TY  - JOUR
A1  - Martinez-Valdes, Eduardo Andrés
A1  - Laine, C. M.
A1  - Falla, D.
A1  - Mayer, Frank
A1  - Farina, D.
T1  - High-density surface electromyography provides reliable estimates of motor unit behavior
JF  - Clinical neurophysiology
N2  - Objective: To assess the intra-and inter-session reliability of estimates of motor unit behavior and muscle fiber properties derived from high-density surface electromyography (HDEMG). Methods: Ten healthy subjects performed submaximal isometric knee extensions during three recording sessions (separate days) at 10%, 30%, 50% and 70% of their maximum voluntary effort. The discharge timings of motor units of the vastus lateralis and medialis muscles were automatically identified from HDEMG by a decomposition algorithm. We characterized the number of detected motor units, their discharge rates, the coefficient of variation of their inter-spike intervals (CoVisi), the action potential conduction velocity and peak-to-peak amplitude. Reliability was assessed for each motor unit characteristics by intra-class correlation coefficient (ICC). Additionally, a pulse-to-noise ratio (PNR) was calculated, to verify the accuracy of the decomposition. Results: Good to excellent reliability within and between sessions was found for all motor unit characteristics at all force levels (ICCs > 0.8), with the exception of CoVisi that presented poor reliability (ICC < 0.6). PNR was high and similar for both muscles with values ranging between 45.1 and 47.6 dB (accuracy > 95%). Conclusion: Motor unit features can be assessed non-invasively and reliably within and across sessions over a wide range of force levels. Significance: These results suggest that it is possible to characterize motor units in longitudinal intervention studies. (C) 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
KW  - High-density surface EMG
KW  - Motor unit decomposition
KW  - Conduction velocity
KW  - Motor unit discharge rate
KW  - Vastus lateralis
KW  - Vastus medialis
Y1  - 2016
U6  - https://doi.org/10.1016/j.clinph.2015.10.065
SN  - 1388-2457
SN  - 1872-8952
VL  - 127
SP  - 2534
EP  - 2541
PB  - Elsevier
CY  - Clare
ER  -