Non-linear dose response effect of cathodal transcranial direct current stimulation on muscle strength in young healthy adults: a randomized controlled study

Table 4 Percentage changes from baseline of the upper extremity muscle strength on the non-dominant limb are presented as mean (SD) at posttest (POST) in each group

Muscles of the non-dominant limb	Groups	Percentage change from baseline	Within group comparison			Between group comparison
		POST [Mean (SD)]	Z	p value	Effect size	Overall	Post hoc
		POST [Mean (SD)]	Z	p value	Effect size	Overall	Comparison groups	p value
Elbow flexor	Sham tDCS	1.04 (3.98)	0.863	0.424	0.25	0.003**	Sham versus 1 mA	0.001**
	1.0 mA ctDCS	− 11.35 (8.25)	− 2.903	0.001**	0.84		Sham versus 1.5 mA	0.360
	1.5 mA ctDCS	− 4.29 (12.42)	− 1.255	0.233	0.36		Sham versus 2 mA	0.746
	2.0 mA ctDCS	− 0.33 (6.02)	− 0.392	0.733	0.11		1 mA versus 1.5 mA	0.178
							1 mA versus 2 mA	0.040*
							1.5 mA versus 2 mA	0.923
Elbow extensor	Sham tDCS	− 1.58 (6.98)	− 1.569	0.129	0.45	0.005**	Sham versus 1 mA	0.305
	1.0 mA ctDCS	− 10.84 (8.91)	− 2.934	< 0.001***	0.85		Sham versus 1.5 mA	0.454
	1.5 mA ctDCS	− 7.86 (8.08)	− 2.824	0.002**	0.82		Sham versus 2 mA	0.499
	2.0 mA ctDCS	4.49 (9.32)	0.863	0.424	0.25		1 mA versus 1.5 mA	0.994
							1 mA versus 2 mA	0.009**
							1.5 mA versus 2 mA	0.021*
Wrist extensor	Sham tDCS	− 1.11 (3.87)	− 1.412	0.176	0.41	0.001**	Sham versus 1 mA	0.020**
	1.0 mA ctDCS	− 13.47 (5.95)	− 3.059	< 0.001***	0.88		Sham versus 1.5 mA	0.998
	1.5 mA ctDCS	− 0.83 (9.47)	− 0.784	0.470	0.23		Sham versus 2 mA	0.833
	2.0 mA ctDCS	− 0.33 (9.19)	0.784	0.470	0.23		1 mA versus 1.5 mA	0.034*
							1 mA versus 2 mA	0.001***
							1.5 mA versus 2 mA	0.737

ISSN: 2052-1847