(Purpose) In order to quantitatively define the requirement of adequate protective synergy of the internal and external rotators, we evaluated isokinetic strength during concentric and eccentric activity, in normal shoulders and patients with anterior instability.
(Materials & Methods) 15 asymptomatic volunteers,12 patients with anterior instability were evaluated in this study. The isokinetic strength was measured in a standing position, with shoulder in abduction 45°, flextion 30°, using a KIN-COM dynamometer (Chattex Corpo. ).
(Results) 1)No patients had any shoulder pain or apprehension during the measurement.2)Eccentric and concentric activity ratios of the shoulder were about 1.2, lower than the other muscles, quandriceps, and the trunk muscles.3)In patients, not only internal rotators but also external rotators decreased during concentric and eccentric activity.
(Conclusion) These findings are useful when planning thee pre- and post- operative exercises for patients with anterior shoulder instability.
