Repetitive sport activities over many years cause specific muscular adaptations. Sport-specific changes are expressed among other things in the strength profile of the performance-linked joints. The shoulder muscles, and particularly the rotator cuff muscles play a basic role in tennis. The strength profile of agonist and antagonist muscles of the rotator cuff in shoulder-healthy tennis players can deliver important information in regard to sport-specific rehabilitation. The goal of this study was to set up a triple-component strength ratio of the rotator cuff muscles for high performance tennis players and to compare it with the values in non-specifically training physical education students. The triple-component strength ratio is defined as eccentric external rotation strength : concentric internal rotation strength : concentric external rotation strength (EAR : KIR : KAR). Concentric and functional strength ratios arc, summarized in this strength ratio. Isokinetic shoulder rotational strength (Cybex Norm) was evaluated in two groups of subjects as follows: 10 tennis players, and 10 non-specifically trained physical education students. Peak torque values were determined at 60degrees/s and 300degrees/s for the dominant shoulder.