Tehran University Medical Journal (Aug 2006)
Comparison of concentric isokinetic dominant shoulder internal and external rotator torque between professional female volleyball and tennis players
Abstract
Background: The purpose of this study was to measure isokinetic maximum and average peak torque of internal and external rotators of glenohumeral joint in volley ball and tennis players Methods: This study was performed on 17 professional female athletes (7 tennis players &10 volleyball players) with age ranged 18-28 years. The subjects had played in a skilled team for more than 3 years. They were free from injury to their dominant shoulder in the past year. Subjects performed a five minute warm up by shoulder wheel and Maximum average Peak Torque (APT) were obtained unilaterally by a Biodex System 3 with the arm of players in 90 degree abduction at 120,180 & 210 o/s. Players performed five trails of concentric movements with 30 second rest between them. Results: Maximum and average of maximum torques of shoulder rotator, in both groups, expect for internal rotators of tennis players, reduced by increase of movement speed (P<0.05). There are not significant difference between two groups in maximum, average of maximum torques and normalized data (ratio of maximum torque to weight). There is significant difference between two groups in percentage of APT of External rotator / Internal rotator ratio at 210 o/s (P<0.05). Conclusion: Volleyball and tennis have no effect on isokinetic strength of shoulder rotators. In high speed, ratio of External rotator / Internal rotator is reduced. This indicates that increase in movement speed increase internal rotator in comparison to external rotator in these professional female athletes.
