Moreover, the average rectified value (ARV) and the mean frequency (MNF) of interference EMGs increased and decreased with simulated fatigue, respectively.
The results, expressed in terms of high-to-low energy ratio, normalized median frequency, spectral power difference and normalized average rectified value, suggest that the proposed method enables better ECG EMG separation quality than the reference methods.
MCG = Matched Control Group, FM = Fibromyalgic group, MVC = maximal voluntary contraction, CV = conduction velocity, MNF = mean spectral frequency, ARV = average rectified value; NS = non significative There were no statistically significant differences in the voluntary contractions at 30% MVC.
For each burst of energy in the spectrogram we computed the amplitude as the average rectified value (ARV) of the signal in an epoch of 20 ms centered on the instant of maximum energy of the spectrogram.
The initial values and rates of change in mean spectral frequency (MNF), average rectified value (ARV) and conduction velocity (CV) were computed off-line by means of numerical algorithms [ 30] using non-overlapping signal epochs of 0.5 seconds, thus generating 60 estimates of each variable during the 30-second contractions.
The values plotted (rectified conductivity, κr) are the results of the application of this equation.
The effect of moving average window width on the range of values of rectified and integrated EMG signals was tested on a theoretical model presented by Veternik and co-workers (Veterník M, Šimera M, Jakuš J, and Poliaček I. Effect of moving average window width on integration of EMG signal).
Main Outcome Measures: Amount of change in mean rectified electromyographic activity (δ value) between walking with and without AFO.
These peaks were extracted from the rectified EMG as the maximum values within sliding windows of length [ 750 750 ms] which exceeded a subject-specific threshold set by visual inspection.
The null hypothesis, is that the mean values of the rectified SEMG and the mean time of swallowing would be statistically the same.
