The Adapted Characteristic in the Range of Motion of the Shoulder for Young Male Volleyball Players

Background Volleyball players often repeatedly perform spiking and serving, which may lead to muscle microtrauma of the shoulder and consequently reduce shoulder joint range of motion (ROM) and increase the risk of shoulder injuries. Aims This study aimed to understand and evaluate the bilateral shoulder ROM in high school male volleyball athletes to discover the adapted characteristics. Methods Forty high school male volleyball athletes participated in this study. The shoulder ROM measurements were taken for both the dominant and non-dominant sides. The paired samples t-tests were used to analyze shoulder ROM differences between the dominant and non-dominant sides. Results The dominant side showed a significantly lower in internal rotation ( p  = .000) and total shoulder rotation ROM ( p  = .021) compared to the non-dominant side ( p  < .05). Conversely, the dominant side of the shoulder exhibited significantly greater external rotation ( p  = .001) and shoulder horizontal adduction ( p  = .000) than the non-dominant side ( p  < .05). No significant differences were found in other measured parameters. The incidence of Glenohumeral Internal Rotation Deficit (GIRD) among all subjects was 37.5%. Conclusions High school male volleyball athletes in this study exhibited tightness in the posterior shoulder of their dominant side, indicating specific adaptations in shoulder ROM and a considerable prevalence of GIRD, observed in approximately one-quarter of the athletes. It is recommended to incorporate stretching and eccentric muscle training focusing on the posterior shoulder to mitigate these adaptations and reduce the risk of shoulder injuries.