INTRODUCTION: Swimming is an extremely demanding physical activity, celebrated for its cardiovascular benefits and general improvement of physical well-being. However, the repetitive nature of swimming motions can place significant stress on the swimmer's musculoskeletal structures, particularly in the shoulder joint. Studies suggest that as many as 70% of competitive swimmers experience shoulder pain during their careers. The aim of this research was to examine how shoulder strengthening exercises in competitive swimmers affect the reduction of shoulder pain and to examine whether increasing the strength of the shoulder muscles will reduce overload in the shoulder girdle. SUBJECTS AND METHODS: A total of 45 male and female swimmers between the ages of 14 and 25 participated in this study. Each of the swimmers in the last year felt pain in the shoulder while swimming. Respondents were reached through swimming clubs in Zagreb. Each of the swimmers completed a shoulder pain questionnaire from TheOsloSportsTraumaResearchCenter (OSTRC). Also, the external rotation strength of the swimmers was measured using the EasyForce electric dynamometer. RESULTS: Based on the data collected from 45 subjects, it can be said that exercises to strengthen the external rotators affect the reduction of pain in swimmers with rotator cuff injuries. Exercise has been proven to strengthen muscles, which results in a reduction in pain over time. Furthermore, no statistically significant difference was observed between the "OSTRC QUESTIONNAIRE SCORES" group and the "muscle force L" (p = 0.142). Also, no statistically significant difference was observed between the "OSTRC QUESTIONNAIRE SCORES" group and "muscle force D" (p = 0.123). DISCUSSION AND CONCLUSION: The analysis of the obtained results determined that exercises to strengthen the external rotators affect the reduction of pain in swimmers with rotator cuff injuries. Therefore, hypothesis number 1 is accepted. Conversely, the second hypothesis, which states that increasing shoulder muscle strength will lead to a reduction in shoulder muscle overload, was not confirmed. Therefore, hypothesis number 2 is rejected. KEYWORDS: muscle strength, swimmer, shoulder, shoulder exercises.