SUMMARY
Background and purpose. Many regularly performed spikes and serves lead to a shoulder girdle adaptation that could be sport-specific and result in traumatic events.
The aim was to evaluate shoulder joints’ range of movements (ROM), peak isometric strength of arm muscles, submaximal force repetition error, and upper body dynamic stability in adolescent female volleyball players.
Materials and methods. 15 qualified, 17.7 ± 2.1-year-old, female volleyball players participated. The shoulder active ROM of internal rotation (IR), external rotation (ER), flexion, extension, abduction, adduction, horizontal abduction (HABD), and horizontal adduction (HADD) were measured. The peak force and the ability to repeat the same submaximal force of IR, ER, and extension were determined. Dynamic stability was detected by the Y-upper-body dynamic balance test (Y-UBDST).
Results. The ER ROM was increased but the IR and HADD ROMs were decreased on both shoulders. The extension and adduction ROMs were smaller in the dominant (D) shoulder (p < 0.05). The D arm’s IR, ER, and extension muscles developed greater peak forces (p < 0.05). ER/IR muscles’ peak forces ratio was 0.94 ± 0.18 in both shoulders. The ER and extension muscles submaximal force repetition error was smaller in the D arm (p < 0.05). The mean score of the normalized reaching distances in the Y-UBDST was symmetrical: 95 ± 6% in the D and 94 ± 7% in the non-dominant (ND) arm. The correlation between the rotators’ peak force and the Y-UBDBT was not significant.
Conclusions. The shoulder girdle characteristics were optimal and adaptable for volleyball spike and serve movements in those adolescent qualified female volleyball players without pathological changes in pre-season.

Keywords: Muscles strength, proprioception., range of movements, shoulder, volleyball,