Introduction: The shoulder joint is the most mobile, but at the same time the most unstable joint in the human body. In addition to passive stabilizers, active stabilizers, especially the rotator cuff muscles, are crucial for the stability of the shoulder joint. Their performance is assessed by isokinetic dynamometry, which is a reliable and valid instrument for muscle testing and is often used as a reference standard for testing muscle performance in athletes with a typical overhead arm movement, i.e. all those who regularly move their arm during sports activity above the head and thus the shoulder joint and ring in more than 90 degrees of elevation, typically e.g. in handball, cricket and volleyball. Purpose: The purpose of the thesis was to analyze asymmetries in muscle capacity of the shoulder joint rotators in healthy athletes with characteristic overhead arm movement, through a literature review. Methods: The literature search was conducted in the PubMed and CINAHL Ultimate databases. We used different keywords and their combinations in the English language: strength asymmetry, volleyball athletes, isokinetic dynamometry and male handball athletes. Research in English, with freely available text, no older than 15 years and dealing with athletes with a characteristic overhead arm movement was included. Results: We included five studies in the detailed literature review. Despite different testing protocols, research results show that the internal rotators on the dominant upper limb are stronger than the external rotators on the same limb, and most authors also reported a higher concentric ratio between the external and internal rotators on the non-dominant upper limb at angular velocities: 60° /s, 180°/s, 300°/s. Research results have also shown that male handball players have more powerful shoulder rotators than athletes of other disciplines. Discussion and Conclusion: The results of the reviewed research showed that the capacity of the external and internal rotators of the shoulder is greater on the dominant limb, but the functional ratio of their maximum torques is better on the non-dominant limb. In future research, it would be necessary to standardize the testing protocols and the measuring device for more valid and reliable results.
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