WARD: a pneumatic system for body weight relief in gait rehabilitation.

The paper presents Walking Assistance and Rehabilitation Device (WARD), a system for walking rehabilitation devised to relieve the patient of his/her body weight of a constant and prescribed amount by externally supporting the subject at the upper trunk and pelvis level by means of a harness. The system is based on a pneumatic actuator that has proved to be effective at maintaining a constant relief force. The constancy of this force that should be maintained even under high body weight support (BWS) conditions (70-80% of body weight) seems to be important for a correct motor pattern. A law has been identified that may be useful to adjust walking speed as a function of the prescribed BWS. WARD is simple to construct, practical to use, and has been characterized on healthy subjects.