title: The influence of electromyographic recording methods and the innervation zone on the mean power frequency-torque relationships.
abstract: This study examined the effects of electromyographic (EMG) recording methods and innervation zone (IZ) on the mean power frequency (MPF)-torque relationships. Nine subjects performed isometric ramp muscle actions of the leg extensors from 5% to 100% of maximal voluntary contraction with an eight channel linear electrode array over the IZ of the vastus lateralis. The slopes were calculated from the log-transformed monopolar and bipolar EMG MPF-torque relationships for each channel and subject and 95% confidence intervals (CI) were constructed around the slopes for each relationship and the composite of the slopes. Twenty-two to 55% of the subjects exhibited 95% CIs that did not include a slope of zero for the monopolar EMG MPF-torque relationships while 25-75% of the subjects exhibited 95% CIs that did not include a slope of zero for the bipolar EMG MPF-torque relationships. The composite of the slopes from the EMG MPF-torque relationships were not significantly different from zero for any method or channel, however, the method and IZ location slightly influenced the number of significant slopes on a subject-by-subject basis. The log-transform model indicated that EMG MPF-torque patterns were nonlinear regardless of recording method or distance from the IZ.
authors: Department of Health, Sport, and Exercise Sciences, Neuromechanics Laboratory, University of Kansas, Lawrence, KS, USA. Electronic address: t.herda@ku.edu.
authors: Trent J
authors: TJ
authors: Herda
authors: Exercise Science Department, Creighton University, Omaha, NE, USA.
authors: Jorge M
authors: JM
authors: Zuniga
authors: Department of Exercise and Sport Science, Neuromuscular Research Laboratory, University of North Carolina - Chapel Hill, Chapel Hill, NC, USA.
authors: Eric D
authors: ED
authors: Ryan
authors: Exercise and Sport Science Department, University of Wisconsin-La Crosse, La Crosse, WI, USA.
authors: Clayton L
authors: CL
authors: Camic
authors: Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA.
authors: Haley C
authors: HC
authors: Bergstrom
authors: Department of Health and Human Performance, Oklahoma State University, Stillwater, OK, USA.
authors: Doug B
authors: DB
authors: Smith
authors: Department of Health, Sport, and Exercise Sciences, Neuromechanics Laboratory, University of Kansas, Lawrence, KS, USA.
authors: Joseph P
authors: JP
authors: Weir
authors: Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA.
authors: Joel T
authors: JT
authors: Cramer
authors: Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA.
authors: Terry J
authors: TJ
authors: Housh
mesh_terms: D000328:Adult; D004566:Electrodes; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D052097:Quadriceps Muscle / Q000294:innervation* / Q000502:physiology*; D019415:Torque; D055815:Young Adult
keywords: Bipolar; EMG; Linear array; MPF; Monopolar