The aim of the work was to analýze the muscle dysfunction from the viewpoint of laterality in the respect to the muscle unbalance at 69 „right nand" tennis players (35 boys, 34 girls), and to observe in the 7-month interval of experiment its impact by the compensation exercises and specific game exercises. The functional disorders recorded in the majority of examined pair muscles the sings of lateral asymmetry with the right-side prevalence. The results of 7-months experiment showed statistically significant improvement of muscle function in all indicators, the reducing the lateral difference, in some parameters even the lateral symmetry. After omission of compensation exercises we recorded at the final examination the retům to the originál values.

        Key words: kinetic system, asymmetry of functional muscle disorders, young tennis players