A model-based identification procedure of stimulation angular ranges for FES-cycling

FES-cycling is a leading example of “Sport Therapy,” a rehabilitation technique that combines the therapeutical benefits of Functional Electrical Stimulation (FES) with the psychological advantages of physical activities in people with disabilities. Considering cycling by means of FES, given the poor power output and the early onset of muscular fatigue in stimulated muscles and rough outdoor surfaces, an optimization of cycling efficiency must be carried out. Different parameters of FES may be adjusted to increase the exercise performances; one is represented by the angular ranges in which each muscle must be stimulated. In this article, we present an identification procedure based on a biomechanical model to automatically compute the stimulation angular ranges. A comparison between the model-based ranges and the electromyographic (EMG) activation intervals of the able-bodied subject was carried out. Moreover, one SCI subject was involved in a testing session to verify the consistency and applicability of the ranges on a recumbent trike. Results showed that the model-based intervals were in agreement with physiological muscular activations, and the pilot was able to fully perform the cycling exercise.