Musculoskeletal and Functional Shoulder Characteristics in Resistance-Trained Practitioners With and Without Symptoms and in Untrained Individuals
Weight training; shoulder joint; rotator cuff; musculoskeletal pain; physical functional performance
Introduction: Resistance training is widely practiced and frequently associated with neuromuscular adaptations. However, it remains unclear whether individuals with shoulder symptoms present musculoskeletal and functional shoulder differences compared with asymptomatic practitioners and untrained individuals. In addition, the influence of sex on these characteristics remains poorly explored. Objective: the purpose of this study was to compare shoulder range of motion (ROM), isometric muscle strength, strength ratios, functional performance, and postural characteristics among symptomatic and asymptomatic resistance-trained (RT) practitioners and asymptomatic untrained individuals, while also examining sex-related differences. Methods: this cross-sectional study included 157 participants (74 females, 83 males) classified into three groups: symptomatic RT (n = 12; 29.3% female), asymptomatic RT (n = 38; 51.4% female), and asymptomatic untrained (n = 24; 57.1% female). Shoulder ROM and isometric strength were assessed using standardized procedures; functional performance was evaluated using the Closed Kinetic Chain Upper Extremity Stability Test and the modified Upper Quarter Y-Balance Test; postural characteristics were assessed using the acromion-to-wall distance and scapular dyskinesis evaluation. Results: males in the RT groups demonstrated greater normalized strength of the external rotators, abductors, and lower trapezius compared with untrained males, whereas fewer differences were observed among females (all p ≤ 0.035). Symptomatic and asymptomatic RT practitioners demonstrated largely similar outcomes across most variables. In contrast, RT practitioners demonstrated lower ROM, greater normalized muscle strength, superior performance in the CKCUEST, and greater normalized acromion-to-wall distance (all p ≤ 0.045). Furthermore, scapular dyskinesis during shoulder flexion differed between groups (p = 0.015). Females demonstrated greater ROM, whereas males exhibited greater values across multiple outcomes (all p ≤ 0.022). Conclusion: overall, shoulder characteristics differed more consistently according to training status and sex than according to shoulder symptom status. These findings may assist clinicians in interpreting shoulder assessments in RT practitioners.