Automatic Finite State Control of FES-Assisted Indoor Rowing Exercise after Spinal Cord Injury

Abstract

We modified a commercial indoor rowing machine (Concept 2 Inc., Morrisville, NJ, USA) for a functional electrical stimulation (FES) assisted indoor rowing exercise in which the rowers must repeatedly press the two switches on the handle that stimulate their paralyzed leg muscles. The objective of this study was to automate the delivery of electrical stimulation to prevent potential repetitive strain injuries and to expand the user base to clients with impaired hand function. The modifications for development of the FES rowing machine and clinical trials were all performed in the University of Alberta. A new controller was developed to automatically control the electrical stimulation of the paralyzed leg muscles to perform the lower extremity part of the rowing maneuver while the subject voluntarily performed the upper body part of the maneuver. Two paraplegic users of the older manual control system tested the new automatic controller. The automatic FES controller spent more electrical stimulation per rowing cycle but it did not require repetitive thumb presses, required less concentration, and was preferred by the clients. We conclude FES rowing with the new automatic controller was easier and safer and expanded the user base of the FES rowing exercise to those with affected hand.