CONCENTRIC AND ECCENTRIC ISOKINETIC STRENGTH PROFILE OF SHOULDER ROTATORS IN ELITE JUNIOR TENNIS PLAYERS

Abstract

The purpose of this study was to evaluate concentric (con) and eccentric (ecc) isokinetic strength of shoulder rotators in elite junior tennis players. Shoulder rotator strength was measured bilaterally in 40 junior tennis players (26 male and 14 female) at 60 and 180°/s. Dominant internal rotation (IR) strength development was found for both sexes. Boys also had a dominance effect in the external rotators (ER) in both modes. This discrepancy between sexes also was evident in the unilateral strength ratio (ERcon/IRcon), with girls within the normal range and boys at a recommend level. In both sexes, the functional ratios (ERecc/IRcon) were lower than the ideal to prevent joint overloading. Exercises involving concentric and eccentric strengthening of external rotators are necessary to restore shoulder imbalances, especially for females tennis players.