The overall aim of this thesis is to develop and assess novel electrical stimulation strategies in order to address the limitations of FES cycling in people with spinal cord injury (SCI), i.e. to postpone the onset of muscle fatigue and augment the power produced by the paralyzed muscles.
To assess the efficiency of electrical stimulation strategies, a novel instrumented cycling ergometer platform (ICEP) was developed. The capabilities of the platform were showcased by determining the stimulation patterns for reproducing the cycling movement in subjects with SCI.
An experimental study comparing the fatigue-reducing ability of spatially distributed sequential stimulation (SDSS) at high (HI) and moderate intensities (MI) in subjects with SCI was conducted. The results of this isometric study showed that MI SDSS is significantly more effective than HI SDSS when applied to the quadriceps muscle group.
A case study was performed on the ICEP to compare the power and fatigue produced while performing FES cycling using SDSS versus single electrode setup (SES). In two multiday sessions, paralyzed quadriceps muscles of 4 subjects were stimulated using MI while performing FES cycling with motor assistance. For each subject, SDSS produced more power than SES without a major influence on the fatigue level.
Finally, a prototype of a knee-angle-based FES cycling system using a stretch sensor was demonstrated to serve as a proof-of-concept for the development of simple and cheaper FES cycling equipment.
Contributions made in this work will make FES cycling a more effective rehabilitation tool available to a larger population.