The influence of shoulder abduction and external rotation on throwing arm kinetics in professional baseball pitchers

Manzi, Joseph E.; Dowling, Brittany; Trauger, Nicolas; Fu, Michael C.; Hansen, Benjamin R; Dines, Joshua S.

doi:10.1177/17585732211010300

Cited by 11 publications

(9 citation statements)

References 33 publications

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“…In particular, professional and high school pitchers with increased forearm pronation at the individual level had decreased elbow flexion and shoulder external rotation at FC, while achieving maximum elbow extension velocity later in the pitch. These are important findings given that increased elbow flexion, 16 shoulder external rotation, 18 and improper timing of maximum segmental joint velocities 17 , 19 , 24 , 30 have all been studied previously and implicated in increased throwing arm kinetics or injury risk. Though these parameters were evaluated during later portions of the pitch (ie, maximum shoulder external rotation, ball release), the means by which one kinematic may influence subsequent portions of the pitching motion is important in elucidating combinatory sequences that may pose the highest injury risk to pitchers and warrants further investigation.…”

Section: Discussionmentioning

confidence: 72%

Forearm Pronation at Foot Contact: A Biomechanical Motion-Capture Analysis in High School and Professional Pitchers

Manzi

Dowling²,

Wang

et al. 2023

Orthopaedic Journal of Sports Medicine

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Background: It has previously been speculated that baseball pitchers who display excessive forearm pronation at foot contact (FC) have a higher propensity toward ulnar collateral ligament injury and subsequent surgery. Purpose: To evaluate the association between degree of forearm pronation/supination at FC and throwing arm kinetics in high school and professional pitchers, at both the individual (intrapitcher) and the group (interpitcher) level. Study Design: Descriptive laboratory study. Methods: High school (n = 41) and professional (n = 196) pitchers threw 8 to 12 fastballs while being assessed with a 3-dimensional motion-capture system (480 Hz). Pitchers at each playing level were divided into a supination or pronation subgroup depending on degree of forearm pronation at FC. Regression models were built to observe the relationship between forearm pronation at FC and kinetic and kinematic parameters of interest. Results: At both the individual and the group level of high school and professional pitchers, there was no significant correlation between forearm pronation at FC and elbow varus torque ( P min = .21). For every 10° increase in forearm pronation at FC in the individual high school pitcher, elbow flexion at FC decreased by 5°, whereas maximum elbow extension velocity was achieved 0.6% later in the pitch. In addition, elbow medial force increased by 4.1 N and elbow varus torque increased by 0.8 N·m for every 10° increase in forearm supination at FC. For every 10° increase in forearm supination in the individual professional pitcher, ball velocity increased by 0.5 m/s, shoulder external rotation at FC decreased by 11°, and elbow medial force decreased by 5.5 N. Conclusion: Supination- or pronation-predominant forearm motion during the pitch did not significantly differ between playing levels. Excessive forearm pronation at FC was not a significant risk factor for increased throwing arm kinetics for high school or professional pitchers. There was a weak positive association between forearm supination at FC and elbow varus torque in the individual high school pitcher. Ultimately, coaches and pitchers may be better served by redirecting their focus to other mechanical aspects of the pitch that may have stronger associations with injury risk implications as well as performance.

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Section: Discussionmentioning

confidence: 72%

Forearm Pronation at Foot Contact: A Biomechanical Motion-Capture Analysis in High School and Professional Pitchers

Manzi

Dowling²,

Wang

et al. 2023

Orthopaedic Journal of Sports Medicine

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“…In total, there were 1083 participants involved in this review across 33 studies, with 519 (48%) of them accounted for by eight baseball studies. The number of participants in each study ranged from 5 [41] to 322 [42]. Only two studies performed priori power analysis with shoulder internal/external range of motion as the primary outcome with significance level set at 0.05.…”

Section: Participants' Characteristicsmentioning

confidence: 99%

“…Thirty-five percent of the studies reviewed used inverse kinematics to obtain the force data at the joints of interest in order to investigate the indicators that lead to higher movement speed and performance [8,10,18,23,34,42,45,[49][50][51] and/or to examine the amount of forces incurred from the joints when executing the tasks from an injury risk perspective [23,41,42,45,59]. For example, [10] identified greater shoulder internal rotation moment as a strong predictor of higher racket head speed (r = 0.737); this was supported by [45] who found greater shoulder internal rotation moment in the skilled vs. novice players (p = 0.016).…”

Section: Type Of Biomechanical Analysis Approachesmentioning

confidence: 99%

“…Ref. [42] identified a positive association between shoulder abduction at ball release and shoulder distraction force, recommending that pitchers consider reducing shoulder abduction at the later stages of the pitching motion to approximately 80 • to minimize shoulder superior force, with no impact on ball velocity. Meanwhile, all reviewed studies utilized kinematic analysis to identify the technique differences that contribute to different movement speed and performance, with six studies comparing between genders [11,24,51,52,57,58], two compared between age groups [49,56], four comparing between sport-experience level [11,13,23,45,61], and three comparing between injured and non-injured athletes [9,43,60].…”

Section: Type Of Biomechanical Analysis Approachesmentioning

confidence: 99%

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A Systematic Review of the Biomechanical Studies on Shoulder Kinematics in Overhead Sporting Motions: Types of Analysis and Approaches

Ramasamy,

Usman,

Razman

et al. 2023

Applied Sciences

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The shoulder is a unique and complex joint in the human body with three bones and four joints, which makes it the most unstable joint in the body due to the amount of motion. To improve approaches toward understanding the performance of overhead throwing movements, this systematic review summarizes the type of analysis related to shoulder biomechanics involving overhead sporting motions. A search of seven databases identified 33 eligible studies, which were subsequently scored using the Modified Coleman Methodology Score scale. A total of nine articles from badminton, seven from baseball, five from volleyball, five from tennis, three from cricket, and one from softball were reviewed. All 33 studies evaluated shoulder kinematics and 12 of them also investigated the forces and torques (kinetics). The most common methods used were 3D motion analysis (76%), digital video cameras (15%), electromagnetic tracking system (6%), and finally 3% used IMU sensors. Overall, shoulder external rotation during the back swing, internal rotation, and elbow extension during the forward acceleration phase were the strongest predictors of high velocity overhead throwing movement. The findings provide some useful insights and guidance to researchers in their future contribution to the existing body of literature on shoulder overhead throwing movement biomechanics.

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“…7 Mechanics, such as increased horizontal abduction of the shoulder at foot contact (FC), increased maximum shoulder external rotation, and trunk lateral flexion at ball release (BR), have been related to both increased ball velocity 26,36,37,43 and increased risk of injury. 6,21,22,25,33,35,39 Arm path, or the total distance that the arm takes to get from the glove to BR, has become an increasingly discussed topic within the baseball community. 28 Arm path is a combination of wrist flexion/extension, forearm pronation/ supination, elbow flexion/extension, shoulder external/ internal rotation, and shoulder horizontal abduction/ adduction movements throughout the entire pitch.…”

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confidence: 99%

Relationship Between Arm Path, Ball Velocity, and Elbow Varus Torque in Professional Baseball Pitchers

Dowling,

Hodakowski,

Olmanson

et al. 2023

Orthopaedic Journal of Sports Medicine

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Background: Currently, most pitching instructors suggest a shorter arm path—the total distance the arm travels during pitching. Theoretically, this combination allows for better body segment sequencing, a more efficient energy transfer through the kinetic chain, and increased ball velocity, while limiting elbow varus torque. Hypothesis: Shorter arm paths would be associated with increased ball velocity and decreased elbow varus torque. Study Design: Descriptive laboratory study. Methods: A total of 182 professional pitchers threw 8 to 12 fastball pitches while evaluated by 3-dimensional motion capture (480 Hz). The arm path was calculated as the total distance the hand marker traveled during the pitch. The pitch was divided into early, late, and total arm paths. A linear regression model assessed the interpitcher relationship between arm path, elbow varus torque, and ball velocity. A linear mixed-effects model with random intercepts assessed intrapitcher relationships. Results: Interpitcher comparison showed that total arm path weakly correlated with greater elbow varus torque ( P = .025). Strong correlations were found between ball velocity and early ( R2 = 0.788; P < .001), late ( R2 = 0.787; P = .024), and total arm paths ( R2 = 0.792; P < .001). Strong positive intrapitcher correlations were found between elbow varus torque and early ( R2 = 0.962; P < .001) and total arm path ( R2 = 0.964; P < .001). For individual pitchers, there was a large variation in the early (30.1 ± 15.7 cm) and late (21.4 ± 12.1 cm) arm path. For every 30-cm (11.8-inch) increase in early arm path (the mean range for an individual pitcher), there was a 1.29-N (β = 0.0429) increase in elbow varus torque and a 0.354 m/s (0.79 mph) (β = 0.0118) increase in ball velocity. Conclusion: A shorter arm path correlated with decreased elbow varus torque and decreased ball velocity in intrapitcher comparisons. Determining the individual mechanics that decrease elbow varus torque may help coaches and trainers correct these patterns. Clinical Significance: A shorter arm path during the pitch can decrease elbow varus torque, which limits the load on the medial elbow but also has a detrimental effect on ball velocity. An improved understanding of the impact of shortening arm paths on stresses on the throwing arm may help minimize injury risk.

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The influence of shoulder abduction and external rotation on throwing arm kinetics in professional baseball pitchers

Cited by 11 publications

References 33 publications

Forearm Pronation at Foot Contact: A Biomechanical Motion-Capture Analysis in High School and Professional Pitchers

Forearm Pronation at Foot Contact: A Biomechanical Motion-Capture Analysis in High School and Professional Pitchers

A Systematic Review of the Biomechanical Studies on Shoulder Kinematics in Overhead Sporting Motions: Types of Analysis and Approaches

Relationship Between Arm Path, Ball Velocity, and Elbow Varus Torque in Professional Baseball Pitchers

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