Simulating an alternative FES induced fatigue in a recumbent cycling rehabilitation platform: limitations and perspectives

CAROLINA CHAVES-GARCIA; ESTEBAN OSELLA

Florianapolis

Congreso; IFMBE Proceedings Series - CLAIB CBEB 2022; 2022

In the lower limb rehabilitation and or restora-tion therapy research area, a particular strategy that has beinggrowing in the last decade is the combination of a recumbentbicycle where the pedals are driven using functional electricalstimulation (FES) over some of the patients’ muscles, and even-tually assisted by an electric motor linked to the pedals axle.Electric motors are generally used to provide support duringspecific crank regions, facilitating continuous pedaling and max-imizing treatment time, or to eventually assist the pedaling whenthe patients’ muscles get fatigued. Early fatigue is a well knownadverse effect of FES stimulation, which in many situations de-termines the reach and adherence of the patient to the therapyand possibly its indication by the therapist. In order to delayor mitigate the FES related early fatigue, it is required the de-sign of complex FES controllers. To fulfill this function, it is nec-essary to understand the behavior of fatigue depending on themuscle recovery capacity and the crankset load. In this paperwe present the impact of a fatigue model that considers bothrecovery phases (depending on the activation state) over a reha-bilitation therapy model commonly used in the literature. Theobtained results shows that the system reaches the desired ca-dence when the muscle is about to fully recover, if the load isgreater and the recovery less, the transient time of the motor isaffected to continue with effective pedaling