Mechanomyographic and electromyographic responses of the
superficial muscles of the quadriceps femoris during maximal, concentric
isokinetic muscle actions
Affiliations: [a] Department of Health and Human Performance, University
of Nebraska-Lincoln, Lincoln, NE 68588-0229, USA | [b] Department of Human Kinetics, University of
Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
Note: [] Department of Health and Human Performance, University of
Nebraska-Lincoln, MABL 136, Lincoln, NE 68588-0229, USA. Tel.: +1 402 472 2571,
ext. 2; Fax: +1 402 472 4305; E-mail: jcramer@unlserve.unl.edu
Abstract: Eleven adult males (mean \pm SD age = 22
\pm 3 years) performed maximal, concentric isokinetic leg extension
muscle actions at velocities of 60, 120, 180, 240, and
300^{\circ}\cdots^{-1} on a Cybex 6000
dynamometer. The results indicated that peak torque (PT) decreased
(p<0.05) as muscle action velocity increased.
Mechanomyographic (MMG) amplitude increased with velocity to
180^{\circ}\cdots^{-1} for each muscle
tested (vastus lateralis = VL, rectus femoris
= RF, and vastus medialis = VM). For the
VL, MMG amplitude continued to increase to
240^{\circ}\cdots^{-1} and then
plateaued, while the RF plateaued from 180 to
300^{\circ}\cdots^{-1}. The VM showed a
constant increase in MMG amplitude to
300^{\circ}\cdots^{-1}. Electromyographic
(EMG) amplitude increased to
180^{\circ}\cdots^{-1} and then plateaued
for each muscle. These findings indicated muscle-specific differences in MMG
amplitude patterns across velocity that may be attributable to differences in
fiber type composition, muscle architecture, and/or tissue layer composition.
Furthermore, these results suggested that there were muscle-specific,
velocity-related differences in the association between motor unit activation
(EMG) and the mechanical aspects of muscular activity (MMG).
