Alternating stimulation of synergistic muscles during functional electrical stimulation cycling improves endurance in persons with spinal cord injury

摘要

Therapeutic effects of functional electrical stimulation (FES) cycling for persons with spinal cord injury (SCI) are limited by high rates of muscular fatigue. FES-cycling performance limits and surface mechanomyography (MMG) of 12 persons with SCI were compared under two different stimulation protocols of the quadriceps muscles. One strategy used the standard " co-activation" protocol from the manufacturer of the FES cycle which involved intermittent simultaneous activation of the entire quadriceps muscle group for 400. ms. The other strategy was an " alternation" stimulation protocol which involved alternately stimulating the rectus femoris (RF) muscle for 100. ms and the vastus medialis (VM) and vastus lateralis (VL) muscles for 100. ms, with two sets with a 400. ms burst. Thus, during the alternation protocol, each of the muscle groups rested for two 100. ms " off" periods in each 400. ms burst. There was no difference in average cycling cadence (28. RPM) between the two protocols. The alternation stimulation protocol produced longer ride times and longer virtual distances traveled and used lower stimulation intensity levels with no differences in average MMG amplitudes compared to the co-activation protocol. These results demonstrate that FES-cycling performance can be enhanced by a synergistic muscle alternation stimulation strategy.