Comparison of Scapulohumeral rhythm in individuals with and without Forward Shoulder Posture [version 1; peer review: awaiting peer review]

Background Forward Shoulder Posture (FSP) is one of the most common postural deviations of the upper back, which may affect the scapulohumeral rhythm (SHR). This study aimed to investigate changes in scapulohumeral rhythm during scapular plane shoulder abduction between individuals with and without FSP. Methods A cross sectional study with two group comparison. Young adults with FSP (N=39) with a forward shoulder angle ≥ 52°and without FSP(N=40) with a forward shoulder angle < 52° were recruited for the study. Scapular upward rotation was measured with the help of two inclinometers during scapular plane shoulder abduction, at resting shoulder abduction, at 30°, 60°, 90°, 120°, 150°, and at full range of shoulder abduction, and SHR was calculated. The scapulohumeral rhythm was compared between the two groups using an independent t test. Results Data analysis showed a statistically significant difference in scapulohumeral rhythm at 30°(p=0.004), 60°(p=0.013), and 90°(p=0.009) shoulder abduction between the two groups. There were no significant differences in the other ranges of shoulder abduction between the two groups. Conclusion Forward shoulder posture alters the scapulohumeral rhythm between 30 ° and 90°shoulder abduction. Clinicians, trainers, and sports therapists should be aware of this change to intervene at an early stage and prevent the development of pathological conditions around the shoulder.