Estimation of Shoulder Behavior From the Viewpoint of Minimized Shoulder Joint Load Among Adolescent Baseball Pitchers

Abstract

Background:

During pitching, an overloaded joint reaction force exerted on the shoulder and excessive shoulder horizontal abduction at ball release are considered risk factors causing anterior shoulder pain for young baseball pitchers.

Hypothesis/Purpose:

The first aim was to examine the relationship between shoulder horizontal abduction position and force on the shoulder at ball release. The second was to identify the relative rotational position of the shoulder and the range of shoulder motion at ball release that minimize force on the shoulder. It was hypothesized that the amount of force on the shoulder would be exacerbated by excessive shoulder horizontal abduction.

Study Design:

Descriptive laboratory study.

Methods:

Participants were 183 adolescent baseball pitchers (mean ± SD age, 15.5 ± 1.2 years) without shoulder/elbow problems. Each pitcher threw 5 fastballs to a catcher behind a home plate. The kinematics and kinetics of the throwing shoulder during fastball pitching were calculated with 3-dimensional measurements from 36 reflective markers. In data analysis, the correlations were calculated between the relative rotational positions of the shoulder (abduction, horizontal adduction-abduction) and the forces on the shoulder (anterior-posterior, proximal, and superior-inferior) at ball release. Subsequently, the specific rotational position and range of motion of the shoulder at ball release that minimized forces on the shoulder were determined.

Results:

Statistically significant correlations were identified between the magnitude of superior-inferior force on the shoulder and shoulder abduction position (R² = 0.44, P < .001) as well as between the magnitude of anterior-posterior force on the shoulder and shoulder horizontal adduction-abduction position (R² = 0.72, P < .001). Minimal anterior-posterior and superior-inferior forces were obtained with a combination of 80.6° of shoulder abduction and 10.7° of shoulder horizontal adduction. Any deviation >5° from this position significantly increased the anterior-posterior and superior-inferior forces on the shoulder.

Conclusion:

Increasing shoulder horizontal abduction position significantly increased the magnitude of anterior force on the shoulder at ball release. The combination of 80.6° of shoulder abduction and 10.7° of horizontal shoulder adduction minimized the shear forces on the shoulder at this point.

Clinical Relevance:

The present data can be useful for screening pitching technique to prevent shoulder pain and injury with motion capture assessment.

Keywords

pitching baseball shoulder injury force shoulder horizontal abduction

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References

Tang

Yokoi

. Estimation of inertial properties of the body segments in Japanese athletes. Biomechanism. 1992;11:23-33.

Aguinaldo

Buttermore

Chambers

. Effects of upper trunk rotation on shoulder joint torque among baseball pitchers of various levels. J Appl Biomech. 2007;23(1):42-51.

Chu

Fleisig

Simpson

Andrews

. Biomechanical comparison between elite female and male baseball pitchers. J Appl Biomech. 2009;25:22-31.

Davidson

Elattrache

Jobe

. Rotator cuff and posterior-superior glenoid labrum injury associated with increased glenohumeral motion: a new site of impingement. J Shoulder Elbow Surg. 1995;4(5):384-390.

Davis

Limpisvasti

Fluhme

, et al. The effect of pitching biomechanics on the upper extremity in youth and adolescent baseball pitchers. Am J Sports Med. 2009;37(8):1484-1491.

Dun

Loftice

Fleisig

Kingsley

Andrews

. A biomechanical comparison of youth baseball pitches: is the curveball potentially harmful? Am J Sports Med. 2008;36(4):686-692.

Escamilla

Fleisig

Barrentine

Andrews

Moorman

3rd . Kinematic and kinetic comparisons between American and Korean professional baseball pitchers. Sports Biomech. 2002;1(2):213-228.

Escamilla

Barrentine

Fleisig

, et al. Pitching biomechanics as a pitcher approaches muscular fatigue during a simulated baseball game. Am J Sports Med. 2007;35(1):23-33

Fleisig

Andrews

Dillman

Escamilla

. Kinetics of baseball pitching with implications about injury mechanics. Am J Sports Med. 1995;23(2):233-239.

10.

Fleisig

Barrentine

Zheng

Escamilla

Andrews

. Kinematic and kinetic comparison of baseball pitching among various levels of development. J Biomech. 1999;32(12):1371-1375.

11.

Jobe

. Posterior superior glenoid impingement: expanded spectrum. Arthroscopy. 1995;11(5):530-536.

12.

Jobe

Giangarra

Kvitne

Glousman

. Anterior capsulolabral reconstruction of the shoulder in athletes in overhand sports. Am J Sports Med. 1991;19(5):428-434.

13.

Matsuo

Fleisig

. Influence of shoulder abduction and lateral trunk tilt on peak elbow varus torque for baseball pitchers during simulated pitching. J Appl Biomech. 2006;22(2):93-102.

14.

McFarland

. Coaching Pitchers. Champaign, IL: Human Kinetics; 1990.

15.

Mihata

McGarry

Kinoshita

Lee

. Excessive glenoumeral horizontal abduction as occurs during the late cocking phase of the throwing motion can be critical for internal impingement. Am J Sports Med. 2010;38(2):369-374.

16.

Mihata

McGarry

Neo

Ohue

Lee

. Effect of anterior capsular laxity on horizontal abduction and forceful internal impingement in a cadaveric model of the throwing shoulder. Am J Sports Med. 2015;43(7):1758-1763.

17.

Nakamizo

Nakamura

Nobuhara

Yamamoto

. Loss of glenohumeral internal rotation in little league pitchers: a biomechanical study. J Shoulder Elbow Surg. 2008;17(5):795-801.

18.

Nobuhara

. The shoulder in sports. In: Nobuhara

(Ed.). The Shoulder: Its Function and Clinical Aspects. Toh Tuck Link, Singapore: World Scientific Publishing Co; 2003.

19.

Norwood

Del Pizzo

Jobe

Kerlan

. Anterior shoulder pain in baseball pitchers. Am J Sports Med. 1978;6(3):103-105.

20.

Oliver

Keeley

. Pelvis and torso kinematics and their relationship to shoulder kinematics in high-school baseball pitchers. J Strength Cond Res. 2010;24(12):3241-3246.

21.

Oyama

Blackburn

Padua

Myers

. Effect of excessive contralateral trunk tilt on pitching biomechanics and performance in high school pitchers. Am J Sports Med. 2013;41(10):2430-2438.

22.

Paley

Jobe

Pink

Kvitne

ElAttrache

. Arthroscopic findings in the overhand throwing athlete: evidence for posterior internal impingement of the rotator cuff. Arthroscopy. 2000;16(1):35-40.

23.

Pieper

. Humeral torsion in the throwing arm of handball players. Am J Sports Med. 1998;26(2):247-253.

24.

Poppen

Walker

. Forces at the glenohumeral joint in abduction. Clin Orthop Rel Res. 1978;135:165-170.

25.

Ryu

Dunbar

5th Kuhn

McFarland

Chronopoulos

Kim

. Comprehensive evaluation and treatment of the shoulder in the throwing athlete. Arthroscopy. 2002;18(9)(suppl 2):70-89.

26.

Sabick

Kim

Torry

Keirns

Hawkins

. Biomechanics of the shoulder in youth baseball pitchers: implications for the development of proximal humeral epiphysiolysis and humeral retrotorsion. Am J Sports Med. 2005;33(11):1716-1722.

27.

Takagi

Tanaka

, et al. Increased horizontal shoulder abduction is associated with an increase in shoulder joint load in baseball pitching. J Shoulder Elbow Surg. 2014;23(12):1757-1762.

28.

Urbin

Fleisig

Abebe

Andrews

. Associations between timing in the baseball pitch and shoulder kinetics, elbow kinetics, and ball speed. Am J Sports Med. 2013;41(2):336-342.

29.

Walch

Boileau

Noel

Donell

. Impingement of the deep surface of the supraspinatus tendon on the posterosuperior glenoid rim: an arthroscopic study. J Shoulder Elbow Surg. 1992;1(5):238-245.

30.

Werner

Guido

Jr Stewart

McNeice

VanDyke

Jones

. Relationships between throwing mechanics and shoulder distraction in collegiate baseball pitchers. J Shoulder Elbow Surg. 2007;16(1):37-42.

31.

Siegler

Allard

, et al. ISB recommendation on definitions of joint coordinate system of various joints for the reporting of human joint motion—part I: ankle, hip, and spine. J Biomech. 2002;35(4):543-548.

32.

van der Helm

Veeger

, et al. ISB recommendation on definitions of joint coordinate systems of various joints for the reporting of human joint motion—part II: shoulder, elbow, wrist and hand. J Biomech. 2005;38(5):981-992.