Surface mechanomyogram reflects the changes in the mechanical properties of muscle at fatigue

Orizio, Claudio; Diemont, B.; Esposito, Fabio; Alfonsi, Enrico; Parrinello, Giovanni; Moglia, A.; Veicsteinas, Arsenio

doi:10.1007/s004210050593

Cited by 70 publications

(76 citation statements)

References 37 publications

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“…As the fusion state of muscle fiber is caused by an inadequate fiber relaxation between impulses, its magnitude can be determined by the motor unit firing frequency and shortening and relaxation velocity of the activated muscle fibers. Therefore, the MMG can be used for quantifying the time-course changes in muscle fiber contractile properties when the fiber is activated with electrical stimulation, as the firing rate can be controlled (Bichler and Celichowski 2001b;Kimura et al 2003;Orizio et al 1999). In addition, considering that the MMG is recorded laterally to the muscle bundle, prospective advantages of using MMG instead of external force output are as follows: (1) to assess motor units' contractile properties by means of electrical stimulation, such as when the recording of the force output of the muscle studied is difficult (Esposito et al 1998;Orizio 1993;Yoshitake et al 2001), and (2) to directly assess the mechanical function of an individual muscle during the simultaneous contraction of synergistic muscles (Yoshitake and Moritani 1999).…”

Section: Introductionmentioning

confidence: 99%

Mechanomyographic responses in human biceps brachii and soleus during sustained isometric contraction

et al. 2004

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The purpose of this study was to elucidate the responses of the mechanomyogram (MMG) from two apparently different muscles (biceps brachii and soleus) during a sustained voluntary contraction at 50% maximum voluntary contraction. The MMG and surface electromyogram (EMG) were recorded from human biceps brachii and soleus during sustained elbow flexion and plantar flexion, respectively. Results indicated that the slope coefficient of rise in EMG amplitude as a function of time for the biceps was significantly greater than that for the soleus ( P<0.001). On the contrary, the MMG amplitude of the biceps showed a significant increase during the initial phase of sustained contraction ( P<0.05); however, when exhaustion was approached the amplitude declined significantly ( P<0.05). In the soleus muscle the decrease in MMG amplitude toward exhaustion occurred to a much lesser extent than that observed in the biceps. This difference could be attributed to the nature of the fusion state of the underlying muscle fibers. That is, the great extent of fusion observed in the biceps may be as a result of a greater quantity of fatigable motor units. In addition, the absence of MMG reduction in the soleus would indicate the absence of fatigue-induced slowing of contractile machinery and/or the lack of full activation (tetanus) of muscle fibers even at the exhaustion phase of plantar flexion.

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Section: Introductionmentioning

confidence: 99%

Mechanomyographic responses in human biceps brachii and soleus during sustained isometric contraction

et al. 2004

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“…This property of the MMG was demonstrated by the previous experiment with electrical stimulation [7]. Namely, higher stimulation frequency (i.e., firing rate) produces mechanical fusing of muscle fibers, which results in a reduction in fiber dimensional change, followed by a decrease in the MMG amplitude.…”

Section: Mmg and Mu Activation Strategymentioning

confidence: 72%

“…When the firing rate of the MUs increases, contraction of muscle fiber is enhanced whereas a lateral deformation of muscle fiber is reduced, which leads to a marked decrease in the MMG amplitude [4,5,7]. Moreover, it is suggested that the mean power frequency of the MMG is closely related to the mean firing rate of the MUs [4,5].…”

Section: Introductionmentioning

confidence: 94%

Time‐frequency analysis of mechanomyogram during sustained contractions with muscle fatigue

Itoh

Akataki

Mita

et al. 2003

Systems & Computers in Japan

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SUMMARYThe mechanomyogram (MMG) is a recording of mechanical oscillation that is detectable on the body surface overlying the muscle. It is considered that the MMG is produced by lateral dimensional changes in active muscle fibers, which generate pressure waves, and reflects the mechanical activity of muscle. The present study was designed to examine the MMG behavior during sustained contraction at a constant level of force up to muscle fatigue, and to determine that the MMG reflects the specific motor unit (MU) activation strategy resulting from muscle fatigue. In the experiment, isometric contractions of biceps brachii muscles at 20 and 80% of the maximal voluntary contraction (20 and 80% MVC) were selected. The recorded MMG was analyzed by the short-time Fourier transform, and the root mean squared amplitude (RMS) and mean power frequency (MPF) were calculated every 0.1 s. It was found that the RMS of the MMG at 20% MVC decreased somewhat from the onset of contractions, then gradually increased. The MPF initially increased and then remained constant. At 80% MVC, on the other hand, the RMS continued to decrease. The MPF initially increased and then decreased. These trends in the RMS and MPF seem to reflect an alteration in the MU activation strategy resulting from muscle fatigue. The MMG is considered to be one of the useful tools in monitoring muscle fatigue.

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“…The mechanomyogram (MMG), originated from the dimensional changes of activated muscle Wbers, has been attracting extensive attention because it is able to evaluate changes in muscle mechanical properties, i.e., twitch force and contraction and relaxation speed, during isometric contraction (Bichler and Celichowski 2001;Gobbo et al 2006;Kimura et al 2003;Moritani et al 2005;Orizio et al 1999). Especially, it is practically favorable that MMG could provide some information regarding the fatiguerelated impairment in muscle mechanical properties during submaximal sustained contraction.…”

Section: Introductionmentioning

confidence: 99%

Mechanomyographic responses in quadriceps muscles during fatigue by continuous cycle exercise

et al. 2008

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The present study examined whether the mechanomyogram (MMG) could assess the fatigue-related changes in muscle mechanical properties during cycle exercise. In eight male subjects, the MMG signals were measured in vastus lateralis and rectus femoris by electret condenser microphones. It was found that the integrated MMG (iMMG) showed non linear increase against workload during continuous, incremental cycle exercise and the onset of abrupt changes in iMMG coincided with the ventilatory threshold (VT). Specifically, iMMG in vastus lateralis showed a significant decrement in the rate of increase against workload above VT, reflecting the fatigue-induced impairment of contractile properties of the fibers of active motor units. These results suggest that the MMG measured by electret condenser microphone could be practically used to retrieve the fatigue-related changes in muscle mechanical properties during cycle exercise.

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Surface mechanomyogram reflects the changes in the mechanical properties of muscle at fatigue

Cited by 70 publications

References 37 publications

Mechanomyographic responses in human biceps brachii and soleus during sustained isometric contraction

Mechanomyographic responses in human biceps brachii and soleus during sustained isometric contraction

Time‐frequency analysis of mechanomyogram during sustained contractions with muscle fatigue

Mechanomyographic responses in quadriceps muscles during fatigue by continuous cycle exercise

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