Figure 4.

Average rectified SEMG of baseline and during muscle activation for different electrode diameters. The dashed lines indicate the values obtained from disposable Ag/AgCl electrodes. (a) Baseline electrode noise; (b) SEMG amplitude during muscle contractions exerted by knee extension; (c) Signal to noise ratio (SNR). SEMG was measured on the rectus femoris with stretchable leg sleeves where circle electrodes in different diameters were embedded. Values were calculated by averaging three consecutive measurements from three leg-sleeve samples in each diameter. * p < 0.1 versus 0%, # p < 0.1 versus 10%. Non-parametric statistics verified all significances: the Kruskal–Wallis test was used to identify group differences with the Mann–Whitney U test used as a post hoc test.