Reboot Motion Definitions

Last revision: 2023-04-17

What is Momentum?

Momentum is a holistic physics concept that describes the amount of mass and velocity an object contains at any given time. The definition of momentum is simply mass X velocity. Specifically, we focus on analyzing angular momentum around the athlete’s center of mass, which is similarly defined as inertia X angular velocity. There are three aspects of momentum that make it an ideal concept to focus on when analyzing athletic movement:

Momentum accounts for size. By multiplying velocity and mass together, we can precisely compare two body parts, or two people.
For example, when comparing the velocity of a pitcher’s hand to the velocity of their torso, the hand will always be higher just because it’s smaller. However, what we are concerned with is understanding the athlete’s movement technique and how it impacts performance, not the difference in size across body parts.
Another example is comparing the body part velocities of a much larger player to a much smaller player. The much larger player will almost always have lower velocities than the smaller player, just due to the fact that they have more mass. However, they could be generating much more momentum, also due to the greater amount of mass, which is the thing that matters for maximizing pitch speed and bat speed.
Therefore, when we account for size by analyzing momentum instead of velocity, we better understand how well an athlete actually transferred momentum from one body part to the next, or how the momentum-generating capacity compares across athletes of different sizes.
Momentum has direction, allowing us to analyze if two body parts are well aligned in their direction, such that they can more efficiently transfer velocity through the body.
Momentum is conserved. This means that we can analyze how efficiently velocity flows from the ground through the body. We can better understand how, where, and why velocity is lost or gained in an athletic movement. The only way to get more momentum into the body is to push harder on the ground and generate higher ground reaction forces.

Analysis Themes

Sequence

In an athletic movement, the athlete pushes on the ground, and the ground pushes back, adding momentum to the athlete’s body. To efficiently flow through the body, momentum should reach a peak in each body part in a specific sequence from the ground to the pitching hand or bat (or the body part of interest). This section of the analysis depicts the athlete’s sequence of momentum peaks, and looks at how closely they match the desired sequence.

Rotation Planes

As the athlete accelerates each body part, the body part rotates in a plane. We calculate the tilt of this plane by looking at the direction of the momentum. It is most efficient for these planes to be aligned in space, such that the momentum from one body part directly adds to the next body part in the sequence. In this section, we analyze how well each body part’s rotation plane aligns with the desired body part to maximize (i.e. the pitching hand or bat).

Momentum

This section analyzes the amount of momentum generated by each body part at its peak. This is specifically calculated in the direction of the body part that the athlete is trying to maximize (i.e. the pitching hand or the bat) via a vector projection.

Balance

In addition to generating momentum in the desired direction (i.e. towards home plate for a pitcher or out towards the field for a hitter) an athlete generates momentum in a side to side plane. Momentum generated in this plane can manifest as a loss of balance, as it causes an athlete to tip to one side or the other (i.e. towards the 1st or 3rd base side of the field). For each body part, this section depicts where the peak momentum towards each side of the field occurs over the course of the delivery. It is numerically shown as the percent of momentum towards that side. For example, a 70% number in the direction of 3rd base means that, at that point in time, 70% of that body part’s momentum was causing the athlete to tip towards 3rd base.

The axis of rotation for this side to side momentum is the y-axis, which is the axis pointed along the desired direction of motion, for example the direction in which a pitcher is throwing or a batter is hitting towards the field. Using the right hand rule, positive side to side momentum is clockwise about this axis.

Ranges of Motion

In this section, we analyze both the full minimum and full maximum range of motion for each joint, as well as the max and min used within the most efficient sequence. We then calculate the percent of the total range of motion that was used within the sequence as the "range_norm", which stands for "range normalized to full range".

As each body part is rotating in an athlete’s movement, the more time and space an athlete creates between body part momentum peaks, the more room there is for the athlete to add momentum from one body part to the next. The way an athlete creates ‘space’ between body parts is by allowing the body parts to rotate through greater ranges of motion.

Keep in mind, it is most efficient for an athlete to use each joint range of motion at the appropriate time in the sequence. For example, the more ‘space’ an athlete can create between the lower half momentum peak and the torso momentum peak, the more momentum the athlete can theoretically add from the lower half to the torso. This space manifests itself as the thoracic spine rotation range of motion (this is more or less what some quantify as hip/shoulder separation). However, using the T-spine range of motion prior to the lower half peak is not as efficient, because it means that the torso is pushing back on the lower half as it is accelerating, thereby slowing down the lower half and reducing its momentum-generating potential.

The full min and full max are just straightforward calculations of the min and max range of motions reached within the delivery or swing in its entirety. However, the min and max within the kinematic sequence, are the min and max joint range used before the next body part in the desired kinematic sequence reaches its momentum peak. So for example, with the rear hip internal rotation, we want that range of motion to be used before the torso reaches its momentum peak. Therefore, we calculate the min and max of this joint range before the time point at which the torso peaks. From this, we calculate the "range_norm" as the (max - min) / (full_max - full_min), as it is the range within the sequence, normalized to the full range observed within the movement as a whole.

These are the typical joints in a report, as well as the interval when the "range_norm" is calculated:

rear_hip_ir: prior to the torso momentum peak
lead_knee_flex: between foot plant and ball release for pitching, or before the torso momentum peak for hitting
lumbar_ext: after the rear leg momentum peak for pitching
spine_rot: after the rear leg momentum peak for pitching, between the lower half and lead arm for hitting
pitch_shoulder_horz: after the torso momentum peak and prior to ball release
pitch_elbow_flex: after the upper arm momentum peak and prior to ball release

Coordinate Systems

For a pitcher in the global coordinate system, Y points from the pitching rubber along the ground towards home plate. X points from the pitching rubber towards third base along the ground, and Z points up to the sky from the pitching rubber.

For a hitter, Y instead points from the plate out towards the pitching rubber, and X points from the right-handed batters’ box to the left-handed batters’ box.

Metrics

Available in the action_by_action.csv in the report-data folder or in folders labeled as metrics. If v1 is in the folder name, the metrics were calculated using data from Pipeline v1, or if v2 is in the folder name, data came from Pipeline v2.

Available body segments - rear_leg, lead_leg, lower_half, torso, lead_arm, bat, pitch_up_arm, pitch_forearm, pitch_hand, total
Available body joints - rear_hip_ir, lead_knee_flex, lumbar_ext, spine_rot, pitch_shoulder_horz (i.e. arm_flex defined above), pitch_elbow_flex
lower_half<or any body segment>_proj_norm_time - norm time (as described below) at which the body part reaches its momentum peak
lower_half<or any body segment>_start_norm_time - the norm time at which the body part begins to increase (i.e. increases past 5% of its full max)
rear_hip_ir<or any body joint>_range_norm - the percent of the joint’s range of motion used within the most efficient sequence
rear_hip_ir<or any body joint>_range_full_max - the full maximum range of motion seen within the delivery as a whole
rear_hip_ir<or any body joint>_range_max - the maximum range of motion seen within the most efficient sequence
rear_hip_ir<or any body joint>_range_max_norm_time - the normalized time point at which the joint reaches its max range within the sequence
rear_hip_ir<or any body joint>_range_full_min - the full minimum range of motion seen within the delivery as a whole
rear_hip_ir<or any body joint>_range_min - the minimum range of motion seen within the most efficient sequence
rear_hip_ir<or any body joint>_range_min_norm_time - the normalized time point at which the joint reaches its min range within the sequence
lower_half<or any body segment>_side_max - the maximum momentum value clockwise about the desired direction of motion
lower_half<or any body segment>_side_max_percent - the percent of the total momentum in that body part that is clockwise about the desired direction of motion when the clockwise momentum is at its maximum
lower_half<or any body segment>_side_max_norm_time - the norm time at which the body part reaches its side to side momentum maximum in the clockwise direction
lower_half<or any body segment>_side_min - the minimum momentum value clockwise about the desired direction of motion, or in other words the maximum momentum in the counterclockwise direction
lower_half<or any body segment>_side_min_percent - the percent of the total momentum in that body part that is counterclockwise about the desired direction of motion at the time when the counterclockwise momentum is at its maximum (clockwise momentum is at a minimum)
lower_half<or any body segment>_side_min_norm_time - the norm time at which the body part reaches its maximum counterclockwise momentum (clockwise momentum is at a minimum)
lower_half<or any body segment>_proj_max - the peak momentum in the direction of the desired body part (i.e. the pitching hand or the bat), called ‘proj’ because it is calculated as a vector projection of the total momentum in the desired plane
lower_half<or any body segment>_vert_ang - the tilt of the rotational momentum plane relative to horizontal
org_movement_id - your organizations movement ID
reboot_movement_id - Reboot Motion’s internal movement ID
date - the date on which the movement occurred
number - the movement number in the session, based on the order session metadata file

Processed Data

Available in CSVs in the processed-data folder - if the folder name contains v2, the data came from Pipeline v2, otherwise it came from Pipeline v1.

time - time from start of data recording
norm_time - normalized time, with 0 being approximately foot plant and 100 being ball release for a pitcher (defined as the time of peak pitching hand momentum), and then for a hitter, 0 is the first time the momentum towards the field starts to increase, and 100 is the time of peak momentum in the body
player - player ID
movement_num - chronological movement number in the outing as defined by the meta data file
movement_id - the organization’s movement ID
Total_energy – the total rotational and linear kinetic energy in the body
Total_Angular_Momentum_(X, Y, Z, Mag, Proj) – the total angular momentum in the body in the x, y, and z directions. X represents north-south momentum (i.e. over-the-top / ferris wheel momentum, where negative X momentum creates velocity towards home plate for a pitcher). Y represents side to side momentum (towards third base is positive for a pitcher, towards the first base dugout is positive for a hitter). Z represents east-west (side-arm / merry-go-round) momentum, with positive Z momentum creating velocity towards home plate for right handed pitchers / towards the field for right handed hitters, and negative Z momentum creating velocity towards home plate for left handed pitchers / towards the field for left handed hitters. Mag represents the magnitude of the momentum. Proj represents the component of the momentum in the direction of the pitching hand at its peak for a pitcher, or the component of the momentum in the direction of the lead arm at its peak for a hitter (the reason we don’t use the bat here is the bat is not present in all data sets).
LLeg_energy – the total rotational and kinetic energy in the left leg
LLeg_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the left leg
RLeg_energy – the total rotational and linear kinetic energy in the right leg
RLeg_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the right leg
Legs_energy – the total rotational and linear kinetic energy in the legs
Legs_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the legs
RPV_energy – the total rotational and linear kinetic energy in the pelvis
RPV_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the pelvis
LowerHalf_energy – the total rotational and linear kinetic energy in the legs and pelvis
LowerHalf_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the legs and pelvis
Torso_energy – the total rotational and linear kinetic energy in the trunk
Torso_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the trunk
RHE_energy – the total rotational and linear kinetic energy in the head
RHE_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the head
LArm_energy – the total rotational and linear kinetic energy in the left arm
LArm_Angular_Momentum_(X, Y, Z, Mag, Proj) - the angular momentum in the left arm
LAR_energy – the total rotational and linear kinetic energy in the left upper arm
LAR_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the left upper arm
LFA_energy – the total rotational and linear kinetic energy in the left forearm
LFA_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the left forearm
LHA_energy – the total rotational and linear kinetic energy in the left hand
LHA_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the left hand
RArm_energy – the total rotational and linear kinetic energy in the right arm
RArm_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the right arm
RAR_energy – the total rotational and linear kinetic energy in the right upper arm
RAR_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the right upper arm
RFA_energy – the total rotational and linear kinetic energy in the right forearm
RFA_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the right forearm
RHA_energy – the total rotational and linear kinetic energy in the right hand
RHA_Angular_Momentum_(X, Y, Z, Mag, Proj) – the angular momentum in the right hand
hand_r_(X, Y, Z) - the x, y, and z position of the right hand
hand_l_(X, Y, Z) - the x, y, and z position of the left hand
center_of_mass_(X, Y, Z) - the x, y, and z position of the center of mass
calcn_r_(X, Y, Z) - the x, y, and z position of the right calcaneus
calcn_l_(X, Y, Z) - the x, y, and z position of the left calcaneus
hand_r_(Xv, Yv, Zv) - the x, y, and z velocity of the right hand
hand_l_(Xv, Yv, Zv) - the x, y, and z velocity of the left hand

Inverse Kinematics

Available in CSVs in the inverse-kinematics folder, created via Reboot Motion’s inverse kinematics process, using a movement-specific, scaled, skeletal model. Joint angle will be fixed at 0 degrees if enough info to calculate it is not available in the motion capture data. Calculated via Pipeline v2.

time - the time relative to the start of the trial
time_from_max_hand - the time relative to the time of maximum dominant hand velocity
event - entries denote specific frames when events happened; the first entry in this column is typically a time stamp to enable aligning the raw source data; other event options include 1) ball_release_hawkeye (time of ball release provided by Hawk-Eye), 2) bat_contact_hawkeye (time of bat contact if contact occurred), 3) bat_nearest_hawkeye (time when the bat was nearest the ball if no contact occurred), 4) max_stride (approximate time of foot contact, when stride length is at its peak and lead foot has moved downward), 5) max_dom_hand_velo (time of maximum dominant hand velocity in the y-direction)
org_movement_id - the ID submitted along with the play (e.g. the mlb play ID or an ID generated from the KinaTrax file name)
movement_id - the Reboot Motion unique ID for this movement - note that this file is often generated before an ID is assigned, so it may ofent be n/a. The org_movement_id should always be assigned and can be used to retrieve the movement_id
pelvis_rot - the global rotation of the pelvis (as defined by a horizontal line between the hip joint centers) about the z axis - augmented by handedness, such that zero for a right handed has the player facing along the positive x axis with positive rotation counterclockwise about the z axis, and zero for a left handed player has the player facing along the negative x axis with positive rotation clockwise about the z axis
pelvis_side - the tilt of the pelvis (as defined by the line between the hip joint centers) relative to a horizontal line passing through the hip joint centers - augmented by handedness, such that a positive rotation would cause a player to lean towards their dominant hand side
torso_rot - torso rotation around the spine relative to the pelvis - augmented by handedness, such that a positive rotation would cause the player to face towards the field of play
torso_side - torso lateral bending, augmented by handedness, such that a positive rotation would cause a player to lean towards their dominant hand side
torso_ext - torso extension at the lower back, such that a positive rotation is towards the player’s posterior
right(left)_hip_flex - hip flexion (positive) and extension (negative)
right(left)_hip_add - hip adduction (positive) and abduction (negative)
right(left)_hip_rot - hip rotation around the long axis (positive towards the center of the body)
right(left)_knee - knee flexion angle with zero as full extension
right(left)_ankle_inv - ankle inversion (positive) and eversion (negative)
right(left)_ankle_flex - ankle flexion (positive) and extension (negative)
right(left)_sternoclavicular_elev - clavicle rotation relative to the sternum, such that positive rotation causes a shoulder "shrug"
right(left)_elbow - elbow flexion with zero as full extension
right(left)_forearm_pro - forearm pronation, such that zero is fully supinated and pronation is positive
right(left)_wrist_dev - wrist deviation, with ulnar deviation as positive
right(left)_wrist_flex - wrist flexion, with rotation towards the palm as positive
<joint angle>_vel - the derivative vs time of the joint angle in units of degrees / s
<joint angle>_acc - the second derivative vs time of the joint angle in units of degrees / s^s

Shoulder Descriptions

Note: we have two shoulder descriptions available: 1) shoulder abduction and horizontal flexion, or 2) shoulder plane of elevation and elevation, which is well described here.

Shoulder Description 1)

right(left)_shoulder_abd - upper arm abduction (positive) away from the body’s center and adduction (negative)
right(left)_shoulder_flex - forward (positive) and backward (negative) horizontal flexion

Shoulder Description 2)

right(left)_shoulder_plane - the plane of elevation along which the upper arm moves from a non-elevated to an elevated position, measured using an angle similar to lines of longitude on a globe, such that planes towards the front of the body are more positive
right(left)_shoulder_elev - the angle of elevation of the upper arm in the previously specified plane of elevation, measured using an angle similar to lines of latitude on a globe, such that more elevated upper arm positions are more positive

In Both Shoulder Descriptions

right(left)_shoulder_rot - upper arm arm internal (positive) and external (negative) rotation

Body Part Key Points

Available in the inverse kinematics CSVs. These are low-pass-filtered, time series of the body part key points from the raw Motion Capture data.

Notes:

Columns will be null if not available in the motion capture data.
For Hawk-Eye data, the below position columns have had the y coordinate re-centered such that y = 0 = the average y coordinate of the ankle joint centers at t = 0. This was done to remove variability caused by forward / backward shifts in the player's initial position or by noise in the motion capture calibration.

Columns:

R(L)FOOT_(X, Y, Z) - the x, y, z location of a location at the end of the foot on the middle toe
R(L)BTOE_(X, Y, Z) - the x, y, z location of the big (first) toe
R(L)STOE_(X, Y, Z) - the x, y, z location of the small (fifth) toe
R(L)HEEL_(X, Y, Z) - the x, y, z location of the heel of the foot
R(L)AJC_(X, Y, Z) - the x, y, z location in space of the ankle joint center
R(L)MMAL_(X, Y, Z) - the x, y, z location in space of the ankle medial malleolus
R(L)LMAL_(X, Y, Z) - the x, y, z location in space of the ankle lateral malleolus
R(L)KJC_(X, Y, Z) - the x, y, z location in space of the knee joint center
R(L)MFC_(X, Y, Z) - the x, y, z location in space of the medial femoral condyle
R(L)LFC_(X, Y, Z) - the x, y, z location in space of the lateral femoral condyle
R(L)HJC_(X, Y, Z) - the x, y, z location in space of the hip joint center
MIDHIP_(X, Y, Z) - the x, y, z location between the hip joint centers provided by the motion capture data source
R(L)PINKY_(X, Y, Z) - the x, y, z location of the pinky (fifth) finger
R(L)THUMB_(X, Y, Z) - the x, y, z location of the thumb (first finger)
R(L)HAND_(X, Y, Z) - the x, y, z location in space of the index finger
R(L)WJC_(X, Y, Z) - the x, y, z location in space of the wrist joint center
R(L)FAulna_(X, Y, Z) - the x, y, z location in space of the ulnar landmark on the wrist
R(L)FAradius_(X, Y, Z) - the x, y, z location in space of the radial landmark on the wrist
R(L)EJC_(X, Y, Z) - the x, y, z location in space of the elbow joint center
R(L)MEL_(X, Y, Z) - the x, y, z location in space of the medial epicondyle of the humerus
R(L)LEL_(X, Y, Z) - the x, y, z location in space of the lateral epicondyle of the humerus
R(L)SJC_(X, Y, Z) - the x, y, z location in space of the shoulder joint center
CENP_(X, Y, Z) - the x, y, z calculated location in space of the midpoint between the hip joint centers
CENSH_(X, Y, Z) - the x, y, z calculated location in space of the midpoint between the shoulder joint centers
NECK_(X, Y, Z) - the x, y, z location in space of the base of the neck
Skullbase_(X, Y, Z) - the x, y, z location in space of the base of the skull
LEYE_(X, Y, Z) - the x, y, z location of the left eye
REYE_(X, Y, Z) - the x, y, z location of the right eye
Skull_(X, Y, Z) - the x, y, z location of the skull, often calculated as the mid point between the ears
BHANDLE_(X, Y, Z) - the x, y, z location of the bat handle
BHEAD_(X, Y, Z) - the x, y, z location of the bat head
Baseball_(X, Y, Z) - the x, y, z location of the baseball

IK at Time Points

Available in the ik-at-time-points folder, these are data from inverse kinematics, taken at specific key time points in the player's movement. The suffix (_ms, _mer, _mhv) indicates the time point.

Max Stride (_ms) - Approximately foot contact; defined as the moment when the player's lead leg reaches it's max stride length while also being below a vertical threshold, indicated the foot is likely touching the ground
Max External Shoulder Rotation (_mer) - the moment when the rear / pitching shoulder reaches max external shoulder rotation
Max Dominant Hand Velocity (_mhv) - the moment when the dominant hand reaches max velocity in the desired direction of travel

Momentum and Energy

Available in the momentum-energy folder, these are time series of body segment momentum and energy.

Notes:

Player weight information is necessary for these calculations.
Mass distribution and inertial parameters are specified according to Leva, P. de. “Adjustments to Zatsiorsky-Seluyanov's segment inertia parameters.” Journal of Biomechanics 29 (1996): 1223-1230.
If other mass distribution or inertial parameters are desired, this is possible, please let us know.
Body segment abbreviations are mostly taken from standards put out by C-Motion, Inc for Visual3D
The suffix "Mag" stands for the magnitude of the angular momentum
The suffix "Proj" stands for the scalar projection of the angular momentum in the direction of the desired body part to maximize at it's peak - i.e. the hand for pitching or the bat for hitting

Columns:

RHE_(Local, Remote)_AngMom_(X, Y, Z) - for the head, the local angular momentum around the body-centered coordinate axes (presented in the global coordinate system), and the remote angular momentum around the total body center of mass
LAR_(Local, Remote)_AngMom_(X, Y, Z) - for the left upper arm, the local and remote angular momentum
LFA_(Local, Remote)_AngMom_(X, Y, Z) - for the left forearm, the local and remote angular momentum
LHA_(Local, Remote)_AngMom_(X, Y, Z) - for the left hand, the local and remote angular momentum
RAR_(Local, Remote)_AngMom_(X, Y, Z) - for the right upper arm, the local and remote angular momentum
RFA_(Local, Remote)_AngMom_(X, Y, Z) - for the right forearm, the local and remote angular momentum
RHA_(Local, Remote)_AngMom_(X, Y, Z) - for the right hand, the local and remote angular momentum
Torso_(Local, Remote)_AngMom_(X, Y, Z) - for the torso, the local and remote angular momentum
LowerTorso_(Local, Remote)_AngMom_(X, Y, Z) - for the lower part of the torso, as defined by de Leva in the paper above, which is approximately the pelvis, the local and remote angular momentum
RTH_(Local, Remote)_AngMom_(X, Y, Z) - for the right thigh, the local and remote angular momentum
RSK_(Local, Remote)_AngMom_(X, Y, Z) - for the right shank (the lower part of the leg), the local and remote angular momentum
RFT_(Local, Remote)_AngMom_(X, Y, Z) - for the right foot, the local and remote angular momentum
LTH_(Local, Remote)_AngMom_(X, Y, Z) - for the left thigh, the local and remote angular momentum
LSK_(Local, Remote)_AngMom_(X, Y, Z) - for the left shank, the local and remote angular momentum
LFT_(Local, Remote)_AngMom_(X, Y, Z) - for the left foot, the local and remote angular momentum
Bat_(Local, Remote)_AngMom_(X, Y, Z) - for the bat, the local and remote angular momentum
RHE_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the head, the local + remote angular momentum around the total body's center of mass
LAR_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the left upper arm, the local + remote angular momentum around the total body's center of mass
LFA_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the left forearm, the local + remote angular momentum around the total body's center of mass
LHA_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the left hand, the local + remote angular momentum around the total body's center of mass
RAR_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the right upper arm, the local + remote angular momentum around the total body's center of mass
RFA_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the right forearm, the local + remote angular momentum around the total body's center of mass
RHA_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the right hand, the local + remote angular momentum around the total body's center of mass
Torso_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the torso, the local + remote angular momentum around the total body's center of mass
LowerTorso_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the lower part of the torso, the local + remote angular momentum around the total body's center of mass
RTH_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the right thigh, the local + remote angular momentum around the total body's center of mass
RSK_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the right shank (the lower part of the leg), the local + remote angular momentum around the total body's center of mass
RFT_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the right foot, the local + remote angular momentum around the total body's center of mass
LTH_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the left thigh, the local + remote angular momentum around the total body's center of mass
LSK_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the left shank, the local + remote angular momentum around the total body's center of mass
LFT_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the left foot, the local + remote angular momentum around the total body's center of mass
Bat_Angular_Momentum_(X, Y, Z, Mag, Proj) - for the bat, the local + remote angular momentum around the total body's center of mass
LArm_Angular_Momentum_(X, Y, Z, Mag, Proj) - for all the segments of the left arm, the local + remote angular momentum around the total body's center of mass
RArm_Angular_Momentum_(X, Y, Z, Mag, Proj) - for all the segments of the right arm, the local + remote angular momentum around the total body's center of mass
Arms_Angular_Momentum_(X, Y, Z, Mag, Proj) - for all the segments of both arms, the local + remote angular momentum around the total body's center of mass
LLeg_Angular_Momentum_(X, Y, Z, Mag, Proj) - for all the segments of the left leg, the local + remote angular momentum around the total body's center of mass
RLeg_Angular_Momentum_(X, Y, Z, Mag, Proj) - for all the segments of the right leg, the local + remote angular momentum around the total body's center of mass
Legs_Angular_Momentum_(X, Y, Z, Mag, Proj) - for all the segments of both legs, the local + remote angular momentum around the total body's center of mass
LowerHalf_Angular_Momentum_(X, Y, Z, Mag, Proj) - for both legs + the lower torso, the local + remote angular momentum around the total body's center of mass
Total_Angular_Momentum_(X, Y, Z, Mag, Proj) - for all the segments in the entire body, the local + remote angular momentum around the total body's center of mass
RHE_Linear_Momentum_(X, Y, Z) - for the head, the linear momentum in the global coordinate system
LAR_Linear_Momentum_(X, Y, Z) - for the left upper arm, the linear momentum in the global coordinate system
LFA_Linear_Momentum_(X, Y, Z) - for the left forearm, the linear momentum in the global coordinate system
LHA_Linear_Momentum_(X, Y, Z) - for the left hand, the linear momentum in the global coordinate system
RAR_Linear_Momentum_(X, Y, Z) - for the right upper arm, the linear momentum in the global coordinate system
RFA_Linear_Momentum_(X, Y, Z) - for the right forearm, the linear momentum in the global coordinate system
RHA_Linear_Momentum_(X, Y, Z) - for the right hand, the linear momentum in the global coordinate system
Torso_Linear_Momentum_(X, Y, Z) - for the torso, the linear momentum in the global coordinate system
LowerTorso_Linear_Momentum_(X, Y, Z) - for the lower part of the torso, the linear momentum in the global coordinate system
RTH_Linear_Momentum_(X, Y, Z) - for the right thigh, the linear momentum in the global coordinate system
RSK_Linear_Momentum_(X, Y, Z) - for the right shank (the lower part of the leg), the linear momentum in the global coordinate system
RFT_Linear_Momentum_(X, Y, Z) - for the right foot, the linear momentum in the global coordinate system
LTH_Linear_Momentum_(X, Y, Z) - for the left thigh, the linear momentum in the global coordinate system
LSK_Linear_Momentum_(X, Y, Z) - for the left shank, the linear momentum in the global coordinate system
LFT_Linear_Momentum_(X, Y, Z) - for the left foot, the linear momentum in the global coordinate system
Bat_Linear_Momentum_(X, Y, Z) - for the bat, the linear momentum in the global coordinate system
RHE_(Trans, Rot, Kinetic)_Energy - for the head, translational / rotational / total kinetic energy
LAR_(Trans, Rot, Kinetic)_Energy - for the left upper arm, translational / rotational / total kinetic energy
LFA_(Trans, Rot, Kinetic)_Energy - for the left forearm, translational / rotational / total kinetic energy
LHA_(Trans, Rot, Kinetic)_Energy - for the left hand, translational / rotational / total kinetic energy
RAR_(Trans, Rot, Kinetic)_Energy - for the right upper arm, translational / rotational / total kinetic energy
RFA_(Trans, Rot, Kinetic)_Energy - for the right forearm, translational / rotational / total kinetic energy
RHA_(Trans, Rot, Kinetic)_Energy - for the right hand, translational / rotational / total kinetic energy
Torso_(Trans, Rot, Kinetic)_Energy - for the torso, translational / rotational / total kinetic energy
LowerTorso_(Trans, Rot, Kinetic)_Energy - for the lower part of the torso, translational / rotational / total kinetic energy
RTH_(Trans, Rot, Kinetic)_Energy - for the right thigh, translational / rotational / total kinetic energy
RSK_(Trans, Rot, Kinetic)_Energy - for the right shank (the lower part of the leg), translational / rotational / total kinetic energy
RFT_(Trans, Rot, Kinetic)_Energy - for the right foot, translational / rotational / total kinetic energy
LTH_(Trans, Rot, Kinetic)_Energy - for the left thigh, translational / rotational / total kinetic energy
LSK_(Trans, Rot, Kinetic)_Energy - for the left shank, translational / rotational / total kinetic energy
LFT_(Trans, Rot, Kinetic)_Energy - for the left foot, translational / rotational / total kinetic energy
Bat_(Trans, Rot, Kinetic)_Energy - for the bat, translational / rotational / total kinetic energy
R(L)HA_(X, Y, Z) - the global position of the center of mass of the hand segment
R(L)FT_(X, Y, Z) - the global position of the center of mass of the foot segment
Center_of_Mass_(X, Y, Z) - the global position of the total body center of mass
norm_time - normalized time, where 0 = the time of max stride and 100 = the time of max dominant hand velocity - meant to indicate the general beginning and end of a movement, for synchronizing time series data across trials
rel_frame - relative frame, the frame count relative to the frame of max dominant hand velocity, which is defined to be 0
dom_hand_letter - dominant hand letter, either "r" or "l", the abbreviation of right or left indicating the dominant hand for this movement
mass_total - the total mass of the player used in these momentum and energy calculations