Comparison of OnBaseU Tests with Pitching Motion Analysis in Youth Baseball Pitchers

Background The effects of repetitive throwing on the shoulders of developing athletes are not well understood because of the paucity of data describing the biomechanics of youth pitchers and the plasticity of the developing skeleton. Hypothesis The direction and magnitude of the stresses that exist at the proximal humeral physis during the fastball pitching motion are consistent with the development of proximal humeral epiphysiolysis (Little League shoulder) and/or humeral retrotorsion. Study Design Descriptive laboratory study. Methods A total of 14 elite youth baseball pitchers (mean age, 12.1 ± 0.4 years) were filmed from the front and dominant side while throwing fastballs in a simulated game. The net force and torque acting on the humerus throughout the throwing motion were calculated using standard biomechanical techniques. Results The external rotation torque about the long axis of the humerus reached a peak value of 17.7 ± 3.5 N.m (2.7% ± 0.3% body weight × height) just before maximum shoulder external rotation. A shoulder distraction force of 214.7 ± 47.2 N (49.8% ± 8.3% body weight) occurred at, or just after, ball release. Conclusion Shear stress arising from the high torque late in the arm-cocking phase is large enough to lead to deformation of the weak proximal humeral epiphyseal cartilage, causing either humeral retrotorsion or proximal humeral epiphysiolysis over time. The stresses generated by the external rotation torque are much greater than those caused by distraction forces generated during the pitching motion of youth baseball pitchers. Clinical Relevance The motion of throwing fastballs by youth baseball pitchers results in force components consistent with proposed mechanisms for 2 clinical entities.

Download Full-text

The Effect of Pitching Biomechanics on the Upper Extremity in Youth and Adolescent Baseball Pitchers

The American Journal of Sports Medicine ◽

10.1177/0363546509340226 ◽

2009 ◽

Vol 37 (8) ◽

pp. 1484-1491 ◽

Cited By ~ 124

Author(s):

J.T. Davis ◽

Orr Limpisvasti ◽

Derrick Fluhme ◽

Karen J. Mohr ◽

Lewis A. Yocum ◽

...

Keyword(s):

Upper Extremity ◽

Internal Rotation ◽

Motion Analysis ◽

High Speed ◽

Elbow Pain ◽

Correct Performance ◽

Youth Baseball ◽

Elbow Injuries ◽

Baseball Pitchers ◽

Analysis System

Background Increased pitch counts have been linked to increased complaints of shoulder and elbow pain in youth baseball pitchers. Improper pitching mechanics have not been shown to adversely affect the upper extremity in youth pitchers. Hypothesis The correct performance of 5 biomechanical pitching parameters correlates with lower humeral internal rotation torque and elbow valgus load, as well as higher pitching efficiency, in youth and adolescent pitchers. Study Design Descriptive laboratory study. Methods In sum, 169 baseball pitchers (aged 9-18) were analyzed using a quantitative motion analysis system and a high-speed video while throwing fastballs. The correct performance of 5 common pitching parameters was compared with each pitcher's age, humeral internal rotation torque, elbow valgus load, and calculated pitching efficiency. Results Motion analysis correlated with video analysis for all 5 parameters (P <. 05). Youth pitchers (aged 9-13) performing 3 or more parameters correctly showed lower humeral internal rotation torque, lower elbow valgus load, and higher pitching efficiency (P <. 05). Conclusions Youth pitchers with better pitching mechanics generate lower humeral internal rotation torque, lower elbow valgus load, and more efficiency than do those with improper mechanics. Proper pitching mechanics may help prevent shoulder and elbow injuries in youth pitchers. Clinical Relevance The parameters described in this study may be used to improve the pitching mechanics of youth pitchers and possibly reduce shoulder and elbow pain in youth baseball pitchers.

Download Full-text

Comparison of OnBaseU Tests with Biomechanical Motion Analysis in Youth Baseball Pitchers

International Journal of Sports Physical Therapy ◽

10.26603/001c.29519 ◽

2021 ◽

Author(s):

Tessa Hulburt ◽

Taylor Catalano ◽

Kristen F. Nicholson

Keyword(s):

Motion Analysis ◽

Youth Baseball ◽

Baseball Pitchers

Download Full-text

Limiting the Pitch Count in Youth Baseball Pitchers Decreases Elbow Pain

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967121989108 ◽

2021 ◽

Vol 9 (3) ◽

pp. 232596712198910

Author(s):

Tetsuya Matsuura ◽

Yuki Takata ◽

Toshiyuki Iwame ◽

Jyoji Iwase ◽

Kenji Yokoyama ◽

...

Keyword(s):

Range Of Motion ◽

Stress Test ◽

Daily Maximum ◽

Test Results ◽

Level Of Evidence ◽

Valgus Stress ◽

Radiographic Images ◽

Elbow Pain ◽

Youth Baseball ◽

Baseball Pitchers

Background: Reducing the number of pitches thrown is regarded as the most effective way to prevent throwing injuries in youth baseball pitchers. However, few studies have compared the effectiveness of limiting the pitch count versus the limiting the number of innings pitched in terms of elbow injuries. Hypothesis: We hypothesized that, compared with inning limits, pitch count limits would lead to greater decreases in elbow pain, range of motion deficits, positive moving valgus stress test results, and the risk of capitellar osteochondritis dissecans (OCD). Study Design: Cohort study; Level of evidence, 3. Methods: This study retrospectively reviewed baseball pitchers aged 8 to 12 years in 2017 and 2018. Inning and pitch count limits in games were set to a daily maximum of 7 innings in 2017 and 70 pitches in 2018. Elbow pain, range of motion, and moving valgus stress test results were evaluated. The presence of capitellar OCD was assessed on ultrasonographic and radiographic images. Results: A total of 352 pitchers in 2017 and 367 pitchers in 2018 participated. The mean pitch count per game was lower in the pitch count limit (CL) group (52.5 ± 16.0) than in the inning limit (IL) group (98.2 ± 19.5) ( P < .001). Compared with the IL group, the CL group had significantly lower rates of elbow pain (40.9% vs 31.9%, respectively; P = .01) and reduced flexion (19.0% vs 10.6%, respectively; P = .001). Multivariate analysis revealed a significant association between elbow pain and age in both the IL and the CL groups ( P < .0001 and P = .02, respectively) and between OCD and elbow pain in the CL group ( P = .04). Conclusion: A pitch count limit of ≤70 pitches per day for baseball pitchers ≤12 years could be more protective against elbow pain and reduced flexion than a limit of ≤7 innings per day, but it may not be effective for reducing the risk of capitellar OCD.

Download Full-text

Asymmetry and evolution over a one-year period of the upward rotation of the scapula in youth baseball pitchers

International Biomechanics ◽

10.1080/23335432.2018.1499441 ◽

2018 ◽

pp. 1-6

Author(s):

Erik van der Graaff ◽

Bengt Kom ◽

Femke van Dis ◽

Xavier Gasparutto ◽

Marco Hoozemans ◽

...

Keyword(s):

Youth Baseball ◽

Baseball Pitchers ◽

One Year

Download Full-text

Pitching Practices and Self-Reported Injuries Among Youth Baseball Pitchers: A Descriptive Study

Athletic Training & Sports Health Care ◽

10.3928/19425864-20110331-01 ◽

2011 ◽

Vol 4 (1) ◽

pp. 11-20 ◽

Cited By ~ 25

Author(s):

Johna K. Register-Mihalik ◽

Sakiko Oyama ◽

Stephen W. Marshall ◽

Frederick O. Mueller

Keyword(s):

Descriptive Study ◽

Youth Baseball ◽

Baseball Pitchers

Download Full-text

An efficient multi-factor geometry optimization based on motion analysis and resonance response for hinged double-body floating wave energy converter

Science Progress ◽

10.1177/0036850420950151 ◽

2020 ◽

Vol 103 (3) ◽

pp. 003685042095015

Author(s):

Biao Li ◽

Fangfang Sui ◽

Bingsong Yang

Keyword(s):

Motion Analysis ◽

Wave Energy ◽

Geometry Optimization ◽

Geometric Optimization ◽

Wave Energy Converter ◽

Geometrical Parameters ◽

Optimization Strategy ◽

Energy Converter ◽

Pitching Motion ◽

Resonance Response

In the practical engineering applications of multi-body floating wave energy converter (WEC), the traditional geometric optimization is always expensive and time-consuming. This study aim to propose a more efficient geometry optimization strategy with a hinged double-body floating WEC as the study object. The influences of geometric parameters of the buoys on the pitching motion and energy conversion ability are analyzed by numerical simulation. Simulation results show that the resonance state of the pitching motion of the buoys mainly depends on their radius and draft rather than the length; But the length of the buoys, rather than the radius and draft, always has a significant effect on the pitching phase difference of the adjacent buoys. Based on the motion analysis and resonance response, an efficient multi-factor geometry optimization strategy is put forwarded. By the strategy, the sub-optimal and optimal geometrical parameters are solved out quickly at several typical wave conditions of China Seas. The results indicate that the optimal total length of WEC is approximately equal to the wave length. The optimal diameter of buoys is about 25% of the length of buoys. And the optimal draft should attain about 61% of the diameter.

Download Full-text