TY - JOUR
T1 - The effect of epoch length on time and frequency domain parameters of electromyographic and mechanomyographic signals
AU - Keller, Joshua L.
AU - Housh, Terry J.
AU - Camic, Clayton L.
AU - Bergstrom, Haley C.
AU - Smith, Doug B.
AU - Smith, Cory M.
AU - Hill, Ethan C.
AU - Schmidt, Richard J.
AU - Johnson, Glen O.
AU - Zuniga, Jorge M.
N1 - Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/6
Y1 - 2018/6
N2 - The selection of epoch lengths affects the time and frequency resolution of electromyographic (EMG) and mechanomyographic (MMG) signals, as well as decisions regarding the signal processing techniques to use for determining the power density spectrum. No previous studies, however, have examined the effects of epoch length on parameters of the MMG signal. The purpose of this study was to examine the differences between epoch lengths for EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF from the VL and VM muscles during MVIC muscle actions as well as at each 10% of the time to exhaustion (TTE) during a continuous isometric muscle action of the leg extensors at 50% of MVIC. During the MVIC trial, there were no significant (p > 0.05) differences between epoch lengths (0.25, 0.50, 1.00, and 2.00-s) for mean absolute values for any of the EMG or MMG parameters. During the submaximal, sustained muscle action, however, absolute MMG amplitude and MMG MPF were affected by the length of epoch. All epoch related differences were eliminated by normalizing the absolute values to MVIC. These findings supported normalizing EMG and MMG parameter values to MVIC and utilizing epoch lengths that ranged from 0.25 to 2.00-s.
AB - The selection of epoch lengths affects the time and frequency resolution of electromyographic (EMG) and mechanomyographic (MMG) signals, as well as decisions regarding the signal processing techniques to use for determining the power density spectrum. No previous studies, however, have examined the effects of epoch length on parameters of the MMG signal. The purpose of this study was to examine the differences between epoch lengths for EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF from the VL and VM muscles during MVIC muscle actions as well as at each 10% of the time to exhaustion (TTE) during a continuous isometric muscle action of the leg extensors at 50% of MVIC. During the MVIC trial, there were no significant (p > 0.05) differences between epoch lengths (0.25, 0.50, 1.00, and 2.00-s) for mean absolute values for any of the EMG or MMG parameters. During the submaximal, sustained muscle action, however, absolute MMG amplitude and MMG MPF were affected by the length of epoch. All epoch related differences were eliminated by normalizing the absolute values to MVIC. These findings supported normalizing EMG and MMG parameter values to MVIC and utilizing epoch lengths that ranged from 0.25 to 2.00-s.
KW - EMG
KW - Epoch length
KW - MMG
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U2 - 10.1016/j.jelekin.2018.04.003
DO - 10.1016/j.jelekin.2018.04.003
M3 - Article
C2 - 29704787
AN - SCOPUS:85046159658
SN - 1050-6411
VL - 40
SP - 88
EP - 94
JO - Journal of Electromyography and Kinesiology
JF - Journal of Electromyography and Kinesiology
ER -