This paper investigates the muscle activation of the upper arm for the progress monitoring of post-stroke rehabilitation. The performance measure is an indicator to monitor the progress of the rehabilitation exercise. The aim is for the fast recovery from the lost function of the upper limb as a result of the paralyzed patients. The investigation results will be employed in virtual reality (VR) game technology in the stroke rehabilitation exercise. It can solve the problem of the conventional stroke therapy which some prove inefficient and even some fail to regain patients' upper arm. The rehabilitation task requires the muscle activity measurement and monitoring of the progress that involve both fundamental and functional movements. By consistently do the rehabilitation exercise, patients can slowly develop the motor functions, which enables them to slowly regain the movement of the affected limb. In the experiments, five healthy subjects were selected. The experimental results show that deltoid has a significant activation compared with the bicep. In the VR systems, these two muscles will be used to monitor the progress of the rehabilitation.
