Comparison of the pedalling performance induced by magnetic and electrical stimulation cycle ergometry in able-bodied subjects

Abstract

The purpose of the study was to compare the mechanical power and work generated by able-bodied subjects during functional magnetic stimulation (FMS) vs. functional electrical stimulation (FES) induced ergometer training conditions. Both stimulation methods were applied at a 30Hz frequency to the quadriceps muscles of 22 healthy able-bodied subjects to induce cycling for 4× four minutes or until exhaustion. FMS was performed via large surface, cooled coils, while FES was applied with a typical stimulation setup used for cycling. Significantly more (p<10−3) muscular power was generated by FMS (23.8±9.1W [mean±SD]) than by FES (11.3±11.3W). Additionally, significantly more (p<10−6) work was produced by FMS than by FES (4.413±2.209kJ vs. 0.974±1.269kJ). The increase in the work was paralleled by a significant prolongation of time to cycling failure (181.8±33.4s vs. 87.0±54.0s, respectively, p<10−5). Compared to FES, FMS can produce more intense and longer cycling exercise in able-bodied subjects. The differing dynamic behaviour of FMS and FES in the presented measurement setup might be related to stimulation induced pain and fatigue mechanisms of the neuromuscular system.