Table 4 . Distribution of measured posture in the three categories: low, noticeable and critical.

		Categories for measured posture (percentage of number of subjects)
DOF	Machine group	Low	Noticeable	Critical	p-value
Trunk inclination sagittal	C	11 (100)	0 (0)	0 (0)	< 0.001
	U	1 (2.9)	2 (5.9)	31 (91.2)
Trunk inclination lateral	C	11 (100)	0 (0)	0 (0)	0.57
	U	33 (97.1)	1 (2.9)	0 (0)
Back torsion lateral	C	11 (100)	0 (0)	0 (0)	0.49
	U	30 (88.2)	3 (8.8)	1 (2.9)
Head inclination sagittal	C	6 (54.5)	4 (36.4)	1 (9.1)	< 0.001
	U	1 (2.9)	7 (20.6)	26 (76.5)
Neck torsion lateral	C	11 (100)	0 (0)	0 (0)	0.57
	U	33 (97.1)	1 (2.9)	0 (0)

Note: Data are given as the number of subjects and their percentage in the machine group p-values are given as the result of the chi-squared test.