Isokinetic strength of the shoulder rotators in primary school boys

Twenty boys aged between eight and 12 years were studied to determine the reliability of using an isokinetic dynamometer (KIN-COM) in evaluating shoulder rotation and to assess the relationship of anthropometric measures to isokinetic strength. Using a repeated measures design, each subject was asked to work the internal and external rotators of the glenohumeral joint of the dominant upper extremity concentrically and eccentrically at two speeds in random order on two separate occasions. Results showed no significant differences between the strength data collected on the two occasions. Internal rotators were found to be significantly stronger than the external rotators and the eccentric strength was significantly greater than the concentric strength. A significant relationship between the anthropometric measures (age, height and lean body weight) and the isokinetic strength was also demonstrated.