A functional electrical stimulation brace responsive to various positions of an intended wearer's foot. The device includes a plurality of sensors positioned at different locations under the intended wearer's foot to detect the current position of the foot. Outputs from the sensors are fed to a controller that uses logic to activate an electrical stimulation unit that stimulates the peroneal muscles of a patient at the appropriate times during the patient's gait. The device may also employ mechanical stabilization of the ankle in addition to the functional electrical stimulation by means of an ankle foot orthosis with a variable resistance hinge. The electrodes are embedded in fixed locations in the brace upper portion so that optimal location of the electrodes relative to the peroneal muscles is maintained every time the device is applied. Also provided is a method for assistance and rehabilitation for a patient by electrical stimulation of the peroneal muscles. In the method, the position of the foot is detected and the peroneal muscles are stimulated responsive to particular positions of the patient's foot in order to activate the muscles at the appropriate times during the patient's gait. The device also provides lateral and torsional stability by means of the ankle-foot orthosis.