An analysis of the combined effects of swimming and overhead throwing on the shoulder complexes of male first division waterpolo players
Authors:   , Conor Beckett Gibb 
Published: June 2022

Background Abstract Waterpolo is often compared to other sports, mainly swimming and overhead throwing sports. Swimming favours a posture of glenohumeral internal rotation and horizontal adduction. Overhead throwing sports can characteristically cause posterior shoulder immobility with a loss in glenohumeral internal rotation and horizontal adduction. Based on the fact that waterpolo players combine both swimming and overhead throwing whilst playing and training, it is the purpose of this study to investigate the sport-specific characteristics of the shoulder complexes of waterpolo players in an effort to determine how these unique characteristics may relate to the development of overuse injuries. Aim The aim of this study is to compare the dominant and non-dominant shoulder complexes of male water polo players in terms of posture, range of motion and sport- specific overuse injuries in order to develop an understanding of the combined effects of swimming and overhead throwing on the shoulders of water polo players. Methods The study used an observational based research design and consisted of 33 male waterpolo players currently competing in the Kwa-Zulu Natal mens 1st division waterpolo league. Participants underwent a shoulder digital posture examination as well as a shoulder-complex physical examination consisting of range of motion and orthopaedic testing which was then compared between the dominant and non- dominant shoulders. Participants were assessed for the presence of rotator cuff injury, glenoid labrum and LHBT injury, and anterior glenohumeral instability using the following physical tests: Empty can test, painful arc test, external rotation resistance, Hawkins-Kennedy test, Neer test, Yergassons test, Biceps Load test II, and the apprehension-relocation-surprise test. Glenohumeral range of motion was assessed using manual goniometry to measure passive internal and external rotation and horizontal adduction. Statistical analysis was performed using IBM SPSS version 27 statistical analysis software. Paired tests were used to compare outcomes from the dominant and non-dominant shoulders of the participants. To compare the posture measurements, as well as injuries present between the dominant and non-dominant shoulders, McNemar’s chi square tests were used. To compare the Range of motion measurements between the dominant and non-dominant shoulders, paired t-tests were used. A p value < 0.05 was considered statistically significant. Results Forward head posture with rounded shoulders was extremely common, with 73% of the participants in this study displaying a bilateral forward shoulder position ranging from moderate to severe, and 45% of participants displaying a bilateral forward head posture ranging from mild to severe. Glenohumeral internal and external rotation ROM measurements showed no difference between sides. There was a borderline significant difference (p=0.05) in the horizontal adduction measurements, with the non- dominant side showing greater values. The only injury test that yielded significant results was the empty can test for supraspinatus injury that had a higher prevalence for being positive on the dominant side. Conclusion The results of this study suggest that water polo players are prone to the development of a bilaterally equal forward head posture with rounded shoulders and are susceptible to similar mechanisms of bilateral overuse injury as swimmers. In addition, the dominant shoulders of these athletes are susceptible to damage caused by the repetitive, traumatic forces experienced by the posterior cuff musculature and posterior glenohumeral joint capsuloligamentous structures during the follow-through and deceleration phases of overhead throwing, resulting in an increased risk of supraspinatus-specific rotator cuff injury and a loss of glenohumeral horizontal adduction that potentially increases the risk of glenoid labrum and LHBT injury.