The effect of glenohumeral internal rotation deficit on the isokinetic strength, pain, and quality of life in male high school baseball players.
OBJECTIVE
To investigate the effects of glenohumeral internal rotation deficit (GIRD) on the isokinetic strength, body pain, and the quality of life in male high school baseball players of Korea.


METHODS
Fifty-six male high school baseball players were divided into either group A (GIRD≥20°, n=12) or group B (GIRD<20°, n=44). The range of motion in the shoulder and the isokinetic strength were measured. Questionnaires were administered regarding the body pain location by using the visual analogue scale, and the quality of life was measured by using the SF-36 Form.


RESULTS
All subjects had increased external rotation range of motion and decreased internal rotation in the throwing shoulder. The incidence of GIRD (≥20°) was 21.43% in the present study. In the isokinetic strength test, a significantly weaker muscular state at an angular velocity of 180°/s was observed in group A, compared to group B. For the comparison of the pain, the frequency of shoulder pain was higher (33.93%) than other body pain, among the study subjects.


CONCLUSIONS
GIRD is one of the main risk factors of glenohumeral joint damage, and it is correlated with reduced isokinetic strength and quality of life. High school baseball players will need appropriate shoulder rehabilitation programs for the improvement in their quality of life and performance.
Department of Physical Medicine and Rehabilitation, Sahmyook Medical Center, Seoul, Korea.
Jinyoung
J
Lee
Department of Physical Medicine and Rehabilitation, Sahmyook Medical Center, Seoul, Korea.
Li-Na
LN
Kim
Korea Institute of Sports Science, Seoul, Korea.
Hongsun
H
Song
Department of Physical Medicine and Rehabilitation, Sahmyook Medical Center, Seoul, Korea.
Sunghwan
S
Kim
Institute of Health and Exercise, Seoul National University, Seoul, Korea.
Seungseok
S
Woo
Baseball; Glenohumeral joint; Quality of life; Shoulder joint; Shoulder pain