Mechanomyographic and electromyographic time and frequency domain responses during submaximal to maximal isokinetic muscle actions of the biceps brachii

Abstract

The purpose of this investigation was to determine the mechanomyographic (MMG) and electromyographic (EMG) amplitude and mean power frequency (MPF) versus torque relationships during isokinetic muscle actions of the biceps brachii. Twelve adults [mean (SD) age, 22.2 (2.7) years] performed submaximal to maximal isokinetic muscle actions of the dominant forearm flexors. Following determination of isokinetic peak torque (PT), the subjects randomly performed submaximal muscle actions in 20% increments from 20% to 80% PT. Polynomial regression analyses indicated linear increases in both MMG (r2=0.984) and EMG (r2=0.988) amplitude to 100% PT. There were no significant (P>0.05) relationships, however, for MMG and EMG MPF versus isokinetic torque. The results demonstrated similar responses for MMG and EMG in both the time and frequency domains. These findings suggested that simultaneous examination of MMG and EMG amplitude and MPF may be useful for describing the unique motor control strategies that modulate dynamic torque production. Furthermore, the results indicated that dynamic muscle actions can be used when applying techniques that require a linear EMG amplitude versus torque relationship.

Effect of diathermy on muscle temperature, electromyography, and mechanomyography

“…In the present study, MMG IMF increased up to Ϸ50% MVC, then plateaued to 90% MVC (Fig. 3), which was consistent with the findings of Coburn et al 8 and Beck et al 4 With further validation, it is possible that the frequency domain of the MMG signal may be useful as a noninvasive tool to estimate the global firing rate of active muscles during isometric ramp contractions. The subtle differences among the findings of our study and those of Beck et al 4 and Coburn et al 8 may be related to differences between isometric step and ramp contractions.…”

“…These findings were attributed to the shift in contributions to force production from motor unit recruitment to rate coding from 60%-80% MVC. Indeed, previous studies from our laboratory have reported similar increases in MMG center frequency during isometric step 4 and ramp 37 contractions. Coburn et al 8 demonstrated a nonsignificant increase in MMG center frequency with increasing isometric force production for the vastus medialis muscle, while Beck et al 4 reported significant increases in MMG center frequency for the biceps brachii muscle during submaximal to maximal isometric step contractions.…”

“…Many previous studies have observed similar increases in EMG amplitude with increases in force production during both isometric step 4,8 and ramp 5,37 contractions. Traditional surface EMG amplitude provides a global indication of muscle activation, which can be affected by motor unit recruitment and the firing rates of the active motor units.…”

“…Traditional surface EMG amplitude provides a global indication of muscle activation, which can be affected by motor unit recruitment and the firing rates of the active motor units. 4,10,14 Interestingly, the patterns of response for EMG amplitude during the isometric ramp contractions in this study were unaltered by any of the treatment conditions (diathermy, sham-diathermy, and control). This finding was consistent with the conclusion of Krause et al 25 that, ".…”

Understanding Gesture Expressivity through Muscle Sensing

“…In the field of biomedical engineering, muscle activation and articulation have been exploited to control prosthetic limb systems [Saridis and Gootee 1982;Silva et al 2005;Castellini and van der Smagt 2009;Farina et al 2014]. Because muscle sensing provides insights not only on volitional control but also on sensorimotor control strategies, it has been applied to the monitoring of muscle fatigue [Barry et al 1992;Tarata 2003], the evaluation of muscle functions and responses to stimuli [Beck et al 2004;Kuriki and Azevedo 2012] and neurophysiological assessment [Orizio et al 1992;Orizio et al 1997].…”