance at peak trunk angular velocity. | inter_elbow_distance_at_trunk_peak |
| Inter Elbow Distance at Ball Contact | m | Elbow-to-elbow distance at ball contact. | inter_elbow_distance_at_ball_contact |
| Relative Hand Position - Towards Pitcher | in | Wrist position relative to mid-shoulders along pitcher axis at foot contact. | relative_hand_position_towards_pitcher |
| Relative Hand Position - Up | in | Wrist height relative to mid-shoulders at foot contact. | relative_hand_position_up |
| Relative Hand Position - Away from Body | in | Wrist distance away from mid-shoulders (lateral) at foot contact. | relative_hand_position_away_from_body |
| Linear Stretch | in | Lead ankle to wrist center distance along pitch direction at foot contact. | linear_stretch |
Time Series Metrics
Metrics describing motion over the duration of the capture, changing values with every frame. Use in combination with the keypoints and kinematics from Generic Outputs.| Metric | Units | Short Description | Column Name |
|---|---|---|---|
| Trunk Center of Mass Position X | m | Trunk COM X position. | trunk_center_of_mass_x |
| Trunk Center of Mass Position Y | m | Trunk COM Y position (vertical). | trunk_center_of_mass_y |
| Trunk Center of Mass Position Z | m | Trunk COM Z position. | trunk_center_of_mass_z |
| Body Center of Mass Position X | m | Whole-body COM X position. | whole_body_center_of_mass_x |
| Body Center of Mass Position Y | m | Whole-body COM Y position (vertical). | whole_body_center_of_mass_y |
| Body Center of Mass Position Z | m | Whole-body COM Z position. | whole_body_center_of_mass_z |
| Trunk Global Flexion | deg | Trunk sagittal plane flexion relative to global frame. | trunk_global_flexion |
| Trunk Global Tilt | deg | Trunk frontal plane tilt relative to global frame. | trunk_global_tilt |
| Trunk Global Rotation | deg | Trunk transverse plane rotation relative to global frame. | trunk_global_rotation |
| Pelvis Global Tilt | deg | Pelvis frontal plane tilt relative to global frame. | pelvis_global_tilt |
| Pelvis Global Rotation | deg | Pelvis transverse plane rotation relative to global frame. | pelvis_global_rotation |
Bat Metrics
Descriptors of bat positions, speeds, and more during the swing.| Metric | Units | Short Description | Column Name |
|---|---|---|---|
| Attack Angle | deg | Bat path angle relative to horizontal at contact. | attack_angle |
| On Plane Efficiency | % | % of swing path within 10 deg of optimal plane (foot contact to ball contact). | on_plane_efficiency |
| Launch Position | deg | Bat angle relative to spine in the sagittal plane at launch. | launch_position |
| Sweet Spot Fore Aft Position At Contact | m | Fore/aft position of bat sweet spot relative to pelvis at contact. | sweet_spot_fore_aft_position_at_contact |
| Attack Direction | deg | Horizontal bat angle relative to home plate (indicates hit direction). | attack_direction |
| Swing Path | deg | Vertical bat path angle in the 0.04 s leading up to ball contact. | swing_path_angle |
Notes
- Kinematic data typically captured at 240Hz for Softball Hitting
- All boolean variables (true/false = 1/0) return -1 if metric unable to be calculated.