Incidence of rotator cuff muscle imbalance and shoulder pain in female volleyball players

Abstract

Objective: To compare shoulder muscle imbalance present in volleyball attackers who perform a lot of overhead movements to athletes who do not. This study also investigates if muscle imbalance is linked to a history of shoulder pain. Method: 5 volleyball and 5 football athletes had their isometric lateral rotator (LR) and medial rotator (MR) strengths measured using a handheld dynamometer in two positions: neutral position with 0° of abduction and 90° of abduction with 90° of lateral rotation (90-90). The participants were also asked to fill in a questionnaire about any history of shoulder pain. Results: The participants had a mean age of 22.3 years old, a mean height of 168.4 cm, and a mean weight of 61.42 kg. All the participants in this study were right hand dominant. The MR were stronger in volleyball players regardless of the position and shoulder tested. On the contrary the LR of volleyball players were stronger in the neutral position but not in the more functional abducted position. Despite this, the LR/MR ratio was similar between the two groups. In the abducted position the volleyball players were found to have a ratio of 0.75 in the dominant arm and 0.67 in the non-dominant arm. In the neutral position the volleyball group had a ratio of 0.78 in the dominant arm and 0.79 in the non-dominant arm. Conclusion: In this study volleyball players were not more likely to have a shoulder imbalance and it was not linked to a history of pain, however these results should be interpreted with caution due to the small sample size.