Mechanical Hyperalgesia but Not Forward Shoulder Posture Is Associated with Shoulder Pain in Volleyball Players: A Cross-Sectional Study

Abstract

[Abstract] Shoulder antepulsion, altered scapular kinematics and imbalance of muscle activity are commonly associated with shoulder pain. This study aimed to observe if there is an association between the forward shoulder angle (FSA) and the pectoralis minor length index (PMI) in volleyball players with and without shoulder pain. Furthermore, this study observed if there is an association between shoulder posture and upper limb mechanical hyperalgesia in volleyball players with and without shoulder pain. Methods: a cross-sectional study was conducted in the Physiotherapy and Pain Research Center in Alcalá de Henares (Spain). A total of 56 volleyball players met the inclusion criteria and agreed to enter the study. Subjects were divided into two groups: shoulder pain group (SPG) and control group (without pain). The following measurements of the dominant sides of the players were collected: FSA, PMI, and pressure pain threshold (PPT) in serratus anterior, lower trapezius, infraspinatus, teres minor, upper trapezius, levator scapulae, pectoralis major, radial nerve, cubital nerve, and median nerve. Results: The Spearman’s Rho revealed no significant correlations were found between FSA and PMI. Moreover, Spearman’s Rho test revealed in the SPG a negative moderate correlation between FSA and Infraspinatus-PPT (Rho = −0.43; p = 0.02); FSA and levator scapulae-PPT (Rho = −0.55; p < 0.01); FSA and pectoralis major-PPT (Rho = −0.41; p = 0.02); PMI and cubital nerve-PPT (Rho = −0.44; p = 0.01). Conclusions: No association was found between the forward shoulder angle and the pectoralis minor index in volleyball players with and without shoulder pain. There is a moderate negative association between shoulder forward angle and muscle mechanical hyperalgesia in volleyball players with shoulder pain, but no such associations were found in volleyball players without shoulder pain. Treatment of the infraspinatus, levator scapulae, pectoralis major, and pectoralis minor muscles could improve shoulder pain and ulnar nerve mechanosensitivity.