Comparison of proximally versus distally placed spatially distributed sequential stimulation electrodes in a dynamic knee extension task

  • Marco Laubacher | marco.laubacher@bfh.ch Institute for Rehabilitation and Performance Technology, Bern University of Applied Sciences, Burgdorf; Sensory Motor Systems Lab, ETH Zurich, Zürich, Switzerland.
  • Efe A. Aksöz Institute for Rehabilitation and Performance Technology, Bern University of Applied Sciences, Burgdorf; Sensory Motor Systems Lab, ETH Zurich, Zürich, Switzerland.
  • Stuart Binder-Macleod Department of Physical Therapy, University of Delaware, Newark, United States.
  • Kenneth J. Hunt Institute for Rehabilitation and Performance Technology, Bern University of Applied Sciences, Burgdorf, Switzerland.

Abstract

Spatially distributed sequential stimulation (SDSS) has demonstrated substantial power output and fatigue benefits compared to single electrode stimulation (SES) in the application of functional electrical stimulation (FES). This asymmetric electrode setup brings new possibilities but also new questions since precise placement of the electrodes is one critical factor for good muscle activation. The aim of this study was to compare the power output, fatigue and activation properties of proximally versus distally placed SDSS electrodes in an isokinetic knee extension task simulating knee movement during recumbent cycling. M. vastus lateralis and medialis of seven able-bodied subjects were stimulated with rectangular bi-phasic pulses of constant amplitude of 40 mA and at an SDSS frequency of 35 Hz for 6 min on both legs with both setups (i.e. n=14). Torque was measured during knee-extension movement by a dynamometer at an angular velocity of 110 deg/s. Mean power, peak power and activation time were calculated and compared for the initial and final stimulation phases, together with an overall fatigue index. Power output values (Pmean, Ppeak) were scaled to a standardised reference input pulse width of 100 μs (Pmean,s, Ppeak,s). The initial evaluation phase showed no significant differences between the two setups for all outcome measures. Ppeak and Ppeak,s were both significantly higher in the final phase for the distal setup (25.4 ± 8.1 W vs. 28.2 ± 6.2 W, p=0.0062 and 34.8 ± 9.5 W vs. 38.9 ± 6.7 W, p=0.021, respectively). With distal SDSS, there was modest evidence of higher Pmean and Pmean,s (p=0.071, p=0.14, respectively) but of longer activation time (p=0.096). The rate of fatigue was similar for both setups. For practical FES applications, distal placement of the SDSS electrodes is preferable.

Dimensions

Altmetric

PlumX Metrics

Downloads

Download data is not yet available.
Published
2016-06-13
Info
Issue
Section
2016 IFESS Conference
Keywords:
Functional electrical stimulation, Spatially distributed sequential stimulation, Knee dynamometer, Fes cycling
Statistics
  • Abstract views: 1029

  • PDF: 455
  • HTML: 394
How to Cite
Laubacher, M., Aksöz, E., Binder-Macleod, S., & Hunt, K. (2016). Comparison of proximally versus distally placed spatially distributed sequential stimulation electrodes in a dynamic knee extension task. European Journal of Translational Myology, 26(2). https://doi.org/10.4081/ejtm.2016.6016

Most read articles by the same author(s)