Using a Wearable Device to Assist the Training of the Throwing Motion of Baseball Players

Background: Alterations in glenohumeral internal rotation (GIR), glenohumeral external rotation (GER), and the total arc of motion (TAM) have been linked with increased injury risk in the shoulder and elbow. These motions have been routinely measured with the forearm in neutral rotation (GIRN, GERN, TAMN). GER capacity appears to be especially important. The throwing motion, however, requires forearm pronation as GER occurs to achieve optimal cocking (GERP). No previous studies have evaluated GERP to determine GER capacity or pronated TAM (TAMP) values. Hypothesis: There would be significant differences between GERN and TAMN and between GERP and TAMP. Study Design: Cross-sectional. Level of Evidence: Level 3. Methods: Sixty asymptomatic male Minor League Baseball players (32 pitchers, 28 position players) participated in the study and were tested on the first day of spring training. Passive range of motion measurements were recorded using a long-arm bubble goniometer for GIRN, GERN, and GERP on both arms. TAM was calculated separately as the sum of internal and external rotational measurements under neutral and pronated conditions. Results: Within pitchers and position players, all measurements were statistically reduced for the throwing arm ( P ≤ 0.03) except for GERN of the pitchers. GERP measures were significantly less than GERN for both arms of each group ( P < 0.01): pitchers throwing arm +11.8°/nonthrowing arm +4.8°, position players throwing arm = +8.6°/nonthrowing arm +4.0°. Conclusion: The forearm position of pronation, which appears to be mediated by tightness of the biceps, decreases GER capacity and TAM. GER and TAM should be calculated in neutral and pronated positions, considering that 80% of the players have a demonstrated difference between 8° and 12°. Clinical Relevance: Measurement of GERP more accurately reflects the GER required in throwing, allows better quantification of the motion capacity necessary to withstand the loads in throwing, and may suggest interventions for at risk athletes.

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A wearable device for estimating throwing motion based on electrical impedance measurement in the wrist

The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) ◽

10.1299/jsmermd.2021.1p2-e08 ◽

2021 ◽

Vol 2021 (0) ◽

pp. 1P2-E08

Author(s):

Kazuma TAKAISHI ◽

Taku HACHISU ◽

Masakazu HIROKAWA ◽

Kenji SUZUKI

Keyword(s):

Electrical Impedance ◽

Impedance Measurement ◽

Wearable Device ◽

Electrical Impedance Measurement ◽

Throwing Motion

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Little Leaguer’s Shoulder Caused Severe Humeral Retroversion: Ultrasonographic Analysis

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00439 ◽

2019 ◽

Vol 7 (7_suppl5) ◽

pp. 2325967119S0043

Author(s):

Teruhisa Mihata ◽

Masashi Neo

Keyword(s):

High School ◽

Junior High ◽

T Test ◽

Control Group ◽

Baseball Players ◽

Little Leaguer’S Shoulder ◽

Humeral Retroversion ◽

And Control ◽

Dominant Side ◽

Throwing Motion

Objectives: The increased humeral retroversion on the dominant side in throwing athletes is thought to result from repetitive throwing motion. In the previous studies, the degree of increased humeral retroversion was various, suggesting that other factors may affect humeral retroversion. Little Leaguer’s shoulder, which is rotational stress fracture of the proximal humeral epiphyseal plate, may change humeral retroversion. The purpose of this study was to investigate effect of Little Leaguer’s shoulder on humeral retroversion. Methods: Ten high-school baseball players (average, 16.6 years; range, 16 to 18 years), who had had Little Leaguer’s shoulder during elementary or junior high schools (average, 12.6 years; range, 11 to 15 years), were enrolled in the study. As a control group, 22 high-school baseball players (average, 16.9 years; range, 16 to 18 years), who have never had shoulder or elbow pain, were included in this study. Humeral retroversion was ultrasonographically measured on the dominant and non-dominant sides. Humeral retroversion was compared between dominant and non-dominant shoulders with paired t-test. Side-to-side difference in humeral retroversion was compared between Little Leaguer’s shoulders and control group with unpaired t-test. Results: Humeral retroversion was significantly greater on the dominant side than on the non-dominant side in both Little Leaguer’s shoulder (Dominant, 104°±8°; Non-dominant, 84°±12°; P < .001) and control groups (Dominant, 91°±13°; Non-dominant, 81°±10°; P < .001). The side-to-side difference in humeral retroversion in Little Leaguer’s shoulder group (20°±10°) was significantly greater than that in control group (10°±10°, P = .02). Conclusion: Humeral retroversion was increased with repetitive throwing motion without any symptom in the shoulder and elbow joint. Additional increase in humeral retroversion was made when the players had had Little Leaguer’s shoulder in elementary or junior high school.

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Characteristics Of Trunk Rotation Movement During The Throwing Motion In semale Baseball Players

Medicine & Science in Sports & Exercise ◽

10.1097/00005768-200505001-00607 ◽

2005 ◽

Vol 37 (Supplement) ◽

pp. S118???S119

Author(s):

Hirokazu Ito ◽

Koichi Nakazato ◽

Koji Watarai ◽

Hiroyuki Nakajima

Keyword(s):

Trunk Rotation ◽

Baseball Players ◽

Throwing Motion

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Effect of Throwing Kinematics and Kinetics on Different Ranges of Long Toss in Youth Baseball Players

Proceedings ◽

10.3390/proceedings2020049118 ◽

2020 ◽

Vol 49 (1) ◽

pp. 118 ◽

Cited By ~ 1

Author(s):

Katsutoshi Nishino ◽

Noriaki Yamamoto ◽

Masaei Tanaka ◽

Taisuke Ohishi ◽

Yasuo Tanaka ◽

...

Keyword(s):

The Other ◽

Physical Growth ◽

Baseball Players ◽

Youth Baseball ◽

Baseball Coaches ◽

Kinematics And Kinetics ◽

Throwing Motion

Long-toss throwing is a baseball exercise that enhances the throwing performance of youth players. However, throwing kinematics and kinetics have not been fully investigated. This study aimed to analyze the effect of throwing kinematics and kinetics on different ranges of long toss in 22 youth players of the same age. The throwing motion was analyzed as the range of long toss was increased by 10 m each time until the ball did not directly reach the target. The twelve subjects who could throw long distances had a significantly larger physique and larger throwing kinematics and kinetics compared to the other 10 subjects who could not. No differences in the proximal force of the shoulder and elbow joints were observed between the two groups. These findings suggest that baseball coaches should set a suitable range of long toss for youth players according to the individual’s physical growth and strength.

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Lack of a Relationship Between Glenohumeral External-Rotation Strength and Posterior Shoulder Tightness in Baseball Players

Journal of Sport Rehabilitation ◽

10.1123/jsr.21.1.12 ◽

2012 ◽

Vol 21 (1) ◽

pp. 12-17 ◽

Cited By ~ 6

Author(s):

Kevin G. Laudner ◽

Mike Moline ◽

Keith Meister

Keyword(s):

Internal Rotation ◽

Outcome Measures ◽

External Rotation ◽

Professional Baseball ◽

Baseball Players ◽

Shoulder Range Of Motion ◽

Posterior Shoulder ◽

Rotation Strength ◽

Posterior Shoulder Tightness ◽

Throwing Motion

Context:Posterior shoulder tightness has been associated with altered shoulder range of motion (ROM) and several pathologic entities in baseball players. This tightness is hypothesized to be the result of the cumulative stress placed on the posterior shoulder during the deceleration phase of the throwing motion. The role of the posterior shoulder static restraints is to absorb this load while the glenohumeral (GH) external rotators eccentrically decelerate the arm after ball release and therefore also help dissipate this force. As such, the authors hypothesized that if the GH external rotators are weak, an excessive amount of this deceleration force is placed on the static restraints, which may lead to subsequent tightness.Objective:To compare the relationship between GH external-rotation strength and posterior shoulder tightness as measured by GH horizontal-adduction and internal-rotation ROM.Design:Descriptive study.Setting:Laboratory.Participants:45 professional baseball players.Main Outcome Measures:GH external-rotation strength and GH horizontal-adduction and internalrotation ROM.Results:GH external-rotation strength showed no relationship with either GH horizontal-adduction ROM (r2 = .02, P = .40) or GH internal-rotation ROM (r2 = .002, P = .77).Conclusion:There is little to no relationship between GH external-rotation strength and posterior shoulder tightness in professional baseball players. The posterior static restraints of the shoulder may absorb a large majority of the deceleration forces during the throwing motion. Although strengthening of the posterior shoulder dynamic restraints should not be overlooked, routine stretching of the static restraints may be more beneficial for decreasing posterior shoulder tightness and the subsequent risks associated with this tightness, although future research is warranted.

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