A sensorized FES-cycling system to quantify training performance and optimize stimulation strategies

For people with a spinal cord injury (SCI), cycling by means of Functional Electrical Stimulation (FES) represents an effective rehabilitation exercise. FES-cycling can have beneficial effects on paretic muscles reducing the secondary effects caused by paralysis. Moreover, it can be seen as a way to perform an inclusive sport activity for people with disability, making it an example of “Sport-Therapy”. In recent years, the Cybathlon competition has renewed the interest in this discipline. This paper presents the set-up of a mobile FES-cycling system. A commercial passive recumbent trike has been adapted for the use of cyclists with SCI. Two four-channel stimulators have been integrated in the system together with a measurement chain. This latter is composed by an encoder, a heart rate sensor and sensorized pedals to measure tangential and radial forces that the subject is producing with each leg independently. The system is developed with the aim to give real-time outcome information about cycling performance and to quantify differences between several stimulation strategies. One SCI pilot was involved in the study and exemplary results acquired during one of his training sessions are shown to demonstrate the feasibility of the system and its potentiality. In future, this set-up could be used to optimize stimulation strategies.