IMR Press / JOMH / Volume 17 / Issue 3 / DOI: 10.31083/jomh.2021.030
Open Access Original Research
The relationship between range of motion and muscle strength of the shoulder joint in professional baseball pitchers
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1 QOLFIT Training Center, Seoul, Republic of Korea
2 Department of Clinical Research Design and Evaluation, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea
3 Patient-Centered Outcomes Research Institute, Samsung Medical Center, Seoul, Republic of Korea
4 Department of Exercise Prescription, Dongshin University, Naju, Republic of Korea
*Correspondence: (Seung Kil Lim)
J. Mens. Health 2021, 17(3), 160–166;
Submitted: 10 January 2020 | Accepted: 9 February 2021 | Published: 8 July 2021
Copyright: © 2021 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license (

Background and objective: This study aimed to assess the relationship between range of motion (ROM) and isometric strength of the shoulder joint, adjusted for humeral head retroversion angle (HHRA), in professional baseball pitchers.

Material and Methods: A total of 18 pitchers from a professional baseball team were included in this study. The isometric strength of internal rotation (IR) and external rotation (ER) were measured using an isokinetic device at 85 and 30 ER, and at 25 IR. A linear regression analysis was then performed.

Results: The HHRA of the dominant arm was approximately 7 greater than that of the non-dominant arm (P < 0.001). As the IR ROM increased by 1, the IR isometric strength at 25 IR was significantly increased by 0.448% body weight (P < 0.05). However, as the ROM of IR increased, the IR isometric strength at 85 and 30 ER was not significant (P > 0.05), and as the ROM of ER increased, the IR and ER isometric strength were not significant (P > 0.05).

Conclusions: Thus, the increase of IR ROM in professional baseball pitchers was associated with an increase in isometric strength at 25 IR, after adjustments were made for HHRA.

Humeral retroversion
Range of motion
Internal rotation
External rotation
Muscle strength
Baseball pitchers
Fig. 1.
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