The Motion Analysis Corp. batting analysis application measures the critical biomechanical parameters during left or right handed baseball or softball hitting swings. It supplies a complete kinematic report and comparison measures. The information can be used to compare the technique among batters and to changes over time. This guide will step though the procedures to operate BattingTrak and generate the computations and reports.
What you need
Motion Analysis Corp. Motion Capture system 3 to 35 Retroreflective Markers
|1||Top.Head||Topmost spot of the head|
|2||Front.Head||Front/center of the head|
|3||Rear.Head||Back/center of the head|
|4||R.Shoulder||End of the Clavicle (collar bone) – top of shoulder|
|5||R.Offset||Centered on the right clavicle|
|6||R.Elbow||Lateral epicondyle of the humerus|
|7||R.Wrist.Rad||Styloid Process of the Radius (Thumbside)|
|8||R.Wrist.Uln||Styloid Process of the Ulna|
|9||L.Shoulder||End of the Clavicle (collar bone) – top of shoulder|
|10||L.Elbow||Lateral epicondyle of the humerus|
|11||L.Wrist.Rad||Styloid Process of the Radius (Thumbside)|
|12||L.Wrist.Uln||Styloid Process of the ulna|
|13||C7||Top of the spine – base of the neck|
|14||R.ASIS||Over the right front of the hip|
|15||L.ASIS||Over the left front of the hip|
|16||V.Sacral||Over the base of the spine, L5-S1 joint|
|17||R.Thigh||About 1/3 the distance from hip joint to knee joint|
|18||R.Knee||On the Lateral Condyle|
|19||R.Shank||About 1/3 the distance from knee joint to ankle joint|
|20||R.Ankle||On the Lateral Malleolus (ankle bone)|
|21||R.Heel||Centered on the heel|
|22||R.Toe||Over the base of the second toe|
|23||L.Thigh||About 2/3 the distance from hip joint to knee joint|
|24||L.Knee||On the Lateral Condyle|
|25||L.Shank||About 2/3 the distance from knee joint to ankle joint|
|26||L.Ankle||On the Lateral Malleolus|
|27||L.Heel||Centered on the heel|
|28||L.Toe||Over the base of the second toe|
|29||Bat.End||Top of the Bat|
|30||Bat.Mid||Place on sweet spot of the bat|
|31||Bat.Handle||Above where the batter grips the bat|
|32||Bat.Knob||Bottom of Bat|
|33||Bat1||Place anywhere between Bat.Mid and Bat.Handle|
|34||Bat2||Place anywhere between Bat.Mid and Bat.Handle|
|35||Bat3||Place anywhere between Bat.Mid and Bat.Handle, non-colinear with Bat1 and Bat2|
Determining Your Markerset
BattingTrak can use a variety of markersets depending upon the desired calculations and how you want to display the player in the 3D pane. For example, if you are only interested in the bat motion, you just need to put markers on the bat (#29,30,31,32). BattingTrak will then provide the bat related data: bat speed, bat angle, loading angle, and bat speed and angle at contact. You also have the option to track one or more body segments: head, arms, hips, legs and feet. BattingTrak will then compute the segment related parameters. For example, if you use the three head markers (#1,2,3), the software will compute the Head Flexion/Extension, Head Tilt and Head Rotation angles. Of course, the more segments that you want to track, the more markers will be necessary. Although no specific markers are required for BattingTrak to make computations, you must ensure that the markers with the exact same names are in the markerset for the requisite computations to be made. If any additional markers are used (e.g. more asymmetry markers), BattingTrak will simply ignore them for its calculations.
There are several files specific to this Application that will be used by Cortex to help you set up, acquire and process your trials:
BattingTrak.mars – holds the marker and segment information.
BattingTrak.cal – holds the event information.
Two other files come with Cortex and are used by BattingTrak:
BattingTrak.graphs – holds the Cartesian graph information
BattingTrak.xls – holds the Excel graphing information (Ask us how it can show your logo and name.)
Data Collection Setup
Data collection for BattingTrak is similar as with any collection. There are some settings for calibration and data collection that you should use that will help ease the process. Learn about the recommended data collection settings in Data Collection Setup.
You should already be familiar with how to collect 3D data using Cortex. However, BattingTrak requires some specific collection procedures to ensure correct calculations. Trial Collection describes the recommended workflow to collect your trials.
Running the BattingTrak Solution
The BattingTrak software is simple to operate, and there are only a few fields to enter and several buttons to click. A video tutorial and instructions for operating the BattingTrak software is in Running the BattingTrak Solution.
The BattingTrak Report provides a series of biomechanical measures relevant to the batting motion. Here is a brief explanation of each of their meanings.
|1||X-Factor (deg)||Peak trunk rotation angle with respect to the pelvis (i.e., “hip-shoulder separation”)|
|2||Stance Width (in)||Distance between ankle joint centers in the anterior-posterior direction|
|3||Stance Length (in)||Distance between ankle joint centers in the medial-lateral direction|
|4||Bat Lag (deg)||Rotation angle of the bat about the superior-inferior axis of the trunk|
|5||Bat Speed (mph)||Linear speed of bat at ball impact|
|6||Bat Elevation (deg)||Bat angle (i.e., “take off angle”) with respect to the horizontal plane at ball impact|
Fortenbaugh, D. (2010). The Biomechanics of the Baseball Swing. Open Access Dissertations. Paper 540.
Milanovich, M, Nesbit, S (2014). A Three-Dimensional Kinematic and Kinetic Study of the College-Level Female Softball Swing. J Sports Sci Med, 13(1), 180-191.
Welch, C. M., Banks, S. A., Cook, F. F., & Draovitch, P. (1995). Hitting a baseball: A biomechanical description. Journal of Orthopaedic & Sports Physical Therapy, 22(5), 193-201.