Specific joint angle assessment of the shoulder rotators

Abstract

BACKGROUND: Independent peak torque (IPT) ratios may lead to misinterpretation of shoulder rotator imbalances. OBJECTIVE: To compare shoulder rotator IPT conventional ratio (CR) and dynamic control ratio (DCR) with ten-degree angle specific torque (AST) CR and DCR. METHODS: Twenty healthy adult males (24.65 ± 2.4 yrs) performed concentric (C) and eccentric (E) internal rotation (IR) and external rotation (ER) of the right shoulder on an isokinetic dynamometer at 60°/s and 180°/s through 150° of ROM. RESULTS: IPT DCR was significantly different than AST DCR at several angles at both test speeds. IPT CR were not significantly different than any AST CR at either speed. The last 3 ten degree AST DCR were also compared. AST DCR was significantly different at two angles at 60°/s and at three angles at 180°/s. CONCLUSION: DCR analysis should use a ten degree AST interpretative approach in order to avoid erroneous interpretations of shoulder rotator strength imbalances. IPT ratio tests should only be used to calculate CR.