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. 2023 Mar-Apr;15(2):274-281.
doi: 10.1177/19417381221078537. Epub 2022 Apr 23.

The Clinician's Guide to Baseball Pitching Biomechanics

Alek Z Diffendaffer  1 , Michael S Bagwell  2 , Glenn S Fleisig  1 , Yuki Yanagita  1 , Megan Stewart  1 , E Lyle Cain Jr  1 , Jeffrey R Dugas  1 , Kevin E Wilk  1   2
Affiliations

The Clinician's Guide to Baseball Pitching Biomechanics

Alek Z Diffendaffer et al. Sports Health. 2023 Mar-Apr.

Abstract

Context: Improper baseball pitching biomechanics are associated with increased stresses on the throwing elbow and shoulder as well as an increased risk of injury.

Evidence acquisition: Previous studies quantifying pitching kinematics and kinetics were reviewed.

Study design: Clinical review.

Level of evidence: Level 5.

Results: At the instant of lead foot contact, the elbow should be flexed approximately 90° with the shoulder at about 90° abduction, 20° horizontal abduction, and 45° external rotation. The stride length should be about 85% of the pitcher's height with the lead foot in a slightly closed position. The pelvis should be rotated slightly open toward home plate with the upper torso in line with the pitching direction. Improper shoulder external rotation at foot contact is associated with increased elbow and shoulder torques and forces and may be corrected by changing the stride length and/or arm path. From foot contact to maximum shoulder external rotation to ball release, the pitcher should demonstrate a kinematic chain of lead knee extension, pelvis rotation, upper trunk rotation, elbow extension, and shoulder internal rotation. The lead knee should be flexed about 45° at foot contact and 30° at ball release. Corrective strategies for insufficient knee extension may involve technical issues (stride length, lead foot position, lead foot orientation) and/or strength and conditioning of the lower body. Improper pelvis and upper trunk rotation often indicate the need for core strength and flexibility. Maximum shoulder external rotation should be about 170°. Insufficient external rotation leads to low shoulder internal rotation velocity and low ball velocity. Deviation from 90° abduction decreases the ability to achieve maximum external rotation, increases elbow torque, and decreases the dynamic stability in the glenohumeral joint.

Conclusion: Improved pitching biomechanics can increase performance and reduce risk of injury.

Sort: Level C.

Keywords: flaws, elbow; shoulder; throwing.

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Conflict of interest statement

The following authors declared potential conflicts of interest: G.S.F. is a paid consultant for Major League Baseball and Dari Motion. E.L.C. is a paid consultant for Arthrex, Smith & Nephew, Biomet, and Theralase; has received lecture payments from Arthrex, Smith & Nephew, and Biomet; and received patent support and royalty payments from Arthrex. J.R.D. is a paid consultant for Arthrex and Theralase; has received lecture payments, patent support, and royalties from Arthrex; and has stock options with Theralase and Topical Gear. K.E.W. is a paid medical advisory board member for AlterG Treadmill, IntelliSkin USA, LiteCure Laser Co, and Hyperice; is a paid consultant for Theralase and WebExercises; has received educational grants from Bauerfeiend Braces, ERMI, and Performance Health; and has received royalty payments from CV Mosby, Elsevier, Human Kinetics, and Slack publishers.

Figures

Figure 1.
Figure 1.
Side view representative time points of the phases of pitching: windup from (a) first motion to (b) maximum knee height, stride from (b) maximum knee height to (c) foot contact, arm cocking from (c) foot contact to (d) maximum shoulder external rotation, arm acceleration from (d) maximum shoulder external rotation to (e) ball release and arm deceleration and follow-through from (e) ball release to (f) follow-through.
Figure 2.
Figure 2.
Front view representative time points of the phases of pitching: windup from (a) first motion to (b) maximum knee height, stride from (b) maximum knee height to foot contact (C), arm cocking from (c) foot contact to (d) maximum shoulder external rotation, arm acceleration from (d) maximum shoulder external rotation to (e) ball release and arm deceleration and follow-through from (e) ball release to (f) follow-through.
Figure 3.
Figure 3.
Lead foot mechanics at the instant of lead foot contact include stride length, lead foot position, and angle. Stride length is reported as the percentage of the pitcher’s height and is measured as the distance from the back ankle at maximum knee to the lead ankle at the instant of foot contact (A). Lead foot position is defined as the distance between the back ankle’s position at maximum knee height and the lead ankle’s position at the instant of foot contact (B). Lead foot angle is defined as the angle created between a line from the midankle to the toe and a line from the midankle toward home plate (C).
Figure 4.
Figure 4.
Lead knee flexion is measured as the angle created between the thigh and shank segments. Lead knee flexion is measured at the instant of foot contact (left) and ball release (right).
Figure 5.
Figure 5.
Shoulder abduction is measured as the angle between the upper arm and trunk in the frontal plane. Shoulder abduction is measured at the instant of foot contact and ball release.
Figure 6.
Figure 6.
Shoulder external rotation is defined as the rotation of the upper arm segment about its long axis. Shoulder external rotation is first measured at the instant of foot contact for proper arm position and timing.
Figure 7.
Figure 7.
Maximum shoulder external rotation occurs at the end of the arm-cocking phase as the arm rapidly transitions to arm acceleration with internal rotation.
Figure 8.
Figure 8.
Recommended exercises to enhance neuromuscular control of the thoracic and lumbar spine: (a) kneeling thoracic mobility and (b) quadruped thread the needle.
See this image and copyright information in PMC

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