Relationships between skinfold thickness and electromyographic and mechanomyographic amplitude recorded during voluntary and non-voluntary muscle actions

Abstract Introduction The purpose of this study was to examine possible correlations between skinfold thicknesses and the a terms from the log-transformed electromyographic (EMGRMS ) and mechanomyographic amplitude (MMGRMS )-force relationships, EMG M-Waves, and MMG gross lateral movements (GLM). Methods Forty healthy subjects performed a 6-s isometric ramp contraction from 5% to 85% of their maximal voluntary contraction with EMG and MMG sensors placed on the vastus lateralis (VL) and rectus femoris (RF). A single electrical stimulus was applied to the femoral nerve to record the EMG M-waves and MMG GLMs. Skinfold thickness was assessed at the site of each electrode. Pearson’s product correlation coefficients were calculated comparing skinfold thicknesses with the a terms from the log-transformed EMGRMS -and MMGRMS - force relationships, EMG M-waves, and MMG GLMs. Results There were no significant cor1relations ( p > 0.05) between the a terms and skinfold thicknesses for the RF and VL from the EMGRMS and MMGRMS -force relationships. However, there were significant correlations ( p < 0.05) between skinfold thicknesses and the EMG M-waves and MMG GLMs for the RF ( r = −0.521, −0.376) and VL ( r = −0.479, −0.484). Discussion Relationships were only present between skinfold thickness and the amplitudes of the EMG and MMG signals during the non-voluntary muscle actions.