The effects of electrode orientation on electromyographic amplitude and mean power frequency during cycle ergometry

Jorge M. Zuniga, Terry J. Housh, C. Russell Hendrix, Clayton L. Camic, Michelle Mielke, Richard J. Schmidt, Glen O. Johnson

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The purposes of this study were threefold: (1) to compare the power output related patterns of absolute and normalized EMG amplitude and MPF responses for electrode orientations that were approximately parallel and perpendicular to the muscle fibers of the vastus lateralis muscle (VL); (2) to examine the influence of electrode orientation on mean absolute EMG amplitude and MPF values; and (3) to determine the effects of normalization on mean EMG amplitude and MPF values from parallel and perpendicular electrode orientations. Twenty adults (10 men and 10 women mean ± SD age = 23.4 ± 3.6 years) performed incremental cycle ergometry tests to exhaustion. Two sets of bipolar surface EMG electrodes were placed approximately parallel and perpendicular to the muscle fibers over the VL. Paired t-tests indicated that absolute EMG amplitude values for the parallel electrode orientation were greater (p < 0.05) at 50, 75, and 100 W. The normalized EMG amplitude also had greater values for the parallel electrode orientation at 75 and 100 W. For absolute EMG MPF, the parallel electrode orientation had greater values for all six power outputs, but after normalization, the perpendicular electrode orientation had a greater value at 75 W. Ten percent of the subjects exhibited different power output related patterns of responses between electrode orientations for EMG amplitude and 35% exhibited different patterns for MPF. These findings indicated that normalization reduced, but did not eliminate the influence of electrode orientation and highlighted the importance of standardizing electrode orientation to compare EMG values during cycle ergometry.

Original languageEnglish (US)
Pages (from-to)256-262
Number of pages7
JournalJournal of Neuroscience Methods
Volume184
Issue number2
DOIs
Publication statusPublished - Nov 15 2009

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Keywords

  • Electromyography (EMG)
  • Parallel
  • Pedaling exercise
  • Perpendicular
  • SENIAM
  • Vastus lateralis

ASJC Scopus subject areas

  • Neuroscience(all)

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