Evaluation of human dynamic contraction by phonomyography

Abstract

Phonomyogram (PMG, or acoustic myogram) is known to increase with force in isometric contractions. We investigated this relationship for dynamic contractions against different inertias. PMG and surface electromyogram (EMG) from biceps brachii and brachioradialis muscles were simultaneously recorded with the angular acceleration of elbow flexions. These were self-initiated movements (30 degrees) toward a fixed target and performed against two different inertias. PMG and EMG were integrated from the onset of the signal to the end of the acceleration phase. Phono- and electromechanical delays were also measured. For integrated EMG (iEMG), there was a linear relationship between integrated PMG (iPMG) and force, the slope of which did not depend on inertia. There was also a linear relationship between iPMG or iEMG and angular acceleration, with a higher slope for the highest inertia condition. There was also a family of linear relationships between iPMG or iEMG and angular acceleration, and their slopes depended on inertia. Measurements of the phono- and electromechanical delays showed that onset of PMG followed that of EMG but preceded onset of acceleration. It is suggested that PMG expresses tension of the underlying muscle contractile elements. Given the simplicity of the PMG method, we conclude that PMG allows convenient evaluation of muscle tension during human dynamic contraction.

Time and frequency domain analysis of acoustic signals from a human muscle

“…These results confirm earlier studies on human muscles in situ showing positive relationships between PMG and force during voluntary contractions and fatigue, 10,12,15,17,18 and also confirm earlier studies on the human diaphragm, 16 and a small hand muscle, 5,18 showing a good relationship between evoked acoustic responses and evoked twitch force during artificially excited contractions. It thus reinforces a previous conclusion that the amplitude of the phonomyogram can be employed as a noninvasive indicator of force production.…”

Evaluation of the respiratory muscular function by means of diaphragmatic mechanomyographic signals in copd patients

“…It has been observed that the amplitude of both LF contraction components [2]- [5] and HF contraction components [1], [6]- [8] of the muscular movement increase with the contraction force. The rationale for inferring the contraction muscle force, from the amplitude of the LF and HF components of the muscle movement, is that the signal constitutes the summation of muscle fibers movement from the recruited muscle motor units and their firing rate.…”

Gender Comparisons of Mechanomyographic Amplitude and Mean Power Frequency versus Isometric Torque Relationships

“…Simultaneous measurements of MMG and EMG have been used to examine the dissociation between the electrical and mechanical events (excitationcontraction coupling) that occurs with fatigue (Stokes & Dalton, 1991) and to examine factors related to electromechanical and phonomechanical delay (Petitjean, Maton, & Cnockaert, 1992). In addition, recent studies have examined the MMG amplitude and frequency responses during maximal concentric and eccentric isokinetic muscle actions (Cramer et al, 2002b;2002c;Ebersole et al, 2000;Evetovich et al, 1999), as well as maximal and submaximal cycle ergometry Perry et al, 2001a;2001b;Shinohara, Kouzaki, Yoshihisa, & Fukunaga, 1997;Stout, Housh, Johnson, Evetovich, & Smith, 1997).…”