Differences Among Overhand, 3-Quarter, and Sidearm Pitching Biomechanics in Professional Baseball Players
in Journal of Applied BiomechanicsClick name to view affiliation
Results Physical Therapy and Training Center
Andrews Research and Education Foundation
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The purpose of this study was to assess biomechanical differences among overhand, 3-quarter, and sidearm arm slot professional baseball pitchers. It was hypothesized that kinematic and kinetic differences would be found among the 3 groups, with sidearm pitchers demonstrating greater movement along the transverse plane and overhead pitchers demonstrating greater movement along the sagittal plane. Based upon arm slot angle at ball release, 30 overhand, 156 three-quarter, and 21 sidearm pitchers were tested using a 240-Hz motion analysis system, and 37 kinematic and kinetic parameters were calculated. One-way analyses of variance (α = .01) was employed to assess differences among groups. The comparisons showed the sidearm group had less shoulder anterior force, whereas the overhand group had the least elbow flexion torque. At ball release, trunk contralateral tilt and shoulder abduction were greatest for the overhand group and least for sidearm group. Additionally, the sidearm group demonstrated the lowest peak knee height, most closed foot angle, greatest pelvis angular velocity, and shoulder external rotation. The overhand group had the greatest elbow flexion at foot contact and greatest trunk forward tilt at ball release. The greater elbow flexion torque and shoulder external rotation exhibited by sidearm pitchers may increase their risk of labral injury. Conversely, the lower shoulder anterior force in sidearm pitchers may indicate lower stress on shoulder joint capsule and rotator cuff.
Escamilla is with the Department of Physical Therapy, California State University, Sacramento, CA, USA; Results Physical Therapy and Training Center, Sacramento, CA, USA; and Andrews Research and Education Foundation, Gulf Breeze, FL, USA. Slowik, Diffendaffer, and Fleisig are with the American Sports Medicine Institute, Birmingham, AL, USA.
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