Document Type : Original Articles
Authors
1 Department of Sport Injures and Corrective Exercises, Faculty of Physical Education & Sport Sciences, University of Guilan, Rasht, Iran.
2 Department of Physiotherapy, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
3 Department of Sport Sciences, Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, Iran. Email
Abstract
Background: The present study aimed to evaluate differences in shoulder strength, muscle length, and proprioception between the dominant and non-dominant limbs of individuals with and without uneven shoulders.
Methods: This cross-sectional comparative study included 20 females with uneven shoulders and 20 age-matched controls (aged 20–30 years), selected through purposive sampling. Shoulder asymmetry was assessed using digital photography and analyzed with AutoCAD 2020. Muscle strength was measured using a manual dynamometer, proprioception was evaluated via joint angle reconstruction errors using a goniometer, and muscle length was assessed with standardized tests. Data were analyzed using SPSS version 22.
Results: Significant differences were observed between the groups in mean error of shoulder flexion angle reconstruction (p = 0.049, d = 0.56) and internal rotation (p = 0.037, d = 0.61), as well as in the lengths of the pectoralis minor (p = 0.036, d = 0.58) and levator scapulae muscles (p = 0.021, d = 0.64). Participants with uneven shoulders exhibited greater side-to-side differences compared to the control group. No statistically significant differences were found between groups regarding shoulder strength or upper trapezius muscle length.
Conclusion: Individuals with uneven shoulders demonstrated greater errors in joint position sense and asymmetries in specific muscle lengths. These findings suggest that uneven shoulders may be associated with impaired proprioception and altered muscle length, particularly in the pectoralis minor and levator scapulae muscles.
Keywords
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