A comparison of torque production during dynamic strength testing of shoulder abduction in the coronal plane and the plane of the scapula.

Abstract

Quantitative measurement of the shoulder abductors is important in a comprehensive assessment of shoulder muscle performance. Testing in traditionally accepted positions may be compromising to the glenohumeral static and dynamic stabilizers; therefore, there is a need to investigate testing in other planes of motion. The purpose of this study was to compare torque produced during isokinetic testing of shoulder abduction in the coronal plane and the scapular plane. Twenty female subjects with no previous shoulder pathology were tested at 90 degrees/sec and 210 degrees/sec in the coronal and scapular planes using the Cybex II isokinetic dynamometer. Both peak torque and mean peak torque of three trials were recorded. A t test for related samples (p < .05) revealed no significant difference in the peak and mean peak torque produced at each speed. Using a two-way analysis of variance with repeated measures, no significant difference was found in the peak torque produced between the two planes. However, torque production at 90 degrees/sec in both test positions was significantly higher than torque production at 210 degrees/sec (F1,19 = 159.610, p < .001). Although anatomical, functional, and clinical reasons have been proposed for performing exercise and testing procedures of the shoulder abductors in the scapular plane, the results of this study indicate that in healthy young women, there is no difference in torque production between the two planes.