MECHANOMYOGRAPHIC MEAN POWER FREQUENCY AND POWER OUTPUT DURING MAXIMAL, CONCENTRIC ISOKINETIC MUSCLE ACTIONS

Abstract

The purpose of this investigation was to examine the relationships between mechanomyographic (MMG) mean power frequency (MPF) and power output (PO) for the superficial muscles of the quadriceps femoris (vastus lateralis = VL, rectus femoris = RF, and vastus medialis = VM) during maximal, concentric isokinetic muscle actions. Twenty-three adults (age ± SD = 22 ± 3 years) volunteered to perform knee extensions at velocities of 60, 120, 180, 240, and 300°·s−1 on a Cybex 6000 dynamometer. Piezoelectric MMG recording sensors were placed over the VL, RF, and VM muscles. The frequency spectrums of the MMG signals from each muscle were determined using discrete fourier transformations, and PO was determined by the dynamometer software. PO increased (p < 0.05) from 60 to 180°·s−1 and then plateaued, while MMG MPF (marginal means collapsed across muscle) remained unchanged between 60 and 240°·s−1 and then increased to 300°·s−1. These findings indicated that each of the superficial muscles of the quadriceps femoris (VL, RF, and VM) exhibited the same velocity-related pattern for MMG MPF. There were, however, velocity-related dissociations between MMG MPF and PO.Figure: No caption Available