Identifying shoulder and elbow passive moments and muscle contributions during static flexion-extension movements in the sagittal plane

The main goal of this study was an assessment of the shoulder and elbow joint passive moments in the sagittal plane. An industrial robot was used for moving a passive arm very slowly from extension to flexion and backwards. The motion was constrained to the sagittal plane, with a three degree of freedom planar structure assumed for the human arm. Comparing the obtained passive moments of six young male subjects showed a large adjacent angle dependency. Later on, voluntary muscle joint torques for one particular subject and trial were calculated, based on the acquired passive moment data. The presented methodology is aimed at an application on a rehabilitation robot.