Lumbar interspinous pressure pain threshold values for healthy young men and women and the effect of prolonged fully flexed lumbar sitting posture: An observational study

Table 1 The median value and quartiles, Wilcoxon signed rank test and effect size r for the whole study population regarding interspinous pressure pain thresholds before (pre-test) and after (post-test) exposure to prolonged flexed lumbar sitting posture

Variables	Pre-test median (quartiles)	Post-test median (quartiles)	Z-standardised test statistic	P value	Effect size r
L1-L2	397 (349, 448)	315 (256, 369)	-4.382	< 0.001	-0.60
L2-L3	361 (300, 441)	310 (251, 366)	-3.798	< 0.001	-0.52
L3-L4	339 (285, 398)	305 (244, 357)	-3.480	< 0.001	-0.47
L4-L5	316 (293, 397)	294 (230, 381)	-3.277	0.001	-0.45
All variables (L1-L2, L2-L3, L3-L4 and L4-L5)	359 (298, 400)	312 (252, 350)	-4.229	< 0.001	-0.56

Table 2 The median value and quartiles, Wilcoxon signed rank test and effect size r for women regarding interspinous pressure pain thresholds before (pre-test) and after (post-test) exposure to prolonged flexed lumbar sitting posture

Variables	Pre-test median (quartiles)	Post-test median (quartiles)	Z-standardised test statistic	P value	Effect size r
L1-L2	353 (314, 434)	295 (236, 346)	-3.180	0.002	-0.43
L2-L3	319 (271, 416)	286 (219, 347)	-2.830	0.005	-0.39
L3-L4	299 (281, 400)	261 (229, 338)	-2.551	0.011	-0.35
L4-L5	306 (265, 395)	233 (214, 351)	-2.691	0.007	-0.37
All variables (L1-L2, L2-L3, L3-L4 and L4-L5)	331 (288, 403)	269 (227, 344)	-2.970	0.003	-0.40

Table 3 The median value and quartiles, Wilcoxon signed rank test and effect size r for men regarding interspinous pressure pain thresholds before (pre-test) and after (post-test) exposure to prolonged flexed lumbar sitting posture

Variables	Pre-test median (quartiles)	Post-test median (quartiles)	Z-standardised test statistic	P value	Effect size r
L1-L2	405 (356, 518)	340 (284, 441)	-3.110	0.001	-0.42
L2-L3	379 (337, 421)	322 (288, 470)	-2.621	0.009	-0.36
L3-L4	370 (320, 453)	331 (264, 453)	-2.378	0.017	-0.32
L4-L5	321 (299, 474)	302 (275, 479)	-1.819	0.069	-0.25
All variables (L1-L2, L2-L3, L3-L4 and L4-L5)	366 (288, 403)	322 (227, 344)	-3.040	0.002	-0.41

Table 4 The median value, quartiles and Mann-Whitney U test comparing men and women for pressure pain threshold measurement pre and post prolonged flexed lumbar sitting posture

Variables	Pre-test			Post-test			Gender difference in change in PPT between pre and post (P value)
	Women median (quartiles)	Men median (quartiles)	P value	Women median (quartiles)	Men median (quartiles)	P value
L1-L2	353 (314, 434)	405 (358, 518)	0.14	295 (236, 346)	340 (284, 441)	0.09	0.96
L2-L3	319 (271, 416)	379 (337, 521)	0.09	286 (219, 347)	322 (288, 470)	0.08	0.92
L3-L4	299 (281, 400)	370 (320, 453)	0.16	261 (229, 338)	331 (264, 453)	0.09	0.88
L4-L5	306 (265, 395)	321 (299, 474)	0.25	233 (214, 351)	302 (275, 479)	0.12	0.13
All variables (L1-L2, L2-L3, L3-L4 and L4-L5)	331 (288, 403)	366 (298, 400)	0.10	269 (227, 344)	322 (285, 455)	0.10	0.55