Softball: Hitting

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 softball hitting for youth to professional athletes.

Example image of a woman doing a swing, side view

Dimensions

Required Inputs for processing:

handedness: the handedness of the batter [‘left’, ‘right’]

Variables

Output variables from hitting analysis.

Generic Outputs

Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See Generic Outputs for the full list.

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	Short Description	Column Name
Leads With Wrist	Wrist initiation occurs before pelvis initiation.	`leads_with_wrist`
Sway	Pelvis drifts backward more than 8 cm (~3 in) around max knee raise.	`sway`
Sway Leg	Rear knee passes behind the ankle (away from pitcher).	`sway_leg`
Knee Dominant	Rear hip and ankle angles differ >25° at launch with <15° ankle dorsiflexion.	`knee_dominant_swing`
Vertical Pelvis Hike	Pelvis finishes higher at ball contact than at launch.	`vertical_pelvis_hike`
Lateral Pelvis Tilt	Pelvis tilts upward more than 10 deg during the swing.	`excessive_lateral_pelvis_tilt`
Drifting Forward	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_deceleration_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.

Get Started

Resources

Biomechanics

Softball: Hitting

Dimensions

Variables

Generic Outputs

Events

Movement Flags

Kinematic Sequence

Timing & General Metrics

Lower Body & Stride

Trunk & X-Factor

Arm, Hand & Connection

Time Series Metrics

Bat Metrics

Notes

​Dimensions

​Variables

​Generic Outputs

​Events

​Movement Flags

​Kinematic Sequence

​Timing & General Metrics

​Lower Body & Stride

​Trunk & X-Factor

​Arm, Hand & Connection

​Time Series Metrics

​Bat Metrics

​Notes

Dimensions

Variables

Generic Outputs

Events

Movement Flags

Kinematic Sequence

Timing & General Metrics

Lower Body & Stride

Trunk & X-Factor

Arm, Hand & Connection

Time Series Metrics

Bat Metrics

Notes