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An individualized linear model approach for estimating scapular kinematics during baseball pitching
1School of Behavioral Sciences and Education, Pennsylvania State University Harrisburg, 777 W. Harrisburg Pike, Middletown, PA 17057, USA.
Journal of Biomechanics
|December 14, 2020
Summary
A new individualized linear model accurately estimates scapular orientation during pitching motions. This method improves upon the acromion marker cluster (AMC), offering better insights into shoulder function for injury prevention and performance enhancement.
Area of Science:
- Biomechanics
- Sports Medicine
- Orthopedics
Background:
- Accurate measurement of dynamic scapular orientation is crucial for assessing shoulder function in baseball pitching.
- Current methods like the acromion marker cluster (AMC) have limitations in capturing scapular movement during pitching.
- Individualized linear models offer a potential improvement for estimating scapular orientation.
Purpose of the Study:
- To evaluate a pitching-specific individualized linear model for estimating scapular orientation in static positions.
- To compare the accuracy of the linear model against palpation and the acromion marker cluster (AMC).
Main Methods:
- Developed individualized linear models for 14 collegiate pitchers based on humerothoracic and scapulothoracic orientations.
- Collected static arm posture data throughout individual throwing motions.
- Compared linear model and AMC estimates against palpation at intermediate test positions.
Main Results:
- Linear model estimates closely matched palpation results across all scapulothoracic axes.
- The acromion marker cluster (AMC) showed significant differences in estimating rotation and tilt during cocking and follow-through.
- Linear models demonstrated smaller root mean square error (RMSE) values (2.8-6.3°) compared to AMC (5.1-15.8°).
Conclusions:
- The individualized linear model accurately estimates static scapular orientation during pitching motions.
- This approach offers superior accuracy compared to the acromion marker cluster (AMC).
- Future dynamic applications could enhance understanding of shoulder function, injury risk, rehabilitation, and performance in pitchers.
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