Kinematics and Muscle Performance of the Trunk and Shoulder in Volleyball Players With Subacromial Impingement Syndrome

Volleyball players repetitively place the arm into extreme positions, and thus expose the athletes' shoulders to a large load and increase the risk of injuries. The shoulder complex is identified as one of the most injured joints in volleyball sports. Although many studies have revealed alterations in the function, morphology and biomechanics of the shoulder complex in volleyball players with shoulder pain, some researchers suggested that a smooth energy transfer from the axial skeleton, through the shoulder complex, to the arm and hand is crucial for overhead sports performance and injury prevention, with little evidence showing the link between trunk muscle performance and shoulder pain in volleyball players. Therefore, the main purposes of present study are (1) to compare the trunk muscle performance (muscle strength, power and endurance) in volleyball players with and without subacromial impingement syndrome (SIS); (2) to compare trunk and shoulder muscles activity during spiking in volleyball players with and without SIS.