Objective: A common cause of shoulder joint pain in this population is subacromial impingement, often associated with increased thoracic kyphosis. However, the association between thoracic kyphosis angle and shoulder joint pain in competitive swimmers remains uncertain. The aim of this study was to investigate factors associated with shoulder joint pain in male competitive swimmers, considering both previously reported variables and the thoracic kyphosis angle. Design: Cross-sectional observational study. Setting: Poolside at the participants' school. Participants: A total of 64 male university and adult swimmers participated. Independent Variables: Participants were divided into Group P (with shoulder joint pain) and Group N (without shoulder joint pain). Main Outcome Measures: Measurements included external and internal rotation range of motion (ROM) at 90 degrees shoulder abduction (Abd90°ER and Abd90°IR), internal rotation ROM at 90 degrees shoulder flexion (Flex90°IR), scapular dyskinesis (SD) test, shoulder rotation width, lumbar locked rotation, and thoracic kyphosis angle. The significance level was set at <5%. Results: Four variables exhibited significant differences between groups: Abd90°IR (median, 95% confidence interval [CI]): Group P, 66.0 degrees [57.7 degrees–68.5 degrees] versus Group N, 76.0 degrees [69.5 degrees–78.0 degrees]; Flex90°IR (median [95% CI]): Group P, 16.0 degrees [8.4 degrees–17.0 degrees] versus Group N, 25.0 degrees [23.1 degrees–27.1 degrees]; thoracic kyphosis angle (median [95% CI]): Group P, 23.1 degrees [20.4 degrees–25.9 degrees] versus Group N, 19.4 degrees [17.6 degrees–21.1 degrees]; and SD (positive test result in 15 of 27 patients in Group P vs 11 of 37 in Group N). Conclusions: Shoulder joint pain in competitive swimmers may be associated with an increased thoracic kyphosis angle during upper limb elevation, SD, and reduced shoulder ROM.
