Talebian S, Bahrami Sh, Olyaei Gr, Bagheri H, Hadian Mr,
Volume 64, Issue 7 (9 2006)
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.
Talebian S, Olyaei Gr, Hadian Mr, Bagheri H, Mehrdad S,
Volume 65, Issue 4 (3 2007)
Abstract
Background: The changes in motor control after the use of a supportive belt can contribute to the understanding of its effects on performance. The aim of this study is to quantify motion pattern values relative to the spinal column during the use of a lumbosacral belt.
Methods: For fifty healthy female volunteers, the range of motion, maximum isometric torque and changes of phase angle of maximum torque and velocity in two positions, standing and sitting, in two directions, flexion and extension, following the use of a lumbosacral belt were measured using an isoinertial dynamometer (Isostation B200) and compared.
Results: Range of motion in both directions in both positions was reduced significantly (P<0.05). Significant reduction of maximum isometric torque was observed in flexion while sitting and in extension while standing and sitting (P<0.05). Phase angle of maximum torque and velocity also changed significantly in both directions and both positions (P<0.05).
Conclusion: The lumbosacral belt can act in different ways to prevent injury. It reduces the forces applied to lumbar vertebra and, by changing the maximum torque and velocity phase angles at the onset of range of motion, provides greater stability for joints. Furthermore, the belt can reduce stress imposed on the posterior joints of the spine and limits several momentary forces at the onset of joint movement. Under these conditions, joint injuries can be reduced and prevent some of the mechanical stress that causes lumbar joint disease.
