The Clinician’s Guide to Baseball Pitching Biomechanics

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.

Feasibility of the pitch efficiency rating: A novel tool for systematic assessment of pitching mechanics in developing throwing athletes

“…Other authors have suggested that pitchers may demonstrate suboptimal mechanics not only because of motor-learning and pattern development but also because physical factors such as range of motion, strength, and stability across the kinetic chain may limit an athlete's ability to achieve ideal positions. 6,7,9,10 Creating a systematic process for 2D-motion analysis of the pitching motion can improve communication between medical professionals and those involved in athlete development (coaches, performance staff). In doing so the multidisciplinary team may address physical factors limiting pitching performance, design comprehensive rehabilitation plans, and monitor mechanical compensations during return-to-throwing programs.…”

“…3 Commonly, the motion is broken down into six phases, interconnected by a series of kinematic events, beginning with windup and ending with ball release (Figure 1). 2,[4][5][6][7][8] Limitations in strength, range of motion, and suboptimal mechanics can affect each phase of the throwing motion. Physical and mechanical deficits can therefore place increased stress across the shoulder and elbow leading to elevated injury risk.…”

“…Physical and mechanical deficits can therefore place increased stress across the shoulder and elbow leading to elevated injury risk. 6,7,9,10 In the scientific literature, biomechanical pitch efficiency refers to the relationship between ball velocity and normalized varus torque across the elbow. Studies using 3D-motion capture to investigate energy flow through the kinetic chain have also extended the concept of pitch efficiency to forces across the shoulder.…”

“…[12][13][14] Previous studies have correlated kinematic events during the throwing motion with kinetic forces across the shoulder and elbow. 7 Thus, kinematic analysis of key positions in the pitching motion through readily accessible two-dimensional (2D) technologies may provide insight into areas of mechanical inefficiency.…”

“… 2,4–8 Limitations in strength, range of motion, and suboptimal mechanics can affect each phase of the throwing motion. Physical and mechanical deficits can therefore place increased stress across the shoulder and elbow leading to elevated injury risk 6,7,9,10 . In the scientific literature, biomechanical pitch efficiency refers to the relationship between ball velocity and normalized varus torque across the elbow.…”