A functional electrical stimulation system for moving at least a portion of a body of a subject, e.g., legs. Such a system includes: a stimulator that can provide a plurality of sets of functional electrical stimulation to the legs, one or more transducers that outputs signals representative of the movement made by the legs in response to the functional electrical stimulation provided thereto, and a controller. The controller compares the output signals of the transducers resulting from the provision of two or more substantially equivalent sets of electrical stimulation to the legs and provide an output indicative of variation in the movement. The controller also, e.g., can compare the level of electrical stimulation output by the stimulator to achieve an equivalent movement of the legs so as to recognize an increase in such stimulation, where an increase can be indicative of fatigue in the leg muscles.
