Reaction time can be measured during voluntary contractions with electrode array

Abstract

Reaction time (RT) is classically divided into premotor time (PMT) and electromechanical delay (EMD). However, the determination of the onset of electromyographic activity (EMG) during voluntary contraction remains questionable. In addition, the reliability of RT, PMT and EMD needs to be determined. Twelve participants performed two sessions of RT trials, separated by 5 min. RT was evaluated during voluntary isometric contractions of the elbow flexors, i.e., time between a light signal (stimulus) and the onset of the mechanical response. To assess EMD, an electrode array (64 channels) was used to accurately detect the onset of EMG activity. PMT represented the major part of the RT (~88%). Coefficients of variation were reasonably satisfactory for all parameters (range: 11·9-13·4%). The use of electrode array appears to be a relevant method to measure EMD. Moreover, sessions based on two trials are reliable enough to detect changes in RT components.

Interpreting Signal Amplitudes in Surface Electromyography Studies in Sport and Rehabilitation Sciences

“…It follows that one may reasonably conclude whether or not a muscle is “on” or “off” if the time of interest is >~200 ms (Dieterich et al, 2017 ). Finally, one can increase their confidence in knowing the state of a muscle by using multiple electrodes or HD-sEMG, which accounts for intramuscular heterogeneity (Dieterich et al, 2017 ; dos Anjos et al, 2017 ; Le Mansec et al, 2017 ).…”

“…Notwithstanding these points, if small errors are acceptable for the application in question (e.g., <200 ms; Dieterich et al, 2017 ), then sEMG can be very useful for this purpose. Finally, one can increase their confidence in knowing the state of the muscle by using multiple electrodes or HD-sEMG (Figure 4 ; Dieterich et al, 2017 ; dos Anjos et al, 2017 ; Le Mansec et al, 2017 ).…”

Intramuscular Pressure of Tibialis Anterior Reflects Ankle Torque but Does Not Follow Joint Angle-Torque Relationship

“…Electromechanical delay (EMD) is due to the natural link between mechanical and electrophysiological muscle characteristics. EMD is defined as the time lag between the activation of a muscle and force production at the tendon due to the underlying electromechanical processes of excitation-contraction coupling (Norman and Komi, 1979 ; Le Mansec et al, 2017 ). EMD provides a link between mechanical and electrophysiological quantities (Nordez et al, 2009 ).…”

Interpreting Signal Amplitudes in Surface Electromyography Studies in Sport and Rehabilitation Sciences

“…It follows that one may reasonably conclude whether or not a muscle is "on" or "off " if the time of interest is > ∼200 ms (Dieterich et al, 2017). Finally, one can increase their confidence in knowing the state of a muscle by using multiple electrodes or HD-sEMG, which accounts for intramuscular heterogeneity (Dieterich et al, 2017;dos Anjos et al, 2017;Le Mansec et al, 2017).…”

“…Notwithstanding these points, if small errors are acceptable for the application in question (e.g., <200 ms; Dieterich et al, 2017), then sEMG can be very useful for this purpose. Finally, one can increase their confidence in knowing the state of the muscle by using multiple electrodes or HD-sEMG (Figure 4; Dieterich et al, 2017;dos Anjos et al, 2017;Le Mansec et al, 2017).…”