High-performance swimming is a highly physically demanding sport that requires thousands of shoulder rotations per training session and specific positions of the shoulder. This group of athletes undergoes a set of adaptive biomechanical changes that include increased internal rotation range, increased anterior joint laxity, posterior joint capsule stiffness and internal rotation deficit (GIRD). The use of the internal rotator muscles as propulsors favours an imbalance between the internal and external rotators of the shoulder complex, with an advantage for the former. The multiplicity of changes appears to contribute to anterior translation of the humeral head, with a consequent increase in the risk of anterior impingement. These injuries, which result from impact and/or compression involving different joint components, occur primarily in positions where the humerus is in internal rotation. The most common is subacromial impingement.

 

Methods:
The aim of this observational study was to determine whether it is possible to predict the risk of developing anterior impingement through a ‘simple’ physical examination. We sought to determine whether the development of biomechanical changes in swimmers with anterior pain – GIRD, changes in TROM and/or the strength ratio between IR and ER – translates into symptoms or signs on physical examination. We assessed the frequency of anterior pain, specific clinical tests of the shoulder complex, the range of active IR and RE, and the strength of the respective muscle groups, to establish analytical correlations between clinical characteristics and biomechanical parameters.

 

Results:
Although we did not establish any relationship between increased pain frequency and biomechanical adaptations, we found a statistically significant association between a positive result in the clinical tests and an increased ratio of IR/ER strength, which may indicate an imbalance between these muscle groups. 

 

Discussion:
The results suggest that positive clinical test findings may be associated with an increased IR/ER ratio and, possibly, with the development of muscle changes that predispose to anterior impingement. We therefore recommend periodic physical examinations for elite swimmers, including assessment of positive clinical shoulder tests, in order to anticipate the potential risk of injury to the anterior compartment of the glenohumeral joint.

 

Keywords:
athletes, shoulder pain, shoulder rotator cuff strength, impingement shoulder injury, swimming, strength ratio, external rotation of the shoulder, internal rotation of the shoulder.