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Updated: Jul 16, 2026
Paradigms of Lower Extremity Electrical Stimulation Training After Spinal Cord Injury
Published on: February 1, 2018
Low-frequency rectangular pulse is superior to middle frequency alternating current stimulation in cycling of people
Johann Szecsi1, Ché Fornusek, Phillip Krause
1Center for Sensorimotor Research, Department of Neurology, Ludwig-Maximillians University, Munich, Germany. jszecsi@nefo.uni-muenchen.de
Objective:
To determine the efficacy of using modulated middle frequency alternating current (MFAC) muscle stimulation for functional electric stimulation-propelled cycling by people with spinal cord injury (SCI) compared with the conventional method of using standard low-frequency rectangular pulses (LFRP).
Design:
Repeated-measures.
Setting:
Laboratory setting.
Participants:
Eleven otherwise healthy volunteer subjects with SCI (8 with American Spinal Injury Association [ASIA] grade A, 3 with ASIA grade B).
Interventions:
To evaluate cycling-relevant differences between LFRP and modulated MFAC stimulation, we exposed participants to isometric measurements and cycling experiments performed during both 20 Hz LFRP and 4 KHz modulated with 50 Hz MFAC.
Main Outcome Measures:
We recorded maximal isometric torque, maximal dynamic work during 20 minutes of ergometer cycling, and perceived discomfort for each of the 2 stimulation patterns.
Results:
Both the isometric torque (P<.02) and work generated (P<.001) during MFAC stimulation were significantly lower than during standard LFRP stimulation. Four participants reported discomfort and 1 of them also developed skin burns during MFAC stimulation.
Conclusions:
Our findings suggest that in SCI subjects, stimulated cycling with low frequency is generally more effective than cycling with modulated MFAC in terms of torque, work, and pain sensation.
