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Short term bed rest reduces conduction velocity of individual motor units in leg muscles
No full textSpace permanence simulations such as prolonged bed-rest can mimic some of the physiological modifications in the human body and provide study conditions that are more accessible than during space flight. A short term bed-rest experiment was organized to simulate the effects of weightlessness for studying the adaptation to this condition. Eight healthy young volunteers were studied before and immediately after the 14 day periods of strict bed-rest.
Surface EMG signals were detected with linear electrode arrays from vastus medialis, vastus lateralis and tibialis anterior muscle during isometric voluntary contractions at 20% MVC. Motor unit action potentials (MUAPs) of individual motor units were extracted from the interference EMG signals with a partial decomposition algorithm and averaged.
MUAP templates generated by the same motor unit could be retrieved before and after bed-rest period. Muscle fiber conduction velocity (CV) was estimated from each averaged MUAP template and from the global EMG signal. Both global and single MU conduction velocity was observed to decrease by about 10% after the bed-rest period (p < 0.05). Amplitude and power spectral parameters did not significantly change after the bed-rest period.
It is concluded that a short term bed-rest reduces the CV of individual motor units without a significant effect on muscle force or on other electrophysiological parameters
Concentric ring electrode systems for non-invasive detection of single motor unit activity
No full textSensore per l'acquisizione di segnali bioelettrici da un muscolo anulare, in particolare per elettromiografia di superficie multicanale
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Effect of electrode array position and subcutaneous tissue thickness on conduction velocity estimation in upper trapezius muscle
No full textLongitudinal and transverse propagation of surface mechanomyographic waves generated by single motor unit activity.Med Biol Eng Comput. 2008 Sep;46(9):871-7. Epub 2008 Jun 10
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Surface EMG alterations induced by underwater recording. J Electromyogr Kinesiol. 2004 Jun;14(3): 325-31.
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