Comparison of Kinematic Sequences During Curveball and Fastball Baseball Pitches

Performance of a sequential proximal-to-distal transfer of segmental angular velocity (or Kinematic Sequence) is reported to reduce stress on musculoskeletal structures and thus the probability of injury while also maximizing ball velocity. However, there is limited investigation regarding the Kinematic Sequence of the five body segments (Pelvis, Trunk, Arm, Forearm, and Hand) among baseball pitchers. Some biomechanical and epidemiology studies have reported an association of the curveball with increased risk for elbow injury among youth pitchers. Kinematic Sequences with altered distal upper extremity (forearm and hand) sequences have been associated with greater elbow valgus and shoulder external rotation torques compared to other Kinematic Sequences. Identifying Kinematic Sequence patterns during curveball pitches may lead to improved understanding of injury susceptibility. This study investigated the Kinematic Sequence patterns (and their variability) during curveball pitching and compared them to the sequences identified during fastball pitches. Using 3D motion analyses, 14 baseball pitchers (four high school, eight college, and two professional) performed 5–6 curveball pitches and 12 pitchers also threw fastball pitches in a simulated bullpen session. Eleven different curveball Kinematic Sequences were identified and 8 fastball Kinematic Sequences. There was no significant variability in the number of Kinematic Sequences performed between the two pitch types, (Z = −0.431, p = 0.67). The median number of KSs performed by each group was 2.5. The most frequently used Kinematic Sequences for both pitch types were due to alteration in the sequence of the distal segments. The total percentage of Kinematic Sequences with altered distal segment sequencing for the curveball pitches was 49% and 43% for fastball pitches. Identifying the frequency of Kinematic Sequences with altered timing of hand and forearm peak velocities across pitch types may lead to a better understanding of the stresses that individual pitchers incur.

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Role of Rotational Kinematics in Minimizing Elbow Varus Torques for Professional Versus High School Pitchers

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967118760780 ◽

2018 ◽

Vol 6 (3) ◽

pp. 232596711876078 ◽

Cited By ~ 8

Author(s):

Micheal J. Luera ◽

Brittany Dowling ◽

Mitchel A. Magrini ◽

Tyler W.D. Muddle ◽

Ryan J. Colquhoun ◽

...

Keyword(s):

High School ◽

External Rotation ◽

Ligament Injury ◽

Trunk Rotation ◽

Elbow Injury ◽

Risk Of Injury ◽

Increased Risk ◽

Rotational Kinematics ◽

Pelvis Rotation ◽

Baseball Pitchers

Background: Elbow injury rates among baseball pitchers are rapidly rising. However, this increase has been most dramatic among high school (HS) pitchers. Purpose: To examine pitch velocity and the kinetic and kinematic characteristics of HS versus professional (PRO) pitchers to identify potential differences that may play a role in the increased risk of ulnar collateral ligament injury in youth pitchers. Study Design: Controlled laboratory study. Methods: A total of 37 HS (mean ± SD: age, 16 ± 1 years) and 40 PRO (age, 21 ± 2 years) baseball pitchers completed maximal-effort baseball pitches during a single testing session, from which pitch velocity (PV), absolute and normalized elbow varus torque (EVTA and EVTN, respectively) during arm cocking and at maximum shoulder external rotation (MER), and 8 other elbow and shoulder torques or forces and rotational kinematics of the pelvis and trunk were analyzed, recorded, and compared. Results: PV was greater in PRO than HS athletes; EVTA was greater in PRO than HS athletes during arm cocking and at MER; but EVTN was similar during arm cocking and greater in HS than PRO athletes at MER. In PRO athletes, PV was not related to EVTA during arm cocking or MER ( r = 0.01-0.05). Furthermore, in PRO athletes, EVTA during arm cocking and at MER were inversely related to upper trunk rotation at hand separation and foot contact and to pelvis rotation at elbow extension ( r = –0.30 to –0.33). In contrast, in HS athletes, PV was strongly related to EVTA during arm cocking and MER ( r = 0.76-0.77). Furthermore, in HS athletes, PV and EVTA during arm cocking and at MER were moderately or strongly related to the other elbow and shoulder torques and forces ( r = 0.424-0.991), and EVTA was not related to upper trunk rotation or pelvis rotation throughout the throwing motion ( r = –0.16 to 0.15). Conclusion: The kinetic and rotational kinematic differences observed between PRO and HS pitchers in this study may help explain the greater performance of PRO pitchers while allowing them to minimize EVT during pitching. HS pitchers, however, do not appear to be as capable of utilizing the forces generated by rotation of their trunk and pelvis to aid in pitching, and those who throw the hardest generate the greatest forces at the shoulder and elbow. As a result, they experience higher EVTs relative to their body size, which may place them at an increased risk of injury. Clinical Relevance: HS pitchers throw harder primarily by generating larger forces in the arm and shoulder. Thus, owing to the relative physical immaturity of HS versus PRO pitchers, these factors may place them at an increased risk of injury. Coaches may first wish to focus on improving the rotational kinematics of HS pitchers rather than first focusing on achieving greater pitch velocities.

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What Can a Jump Tell Us About Elbow Injuries in Professional Baseball Pitchers?

The American Journal of Sports Medicine ◽

10.1177/0363546520905543 ◽

2020 ◽

Vol 48 (5) ◽

pp. 1220-1225

Author(s):

John Mayberry ◽

Scott Mullen ◽

Scott Murayama

Keyword(s):

Test Performance ◽

Injury Risk ◽

Reaction Force ◽

Professional Baseball ◽

Shoulder Injury ◽

Injury Rates ◽

Elbow Injury ◽

Increased Risk ◽

Elbow Injuries ◽

Baseball Pitchers

Background: The incidence rate of elbow injuries has been rising in recent years among professional baseball pitchers. Determining valid screening procedures that allow practitioners to identify pitchers at an increased risk of such injuries is therefore of critical importance. Purpose: To validate the use of countermovement jump (CMJ) tests as a diagnostic tool for pitcher conditioning. Study Design: Case-control study; Level of evidence, 3. Methods: More than 500 pitchers at a single professional baseball organization performed preseason CMJ assessments on a force plate before the 2013 to 2018 seasons. Three measurements were extracted from ground-reaction force data during the test: eccentric rate of force development (ERFD), average vertical concentric force (AVCF), and concentric vertical impulse (CVI). Athletic trainers at the organization collected detailed information on elbow and shoulder injury rates as well as workload (pitch count) throughout the rest of the season. Poisson regression models were fit to investigate the dependency of injury rates on CMJ test performance. Results: ERFD, CVI, and AVCF were all significant predictors of elbow injury risk after accounting for pitcher age, weight, and workload. The analysis identified 3 specific indicators of heightened risk based on the results of a CMJ scan: low ERFD, a combination of low AVCF and high CVI, and a combination of high AVCF and low CVI. In contrast, shoulder injury risk was roughly independent of all 3 CMJ test measurements. Conclusion: This study supports the hypothesis of the entire kinetic chain’s involvement in pitching by establishing a link between CMJ test performance and elbow injury risk in professional baseball pitchers. CMJ assessment may be a powerful addition to injury risk alert and prevention protocols. Pitchers in high-risk groups can be prescribed specific exercise plans to improve movement imbalances.

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Relationship between tightness of the hip joint and shoulder/elbow injury in high school baseball pitchers: a prospective study

Scientific Reports ◽

10.1038/s41598-020-76894-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Noritaka Hamano ◽

Hitoshi Shitara ◽

Tsuyoshi Tajika ◽

Tsuyoshi Ichinose ◽

Tsuyoshi Sasaki ◽

...

Keyword(s):

High School ◽

Risk Factor ◽

Lower Limb ◽

External Rotation ◽

Elbow Pain ◽

Elbow Injury ◽

Hip Range Of Motion ◽

Baseball Pitchers ◽

A Prospective Study ◽

The Relationship

AbstractSome studies have reported that upper limb tightness is a risk factor for shoulder/elbow pain in high school baseball pitchers; but there has been insufficient research on the relationship between lower limb tightness and shoulder and elbow pain in pitchers. This study aimed to clarify the correlation among pre-season hip range of motion (ROM) and shoulder and elbow disorders in high school baseball pitchers. We surveyed 125 high school pitchers. Hip ROM was measured in the supine and prone positions. After the season, based on their answers to the self-recorded questionnaire, a “shoulder or elbow injury” was defined as any condition resulting in the pitcher being considered disabled for ≥ 8 days. An independent t-test and logistic regression analysis were used for statistical analysis. Eleven disabled pitchers (9%) were identified during the season. In the injured group, the ROM of the plant side hip with 90° flexed external rotation was smaller than that in the non-injured group. Preseason limited ROM in the plant side hip with 90° flexed external rotation was a risk factor for the occurrence of shoulder/elbow pain in the season.

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Baseball Pitchers’ Kinematic Sequences and Their Relationship to Elbow and Shoulder Torque Production

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00429 ◽

2019 ◽

Vol 7 (7_suppl5) ◽

pp. 2325967119S0042

Author(s):

Donna Moxley Scarborough ◽

Shannon E. Linderman ◽

Javier E. Sanchez ◽

Eric M. Berkson

Keyword(s):

Upper Extremity ◽

External Rotation ◽

Kinetic Chain ◽

Joint Torques ◽

Ball Velocity ◽

Collegiate Baseball ◽

Angular Velocities ◽

Shoulder External Rotation ◽

Baseball Pitchers ◽

The Ideal

Objectives: Ball velocity is generated during the overhead baseball pitch via efficient force transmission up the kinetic chain, from the lower body up and outward to the throwing hand. The kinematic sequence, or the sequential timing pattern of peak angular velocities of body segments during a pitch, provides insight to segment position and motion control that drives the kinetic chain (Putnam CA, 1993). Previous publications report an ideal kinematic sequence (KS) where the timing of each body segment’s peak angular velocity occurs in a proximal-to-distal (PDS) pattern resulting in greater ball velocity and reduction in throwing arm injury risk (Fortenbaugh D, et.al, 2009). A recent study revealed that baseball pitchers perform a variety of KSs (Scarborough DM et.al, 2018). There is no known investigation of the relationship of kinematic sequences and throwing arm joint torques. The purpose of this study was to 1) identify the number of different KSs performed by each pitcher and 2) compare elbow valgus and shoulder external rotation (ER) and extension (Ext) torques between the 3 primary KSs performed during the fastball pitch. Methods: Fourteen collegiate baseball pitchers (20.57 ± 1.91 yr) underwent 3D biomechanical pitch analysis using 20 motion-capture Vicon MX™ cameras (360 Hz). A total of 119 fastball pitches with an average of 8.5 ± 2.71 pitches per player were analyzed. Elbow valgus and shoulder external rotation and extension torques were calculated. The timing of peak angular velocities for the pelvis, trunk, arm, forearm and hand body segments were recorded to generate each pitch’s KS. KSs were then divided into groups based on similarities to the ideal PDS pattern. ANCOVA statistical analyses were performed to compare joint torques across these KS groups with ball velocity as a covariate. Results: A total of 13 different KSs were observed across the 14 pitchers resulting in an average of 3 ± 1.41 different KSs per pitcher. Three different primary KS groups were identified: (1) PDS group: with a KS closest to the ideal PDS pattern (2) the Altered Distal Upper Extremity segment: with the forearm peaking after the hand (the most common group) and (3) Altered Proximal Upper Extremity segment order with the arm segment peaking after the hand (2nd most common). Across these three primary KS patterns, statistically significant differences were noted for elbow valgus torque [F(62,2) = 8.785, ɳ2 = .221, p < 0.00], shoulder external rotation (ER) torque [F(62,2) = 14.127, ɳ2 = .313, p < 0.00] and shoulder extension (Ext) torque [F(62,2) = 13.237, ɳ2 = .299, p < 0.00] (Figure 1). Conclusion: Our findings demonstrate that collegiate baseball pitchers performed an average of 3 different kinematic sequence patterns during fastball pitching. This is the first study to demonstrate a relationship between KSs and elbow and shoulder torque production. As anticipated, the PDS KSs produced the least torque across the elbow and shoulder joints. Alterations in Distal Upper Extremity KS was most common and generated the greatest shoulder Ext torques. Alterations in the Proximal Upper Extremity KS demonstrated the greatest elbow valgus and shoulder ER. Further study of the influence of kinematic sequence on joint torques in the baseball pitch may provide insight into pitching injuries and injury avoidance programs.

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Professional and Amateur Pitchers’ Perspective on the Ulnar Collateral Ligament Injury Risk

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119850777 ◽

2019 ◽

Vol 7 (6) ◽

pp. 232596711985077

Author(s):

Danica D. Vance ◽

Frank J. Alexander ◽

Brian W. Kunkle ◽

Mark Littlefield ◽

Christopher S. Ahmad

Keyword(s):

Injury Risk ◽

Ulnar Collateral Ligament ◽

Cross Sectional Study ◽

Ligament Injury ◽

Collateral Ligament ◽

Chi Square ◽

Cross Sectional ◽

Elbow Injury ◽

Increased Risk ◽

Baseball Pitchers

Background: Medial ulnar collateral ligament (UCL) injury is increasingly prevalent in professional baseball pitchers, and significant research has been devoted to understanding the risk factors and prevention strategies associated with it. To date, no study has investigated what the players themselves believe causes and prevents the injury. Purpose: To evaluate the opinions of UCL injuries among pitchers, including professional athletes. Study Design: Cross-sectional study. Methods: A total of 214 baseball pitchers (45 high school/college, 169 Major League Baseball [MLB]/Minor League Baseball) completed a 52-item questionnaire designed to evaluate their opinions on the cause of UCL injuries, injury prevention, and Tommy John surgery. Overall, 51 of the 214 pitchers had previously experienced a UCL injury. The frequency of the selection of each answer option was measured. Additionally, chi-square tests were used to compare (1) responses between professional and nonprofessional pitchers and (2) responses between pitchers with and without a previous UCL injury. Results: Only 45% of pitchers thought that UCL injuries are avoidable in MLB. Additionally, 55% of pitchers with a UCL injury had a history of elbow injuries as an adolescent/child, compared with 18% in the uninjured group ( P < .0001). Also, 72% of all surveyed pitchers agreed that fatigue over the course of a season increases the risk of UCL injuries, and the majority of pitchers agreed that inadequate rest from throwing both during the off-season (61%) and the season (59%) increases the risk of UCL injuries. Moreover, 59% of pitchers believed that a 6-man starting rotation would decrease the incidence of UCL injuries. Professional and nonprofessional pitchers significantly differed ( P = .005) in the type of pitch most prone to causing UCL injuries. Conclusion: Pitchers with a previous childhood elbow injury had a significantly higher incidence of UCL injuries during their adult career, suggesting possible predisposition to UCL injury and warranting further research. Fatigue and inadequate rest were of greatest concern among all pitchers for an increased risk of UCL injuries. Understanding and acknowledging the opinions that players have regarding UCL injuries are important to improve UCL education, prevention, and treatment.

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Correlation of Shoulder and Elbow Kinetics With Ball Velocity in Collegiate Baseball Pitchers

Journal of Athletic Training ◽

10.4085/1062-6040-50.1.06 ◽

2015 ◽

Vol 50 (6) ◽

pp. 629-633 ◽

Cited By ~ 17

Author(s):

Eric G. Post ◽

Kevin G. Laudner ◽

Todd A. McLoda ◽

Regan Wong ◽

Keith Meister

Keyword(s):

External Rotation ◽

Pearson Correlation ◽

Anatomical Landmarks ◽

Positive Correlation ◽

Weak Positive Correlation ◽

Ball Velocity ◽

Collegiate Baseball ◽

Shoulder External Rotation ◽

Baseball Pitchers ◽

Distraction Force

Context Throwing a baseball is a dynamic and violent act that places large magnitudes of stress on the shoulder and elbow. Specific injuries at the elbow and glenohumeral joints have been linked to several kinetic variables throughout the throwing motion. However, very little research has directly examined the relationship between these kinetic variables and ball velocity. Objective To examine the correlation of peak ball velocity with elbow-valgus torque, shoulder external-rotation torque, and shoulder-distraction force in a group of collegiate baseball pitchers. Design Cross-sectional study. Setting Motion-analysis laboratory. Patients or Other Participants Sixty-seven asymptomatic National Collegiate Athletic Association Division I baseball pitchers (age = 19.5 ± 1.2 years, height = 186.2 ± 5.7 cm, mass = 86.7 ± 7.0 kg; 48 right handed, 19 left handed). Main Outcome Measure(s) We measured peak ball velocity using a radar gun and shoulder and elbow kinetics of the throwing arm using 8 electronically synchronized, high-speed digital cameras. We placed 26 reflective markers on anatomical landmarks of each participant to track 3-dimensional coordinate data. The average data from the 3 highest-velocity fastballs thrown for strikes were used for data analysis. We calculated a Pearson correlation coefficient to determine the associations between ball velocity and peak elbow-valgus torque, shoulder-distraction force, and shoulder external-rotation torque (P < .05). Results A weak positive correlation was found between ball velocity and shoulder-distraction force (r = 0.257; 95% confidence interval [CI] = 0.02, 0.47; r2 = 0.066; P = .018). However, no significant correlations were noted between ball velocity and elbow-valgus torque (r = 0.199; 95% CI = −0.043, 0.419; r2 = 0.040; P = .053) or shoulder external-rotation torque (r = 0.097; 95% CI = −0.147, 0.329; r2 = 0.009; P = .217). Conclusions Although a weak positive correlation was present between ball velocity and shoulder-distraction force, no significant association was seen between ball velocity and elbow-valgus torque or shoulder external-rotation torque. Therefore, other factors, such as improper pitching mechanics, may contribute more to increases in joint kinetics than peak ball velocity.

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Biomechanical Differences Between Japanese and American Professional Baseball Pitchers

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119825625 ◽

2019 ◽

Vol 7 (2) ◽

pp. 232596711982562 ◽

Cited By ~ 2

Author(s):

Takanori Oi ◽

Shinichi Yoshiya ◽

Jon Slowik ◽

Alek Diffendaffer ◽

Yohei Takagi ◽

...

Keyword(s):

Knee Flexion ◽

The United States ◽

Abduction Angle ◽

Professional Baseball ◽

Shoulder Abduction ◽

Elbow Injury ◽

Risk Of Injury ◽

Ball Release ◽

Increased Risk ◽

Baseball Pitchers

Background: Although baseball injuries are common in both Japan and the United States, the majority of pitching injuries in Japanese players occur at the shoulder, whereas most pitching injuries in American players occur at the elbow. A biomechanical comparison between Japanese and American pitchers may help to identify the different injury mechanisms. Hypothesis: Japanese pitchers produce greater shoulder kinetics whereas American pitchers generate greater elbow kinetics. Also, kinematic differences will be found between the 2 groups, including longer stride and greater lead knee flexion for Japanese pitchers. Study Design: Descriptive laboratory study. Methods: Biomechanical data for 19 Japanese professional baseball pitchers and an age-matched group of 19 American professional baseball pitchers were collected by use of a 3-dimensional, automated, high-speed optical motion capture system. Anthropometric, kinetic, and kinematic data for both groups were compared by use of t tests ( P < .05). Results: American pitchers were taller and heavier and generated greater ball velocity (38.1 ± 1.6 vs 34.7 ± 1.1 m/s; P < .001) than their Japanese counterparts. Most elbow and shoulder kinetic parameters, including elbow varus torque (99 ± 17 vs 86 ± 17 N·m; P = .018), were greater for American pitchers. However, when normalized by bodyweight and height, shoulder horizontal adduction torque was greater for Japanese pitchers (6.8% ± 1.0% vs 5.8% ± 1.1%; P = .005). Japanese pitchers had longer stride (86% ± 5% vs 82% ± 6% of height; P = .023), greater shoulder abduction at ball release (101° ± 8° vs 94° ± 9°; P = .014), and greater knee flexion after ball release (39° ± 18° vs 28° ± 14°; P = .039). Japanese pitchers also demonstrated greater shoulder internal rotation velocity, elbow flexion, and elbow extension velocity. Conclusion: Greater elbow varus torque may predispose American pitchers to greater risk of elbow injury. Japanese pitchers may have increased risk of shoulder injury due to greater normalized horizontal adduction torque and greater abduction angle. Japanese pitchers may be able to reduce their shoulder torque and risk of injury by shortening their stride, reducing their lead knee flexion, and decreasing their throwing arm abduction. Clinical Relevance: Understanding anthropometric, kinetic, and kinematic differences between pitchers from the 2 countries may be of value to clinicians and coaches working to maximize performance of the pitchers while minimizing the risk of injury.

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Functional Hip Characteristics and Their Relationship With Ball Velocity in College Baseball Pitchers

Journal of Sport Rehabilitation ◽

10.1123/jsr.2018-0122 ◽

2019 ◽

Vol 28 (8) ◽

pp. 854-859

Author(s):

Osamu Yanagisawa ◽

Kenta Wakamatsu ◽

Hidenori Taniguchi

Keyword(s):

Muscle Strength ◽

Internal Rotation ◽

External Rotation ◽

Hip Muscle ◽

Flexion Extension ◽

Ball Velocity ◽

College Baseball ◽

Baseball Pitchers ◽

Hip Flexion ◽

Hip Extension

Context: Compared to shoulder and elbow functions, the hip functional characteristics of baseball pitchers have not been fully investigated. Therefore, little is known about the relationship between hip function and pitching performance. Objective: The purpose of this study was to evaluate the characteristics of hip flexibility and strength, focusing on their influences on the ball velocity in baseball pitchers. Design: Descriptive laboratory study. Setting: Laboratory and university baseball facility. Participants: Twenty-three college baseball pitchers. Interventions: Passive hip range of motion (ROM) and isometric hip muscle strength were bilaterally measured. The pitchers threw 20 fastballs at an official pitching distance. Main Outcome Measures: Bilateral hip ROM and strength in flexion, extension, abduction, adduction, and external and internal rotation; the maximal ball velocity. Results: The pivot side showed smaller hip external rotation ROM (P < .01), larger hip internal rotation ROM (P = .03), and greater hip adduction strength (P = .03) than the stride side. The hip extension ROM on the stride side had a negative correlation with the maximal ball velocity (r = −.58, P < .01). The maximal ball velocity (135.3 [4.1] km/h) positively correlated with the hip extension (r = .59, P < .01), flexion (r = .57, P < .01), abduction (r = .55, P < .01), and adduction (r = .55, P < .01) strength on the pivot leg, and the hip flexion (r = .53, P = .01), abduction (r = .67, P < .01), and adduction (r = .46, P = .03) strength on the stride leg. Conclusions: These findings suggest that baseball pitchers do not have marked side-to-side differences in hip flexibility and strength, and that an important fitness factor for increasing ball velocity is not the hip flexibility but the hip muscle strength of both legs.

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Preseason Neck Mobility Is Associated With Throwing-Related Shoulder and Elbow Injuries, Pain, and Disability in College Baseball Pitchers

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120920556 ◽

2020 ◽

Vol 8 (5) ◽

pp. 232596712092055

Author(s):

Laurie Lee Devaney ◽

Craig R. Denegar ◽

Charles A. Thigpen ◽

Adam S. Lepley ◽

Cory Edgar ◽

...

Keyword(s):

Range Of Motion ◽

Time Loss ◽

Elbow Injury ◽

Increased Risk ◽

Patient Reported ◽

Elbow Injuries ◽

College Baseball ◽

Baseball Pitchers ◽

Neck Mobility ◽

Injury Analysis

Background: Shoulder and elbow injuries in baseball pitchers, which can lead to significant pain and disability, have been on the rise at all levels of play for 3 decades. Despite anatomic and neurophysiological relationships, neck mobility has not been explored as a contributor to shoulder and elbow injuries in baseball pitchers. Hypothesis: Impaired neck mobility will increase the risk of shoulder and elbow injuries in college baseball pitchers. Study Design: Cohort study; Level of evidence, 2. Methods: Posture, neck mobility, and shoulder passive range of motion were measured in healthy college baseball pitchers during the 2018 preseason. Time loss (days lost because of shoulder or elbow injuries) and patient-reported disability via Functional Arm Scale for Throwers (FAST) scores were used to dichotomize pitchers into injured and uninjured groups. Receiver operating characteristic curves were generated, and accuracy values and risk ratios (RRs) were calculated to assess the diagnostic utility of the physical measures. Time-to-injury analysis was conducted to assess the timing of injuries. Results: A total of 49 pitchers (mean age, 19.92 ± 1.48 years; mean height, 187.04 ± 6.02 cm; mean weight, 89.14 ± 12.08 kg) completed the study. There were 10 pitchers (20.4%) who sustained a time-loss injury >7 days because of a shoulder or elbow injury. A Cervical Flexion-Rotation Test (CFRT) finding on the dominant side of ≤39° resulted in over 9 times the increased risk of time-loss injuries (RR, 9.38 [95% CI, 1.28-68.49]). Time-to-injury analysis demonstrated differences between the 2 groups (χ2 = 7.667; P = .01). Pitchers with a >39.25° finding on the CFRT played a mean 109.4 of 112 days (95% CI, 105-114) before the injury, while pitchers with ≤39.25° only played 83.6 of 112 days (95% CI, 68-99). A CFRT finding of ≤38° (RR, 3.91 [95% CI, 1.23-12.39]), cervical flexion range of motion of ≤64° (RR, 10.56 [95% CI, 1.50-74.34]), and weight of >86.9 kg (RR, 10.42 [95% CI, 1.14-213.70]) were also associated with an increased risk of patient-reported pain and disability on the FAST pitcher module. Conclusion: College baseball pitchers with less neck mobility during the preseason had an increased risk of time loss and shoulder and elbow disability during the season. The predictive value of these measures as part of a risk screening profile should be further explored.

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

Shoulder & Elbow ◽

10.1177/17585732211010300 ◽

2021 ◽

pp. 175857322110103

Author(s):

Joseph E Manzi ◽

Brittany Dowling ◽

Nicolas Trauger ◽

Michael C Fu ◽

Benjamin R Hansen ◽

...

Keyword(s):

Body Weight ◽

External Rotation ◽

Professional Baseball ◽

Shoulder Abduction ◽

3D Motion Analysis ◽

Ball Release ◽

Ball Velocity ◽

Shoulder External Rotation ◽

Baseball Pitchers ◽

Distraction Force

Background The relationships between shoulder abduction and external rotation with peak kinetic values at the shoulder and elbow in professional baseball pitchers are not well established. Methods Professional pitchers ( n = 322) threw 8–12 fastballs under 3D motion analysis (480 Hz). Pitchers were stratified into quartiles by shoulder abduction and external rotation at distinct timepoints. Regression analyses were performed to quantify associations between shoulder position and kinetics. Results Shoulder abduction remained relatively consistent throughout the pitch (foot contact–ball release: 85.5 ± 11.1–90.7 ± 8.4°); shoulder external rotation increased dramatically (foot contact–ball release: 30.8 ± 24.6–165.2 ± 9.7°). For every 10° increase in maximum shoulder rotation, shoulder superior force increased by 2.3% body weight ( p < 0.01), shoulder distraction force increased by 5.9% body weight ( p < 0.01), and ball velocity increased by 0.60 m/s ( p < 0.01). Shoulder abduction was significantly associated with shoulder superior force at all timepoints but not with ball velocity ( p > 0.05). For every 10° increase in shoulder abduction at ball release, shoulder superior force increased by 3.7% body weight ( p < 0.01) and shoulder distraction force increased by 11.7% body weight ( p < 0.01). Conclusion Increased shoulder abduction at ball release and increased maximum shoulder external rotation were associated with greater superior and distraction forces in the shoulder. Pitchers can consider decreasing shoulder abduction at later stages of the pitch to around 80° in order to minimize shoulder superior force, with no impact on ball velocity.

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