The influence of electrode orientation on the electromyographic amplitude and mean power frequency versus isometric torque relationships for the vastus lateralis

Clayton Camic, Terry Housh, Jorge Zuniga, Russell Hendrix, Michelle Mielke, Glen Johnson, Richard Schmidt

Research output: Contribution to journalArticle

Abstract

Camic CL, Housh TJ, Zuniga JM, Hendrix CR, Mielke M, Johnson GO, Schmidt RJ. The Influence of Electrode Orientation on the Electromyographic Amplitude and Mean Power Frequency Versus Isometric Torque Relationships for the Vastus Lateralis. JEPonline 2010;13(1):10-20. The purposes of this study were to compare parallel versus perpendicular electrode orientations during isometric muscle actions for: 1) the torque-related patterns of responses for electromyographic (EMG) amplitude and mean power frequency (MPF); 2) the mean absolute EMG amplitude and MPF values; and 3) the mean normalized EMG amplitude and MPF values. Eleven adults (mean ± SD age = 23.9 ± 3.0) performed isometric muscle actions at 10 - 100% MVC on a Cybex II dynamometer. Two bipolar EMG electrode arrangements were placed approximately parallel and perpendicular to the muscle fibers over the vastus lateralis. Twenty-seven percent of the subjects exhibited different torque-related patterns of responses between electrode orientations for EMG amplitude and 55% exhibited different patterns for MPF. The mean absolute EMG amplitude and MPF values were greater for the parallel than the perpendicular electrode orientation for 10 and 9 of the torque levels, respectively. For the normalized EMG amplitude and MPF values, however, the parallel electrode orientation was greater than the perpendicular for only 2 and 1 torque level, respectively. These findings indicated that normalization reduced, but did not eliminate, the influence of electrode orientation and emphasized the importance of standardizing electrode orientation to compare EMG values.

Original languageEnglish (US)
Pages (from-to)10-20
Number of pages11
JournalJournal of Exercise Physiology Online
Volume13
Issue number1
StatePublished - Feb 2010

Keywords

  • Normalization
  • Parallel
  • Perpendicular

ASJC Scopus subject areas

  • Physiology (medical)

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