Pitching Biomechanics and Shoulder Function in Baseball Pitchers with
                    Scapular Dyskinesis

Tsun-Shun Huang; Yi-Hsuan Weng; Che-Chia Chang; Yung-Shen Tsai; Jiu-jenq Lin

doi:10.1055/a-1939-7229

International Journal of Sports Medicine, Table of Contents

Int J Sports Med 2023; 44(05): 369-375
DOI: 10.1055/a-1939-7229

Orthopedics & Biomechanics

Pitching Biomechanics and Shoulder Function in Baseball Pitchers with Scapular Dyskinesis

Tsun-Shun Huang

¹Department of Physical Therapy and Assistive Technology, National Yang Ming Chiao Tung University, Taipei, Taiwan

,

Yi-Hsuan Weng

²School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan

,

Che-Chia Chang

³Graduate Institute of Sports Sciences, University of Taipei, Taipei, Taiwan

,

Yung-Shen Tsai

⁴Graduate Institute of Sports Equipment Technology, University of Taipei, Taipei, Taiwan

,

Jiu-jenq Lin

²School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan

› Author Affiliations

Abstract

The primary purpose was to investigate the influence of scapular dyskinesis (SD) on pitching biomechanics and shoulder function in high school baseball pitchers. The secondary purpose was to identify possible factors associated with shoulder function in pitchers with SD. Thirty-eight pitchers were classified into the SD group (n=26) or the non-SD group (n=12). They were evaluated with the Kerlan-Jobe Orthopaedic Clinic shoulder and elbow (KJOC) scale and clinical measurements of shoulder characteristics, and with measurements of scapular kinematics, muscle activation, and ball speed during fastball pitching. Compared to the controls, the pitchers with SD had less scapular external rotation (difference=11.3 degrees, ES=0.92, p=0.012) during overall pitching and less upper trapezius (UT) activation during the late cocking (difference=7.1%, ES=0.79, p=0.019) and acceleration phases (difference=12.5%, ES=0.75, p=0.035). Higher UT activation during the late cocking phase was significantly associated with higher KJOC scores (standardized β=0.415, p=0.039). In conclusion, deficits in scapular external rotation and decreased UT activation during pitching were found in pitchers with SD. Higher UT activation may be important for shoulder function in pitchers with SD.

Key words

kinematics - muscle activation - regression - performance

Full Text

References

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