Relationship between throwing mechanics and elbow valgus in professional baseball pitchers

doi:10.1067/mse.2002.121481

Journal of Shoulder and Elbow Surgery

Volume 11, Issue 2, March–April 2002, Pages 151-155

https://doi.org/10.1067/mse.2002.121481 Get rights and content

Abstract

Valgus elbow stress leads to medial tension and lateral compression injuries in baseball pitchers of all ages. This study was undertaken to investigate the relationship between elbow stress in professional baseball pitchers and the kinematic parameters of pitching mechanics. This was done in an attempt to understand valgus extension overload better and in an effort to improve preventive and rehabilitative protocols. High-speed video data were collected on 40 professional pitchers in game situations during the 1998 and 1999 Cactus League season in Arizona, as part of Major League Baseball Spring Training. A multiple linear regression analysis was used to relate elbow valgus to kinematic parameters of pitching mechanics. The resulting analysis produced an adjusted multiple R² value of 0.974, indicating that nearly 100% of the variance in valgus stress on the elbow was explained by the parameters in the regression equation. This ability to explain over 97% of the variance in valgus stress is significant. The parameters of pitching mechanics related to elbow valgus may be assessed and optimized, if necessary, in order to decrease the magnitude of elbow stress in pitching. (J Shoulder Elbow Surg 2002;11:151-155)

Section snippets

Methods

Forty professional baseball pitchers served as subjects in the study. Mean age was 28 ± 5 years (range, 20-37 years), with a mean height and mass of 188 ± 5 cm and 90 ± 10 kg, respectively. Thirty-two were right-handed, and 8 left-hand dominant. Data were collected in game situations during the 1998 Cactus League season in Arizona as part of Major League Baseball Spring Training. The method of data collection involved the use of three 120-Hz cameras (Peak Performance Technologies, Englewood,

Results

The mean ball velocity at REL for the 40 fastballs was 40 ± 1 m/s (89 ± 3 mph). Valgus stress at the elbow joint was thought to be indicative of injury potential and chosen as the dependent variable because this load has been associated with subsequent medial tension and lateral compressive pathologies.11, 12 Table II depicts ANOVA for the final model.

. ANOVA summary for elbow valgus multiple regression analysis

Source	Sum of squares	df	Mean square	F statistic
Regression	9912.81	4	2478.20	324.14*
Residual

Discussion

It is well accepted that the baseball pitching motion places tremendous stress on the elbow joint. The term valgus extension overload is commonly used to describe this stress. Several biomechanical studies1, 2, 3, 5, 11, 13 have documented valgus loads in excess of 115 Nm over the medial elbow near the instant of maximum external rotation. Clinicians dealing with overhead throwers are particularly cognizant of the susceptibility of these athletes to medial tension/lateral compression injuries

Acknowledgements

We wish to acknowledge Cindy Suplizio, MS; Mike Decker, MS, from Lower Extremity Research, Steadman-Hawkins Sports Medicine Foundation, Vail, Colo, and Mike Keirns, PT, Regis University, Denver, Colo, for their assistance in data collection.

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Am J Sports Med
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There are more references available in the full text version of this article.

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Organizational risk profiling and education appear to reduce professional pitching overall and 7-27-day upper extremity injury risk by 33%-38%. There was no difference in trunk and lower extremity injuries over the period, strengthening the reduction in upper extremity injury risk results. This suggests that while injury risk increased over time, organizational risk profiling mitigated the expected increase in upper extremity injury rates. Risk profiling and education can be used as a clinical screening and intervention tool to help decrease upper extremity injuries in professional baseball populations.
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Citation Excerpt :
Although pitching kinetics did not differ directly between groups, HiCon pitchers may indirectly promulgate lower injury risk by means of potentially throwing less pitches per inning, game, and/or season. HiCon pitchers may transfer energy more efficiently through the kinetic chain by delaying the timing of maximal lead hip flexion.1,38,55 When the pelvis rotates over the braced leg smoothly, greater pitch location consistency may be achieved from enhanced stability.
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Pitchers who sustained an initial lower extremity or trunk injury demonstrated an increased subsequent arm injury hazard compared with pitchers who did not. Pitchers who sustained an initial shoulder injury demonstrated a greater hazard of sustaining a subsequent arm injury compared with pitchers who sustained an initial elbow injury. However, this secondary analysis should be interpreted with caution. Clinicians should monitor risk with workload accumulation, which may be related to pitching compensatory strategies in a fatigued state. Pitchers who sustain a shoulder injury should be evaluated and perform both shoulder and elbow rehabilitation strategies before return to sport.

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^*: Reprint requests: Sherry L. Werner, PhD, Tulane Institute of Sports Medicine, 202 McAlister Extension, New Orleans, LA 70118 (E-mail: [email protected]).

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Original articleRelationship between throwing mechanics and elbow valgus in professional baseball pitchers*

Abstract

Section snippets

Methods

Results

Discussion

Acknowledgements

Orthop Clin North Am

Kinematic and kinetic parameters of the shoulder joint during the overarm baseball throw [master's thesis]

Dynamics of the shoulder and elbow joints of the throwing arm during a baseball pitch

Int J Sport Biomech

Three-dimensional interactions in a two-segment kinetic chain. Part I: General model

Int J Sport Biomech

Proper mechanics for baseball pitching

Clin Sports Med

Kinetics of baseball pitching with implications about injury mechanisms

Am J Sports Med

Original article
Relationship between throwing mechanics and elbow valgus in professional baseball pitchers*