Comparison of shoulder range of motion, strength, and endurance in amateur pitchers practicing repetitive overhead throwing

• Published in: Isokinetics and exercise science 2013-01, Vol.21 (2), p.135-140
• Main Authors: Yu, Jae-Ho, Lee, Gyu-Chang
• Format: Article
• Language: English
• ISSN: 0959-3020; 1878-5913
• DOI: 10.3233/IES-130489

BACKGROUND: A decrease in the range of internal rotation known as glenohumeral internal rotation deficit (GIRD) which caused by repetitive overhead throwing is known to take place in elite baseball players. However few attempts at studying the differences in the range of motion (ROM), muscle strength, and endurance according to the duration of the involvement of players have been made. OBJECTIVE: To investigate the difference in ROM, muscle strength, endurance of shoulder among amateur pitchers. METHOD: Forty-two right-handed amateur pitchers in their 20 s and 30 s, with similar physical characteristics participated in the study. They were divided into three groups according to their pitching experience. Range of motion, shoulder external and internal strength and endurance and grip strength were measured and compared. RESULTS: The ROM was significantly different among the 3 groups (P 0.05), especially with respect to external rotation, internal rotation, and external rotation on side-lying. The peak torque of the right external rotators differed significantly between 2 and 3 year experience groups (P 0.05). Further, the peak torque and the endurance of external rotator significantly differed between dominant and non-dominant shoulders in between 1 year group and 2 years group (P 0.05). In external rotation endurance, there were significant differences between the 1 and 2 years groups, and between the 2 and 3 years group (P 0.05). CONCLUSIONS: In conclusion, repetitive overhead throwing for more than a year caused structural changes in shoulder joints, which were possible responsible for changes in the range of motion and decrease external rotators performance. Such changes in the shoulder could generate a pattern shift in motion and cause secondary injuries such as internal impingement syndrome.