Table of Contents
Journal of Medical Engineering
Volume 2016 (2016), Article ID 6957287, 12 pages
Research Article

Potential of M-Wave Elicited by Double Pulse for Muscle Fatigue Evaluation in Intermittent Muscle Activation by Functional Electrical Stimulation for Motor Rehabilitation

1TESS Co., Ltd., T-Biz 404, 6-6-40 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8579, Japan
2Graduate School of Biomedical Engineering, Tohoku University, 6-6-12 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8579, Japan

Received 16 July 2015; Revised 7 November 2015; Accepted 28 February 2016

Academic Editor: Sridhar Krishnan

Copyright © 2016 Naoto Miura and Takashi Watanabe. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Clinical studies on application of functional electrical stimulation (FES) to motor rehabilitation have been increasing. However, muscle fatigue appears early in the course of repetitive movement production training by FES. Although M-wave variables were suggested to be reliable indices of muscle fatigue in long lasting constant electrical stimulation under the isometric condition, the ability of M-wave needs more studies under intermittent stimulation condition, because the intervals between electrical stimulations help recovery of muscle activation level. In this paper, M-waves elicited by double pulses were examined in muscle fatigue evaluation during repetitive movements considering rehabilitation training with surface electrical stimulation. M-waves were measured under the two conditions of repetitive stimulation: knee extension force production under the isometric condition and the dynamic movement condition by knee joint angle control. Amplitude of M-wave elicited by the 2nd pulse of a double pulse decreased during muscle fatigue in both measurement conditions, while the change in M-waves elicited by single pulses in a stimulation burst was not relevant to muscle fatigue in repeated activation with stimulation interval of 1 s. Fatigue index obtained from M-waves elicited by 2nd pulses was suggested to provide good estimation of muscle fatigue during repetitive movements with FES.