Affiliations: [a] University of Nebraska-Lincoln, Lincoln, NE 68588,
USA | [b] Wayne State College, Wayne, NE 68787, USA | [c] University of Missouri-Kansas City, Kansas City, MO
64110, USA
Note: [] University of Wisconsin-Milwaukee, Department of Human Kinetics,
Athletic Training Research Laboratory, P.O. Box 413, Milwaukee, WI 53211, USA.
Tel.: +1 414 229 5553; Fax: +1 414 906 3973; E-mail: ebersole@uwm.edu
Abstract: The purpose of this investigation was to examine the
mechanomyographic (MMG) responses to maximal concentric (CON) and passive leg
extension movements. Eight adult females performed maximal CON muscle actions
and passive leg extension movements of the dominant leg on a calibrated CYBEX
6000 dynamometer at velocities of 30, 90, and
150^{\circ}\cdots^{-1}. MMG and
electromyographic (EMG) signals were simultaneously recorded from the vastus
lateralis (VL). The results indicated velocity-related dissociations among MMG
amplitude, EMG amplitude, and peak torque during the maximal CON muscle
actions. For the passive leg extension movements, however, the EMG amplitude
values at each velocity were not significantly (p > 0.05)
different from the values at rest, but the MMG amplitude increased
significantly (p < 0.05) with velocity. It was hypothesized
that the velocity-related increase in MMG amplitude for the passive leg
extension movements was independent of VL activation and may have been
associated with turbulences of the intracellular and extracellular fluid
mediums and/or cross-talk from the hamstring muscles.
