. 2020 Jul 9;15(7):e0235545. doi: 10.1371/journal.pone.0235545

Table 4. Pairwise comparison (Wilcoxon signed-rank, n = 31) across test periods P1–P4 using muscle sEMG feature medians of the individual subjects.

Muscle feature	p-value
Muscle feature	P1 vs. P2	P1 vs. P3	P1 vs. P4	P2 vs. P3	P2 vs. P4	P3 vs. P4
corrms	0.013^*	<0.001^**	<0.001^**	<0.001^**	<0.001^**	0.088
corwl	0.015^*	<0.001^**	<0.001^**	<0.001^**	<0.001^**	0.046^*
orbrms	0.367	0.018^*	0.057	<0.001^**	<0.001^**	0.422
orbwl	0.422	0.010^*	0.008^**	<0.001^**	<0.001^**	0.953
levrms	0.829	0.001^**	0.015^*	<0.001^**	0.001^**	0.493
levwl	0.984	0.003^**	0.022^*	<0.001^**	0.001^**	0.784
zygrms	0.085	0.290	0.570	<0.001^**	0.023^*	0.433
zygwl	0.164	0.136	0.583	0.001^**	0.024^*	0.357
risrms	0.638	0.023^*	0.088	<0.001^**	0.003^**	0.597
riswl	0.597	0.048^*	0.071	0.002^**	0.004^**	0.456

Muscle areas: cor = corrugator supercilii, orb = orbicularis oculi, lev = levator labii superioris, zyg = zygomaticus major, and ris = risorius; feature transformations: rms = root mean square, and wl = waveform length.

*p < 0.05

**p < 0.01