This paper reviews physiological changes in the nervous system of patients with hemiparesis that may contribute to muscle weakness. The discussion includes the important role that alterations in the physiology of motor units, notably changes in firing rates and muscle fiber atrophy, play in the manifestation of muscle weakeness. This role is compared with the lesser role that spasticity of the antagonist muscle group appears to play in determining the weakness of agonist muscles. The contribution of other factors that result in mechanical restraint of the agonist by the antagonist is discussed relative to muscle weakness in patients with hemiparesis. More studies on patients with hemiparesis are required to assess what role muscle strength training should play in rehabiliting patients after a stroke.

Biofeedback devices have been used successfully to improve head control and symmetrical walking in cerebral palsied children. Biofeedback of postural sway was investigated as a therapeutic technique to reduce postural abnormality in 24 selected children with cerebral palsy. Subjects were evaluated their weight distribution of both sides during their standing before and after the visual and auditory feedback training. The effectiveness of biofeedback was compared to conventional physical therapy practices in reestabilishing symmetrical standing in cerebral palsied children. Our study found biofeedback was effective in training symmetrical standing posture.

An important characteristic of people with partially impaired walking ability, such as incomplete paraplegics, is that they are able to generate voluntary motion of lower-limbs. Therefore, wearable robots for the incomplete paraplegic patients require a different assistance method compared to those of complete paraplegics. First, the wearable robot should be controlled to not resist wearer’s motion. Second, it should be able to generate assistive torque accurately when needed. In this paper, a wearable robot, called EROWA, for the incomplete paraplegic patients is introduced. EROWA utilizes compact rotary series elastic actuators (cRSEAs) and a control method called the zero impedance control to reduce the mechanical resistance. An assistive torque trajectory is proposed to assist gait in this paper. The proposed method is verified by simulation and experimental studies.

Wearable robots are receiving great attention from the public, as well as researchers, because its motivation is to improve the quality of lives of people. Above all, complete paraplegic patients due to spinal cord injury (SCI) might be the most adequate target users of the wearable robots, because they definitely need physical assistance due to the complete loss of muscular strength and sensory functions. Furthermore, the medical care of complete paraplegics by using the wearable robots have significantly reduced the mortality rate and improved the life expectancy. The requirements of the wearable robot for complete paraplegics are actuation torque, locomotion speed, wearing sensation, robust gait stability, safety, and practicality (i.e., size, volume, weight, and energy efficiency). A WalkON Suit is the wearable robot that has satisfied the requirements of the wearable robot for complete paraplegics and participated in the powered exoskeleton race of Cybathlon 2016. In this paper, configuration of the WalkON Suit, human-machine interface, gait pattern, control algorithm, and evaluation results are introduced.