Biomechanical analysis of lifting on stable versus unstable surfaces—a laboratory-based proof-of-concept study

Table 4 Mean and maximal torque (Nmm) on hip, knee, and back joints during the two movement phases. Median (min, max) (n = 28)

	Stable			Slightly unstable			Unstable			Friedman	Wilcoxon Paired sign-rank (Bonferroni-adjusted)
	Median	Min	Max	Median	Min	Max	Median	Min	Max	p-value	stable vs unstable	stable vs slightly unstable	slightly unstable vs unstable
Hip
Down
Mean	543.55	152.3	731.0	536.6	114.2	703.3	522.1^a	121.45^a	703.15^a	0.607
Max	1227.1	468.65	1866.25	1183.95	470.0	1797.35	1125.0^a	469.7^a	1799.5^a	0.304
Up
Mean	558.6	67.1	1175.4	553.85	67.25	1193.3	517.5^a	101.75^a	1135.25^a	0.304
Max	1379.3	522.9	2096.05	1392.7	469.7	2129.05	1260.7^a	457.65^a	1889.7^a	0.63
Knee
Down
Mean	230.0	-57.7	761.65	280.55	-18.0	619.6	216.75	-3.9	591.5	0.012	0.061 (0.184)	0.285 (0.855)	0.003 (0.010)
Max	442.0	208.0	1125.65	449.15	261.15	1027.4	398.15	253.65	895.7	0.131
Up
Mean	67.0	-467.35	360.35	62.7	-396.8	296.55	-48.8	-437.65	405.7	0.113
Max	359.5	-165.45	1191.65	365.85	-210.75	953.6	320.7	-211.05	890.5	0.005	0.001 (0.004)	0.229 (0.229)	0.045 (0.135)
Lower back
Down
Mean	627.3	158.8	994.7	683.9	120.9	950.7	625.3^a	131.6^a	1065.2^a	0.446
Max	1698.0	658.9	2611.5	1643.1	713.5	2581.9	1552.9^a	737.7^a	2591.7^a	0.015	0.018 (0.050)	0.008 (0.025)	0.782 (1.000)
Up
Mean	862.0	61.0	1875.7	836.5	33.5	1942.8	808.5^a	83.2^a	1795.3^a	0.248
Max	1988.0	773.0	3045.6	1904.2	737.3	3226.5	1811.3^a	683.9^a	2775.9^a	0.06

Significant differences (p < 0.05) in bold
Torque expressed in Nmm: positive numbers = flexion, negative numbers = extension
^an = 26

ISSN: 2055-5784