Documentation Index
Fetch the complete documentation index at: https://docs.uplift.ai/llms.txt
Use this file to discover all available pages before exploring further.
Break down the precise timing and sequencing of movements from the pelvis, trunk, and arms, to identify inefficiencies in swing mechanics, improve consistency, and maximize energy transfer from the lower body through the core to the bat.
Uplift offers dozens of events and metrics to track baseball hitting for little league to professional athletes.
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 Baseball Hitting
- All boolean variables (true/false = 1/0) return -1 if metric unable to be calculated.
