Table 2.

Normalized lumbar extensor RMS SEMG amplitudes and kinematics

	<40		40-60		>60		Men		Women		Age			Gender			Age x gender
	(n:61)		(n:71)		(n:58)		(n:91)		(n:99)
	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	RSS	p-val		RSS	p-val		RSS	p-val
Normalized RMS sEMG amplitude:
standing/80 % MVC	31.94	25.35	41.09	22.36	66.55	41.27	38.97	27.25	52.32	36.92	197.16	0.001	*	38.78	0.006	*	7.94	0.431	ns
halfflexion/80 % MVC	74.00	75.33	80.28	28.80	89.48	40.36	77.66	62.71	84.21	38.14	41.33	0.241	ns	9.77	0.440	ns	60.07	0.112	ns
maximum flexion/80 % MVC	40.85	43.31	68.66	36.41	89.47	49.30	59.26	44.30	72.36	48.46	378.90	0.001	*	31.77	0.071	ns	1.85	0.930	ns
Relative RMS sEMG amplitude changes between isometric positions (in percent):
standing – half flexion	42.06	72.98	39.20	25.57	22.94	29.25	38.70	60.88	31.89	30.48	61.78	0.046	*	9.62	0.449	ns	27.82	0.329	ns
standing - maximum flexion	8.91	41.04	27.57	32.55	22.93	37.38	20.29	36.04	20.04	39.13	62.62	0.011	*	0.35	0.834	ns	2.19	0.859	ns
half - maximum flexion	-33.15	56.08	-11.63	26.72	-0.01	30.10	-18.40	53.58	-11.85	25.52	172.54	0.001	*	6.31	0.399	ns	43.80	0.063	ns
Half Flexion Relaxation ratio (HFR):
half/maximum flexion	3.01	2.86	1.42	0.78	1.16	0.61	2.12	2.41	1.61	1.20	0.61	0.001	*	0.05	0.093	ns	0.05	0.199	ns
Landmark positions (in degrees relative to the vertical):
mean standing TH4	13.87	3.53	15.37	4.57	14.42	4.76	15.17	4.32	14.08	4.34	0.40	0.159	ns	0.27	0.095	ns	0.26	0.272	ns
mean standing L5	17.54	5.49	16.00	6.78	15.37	5.92	13.37	5.49	18.99	5.51	1.06	0.041	*	8.15	0.001	*	0.26	0.434	ns
Changes in position angles (in degrees):
hip region (standing – maximum flexion)	53.08	11.72	58.34	11.80	59.85	12.42	54.94	11.50	59.10	12.61	7.81	0.005	*	4.10	0.026	*	1.59	0.320	ns
lumbothoracic region (standing – maximum flexion)	57.35	9.64	49.95	9.60	46.20	10.86	50.48	10.88	51.82	11.01	20.85	0.001	*	1.02	0.171	ns	0.89	0.433	ns
gross trunk region (standing – maximum flexion)	110.43	13.53	108.29	13.63	106.04	15.22	105.42	12.91	110.93	14.75	4.08	0.146	ns	9.21	0.006	*	4.25	0.132	ns
hip region (standing – half flexion)	24.80	5.63	28.23	5.81	26.95	5.45	25.99	5.22	27.43	6.22	2.09	0.002	*	0.37	0.135	ns	0.24	0.489	ns
lumbothoracic region (standing – half flexion)	26.72	13.10	26.85	9.30	27.43	10.28	26.37	9.22	27.55	12.23	0.10	0.923	ns	0.39	0.434	ns	0.43	0.688	ns
gross trunk region (standing – half flexion)	51.52	11.44	55.08	9.94	54.38	12.12	52.36	9.03	54.98	12.75	3.01	0.089	ns	1.53	0.144	ns	0.04	0.981	ns
% hip of gross trunk region (half flexion)	47.87	7.59	53.70	7.68	56.40	8.59	52.10	9.02	53.16	8.28	11.94	0.001	*	0.12	0.574	ns	0.06	0.925	ns
% lumbothoracic of gross trunk region (half flexion)	52.13	7.59	46.30	7.68	43.60	8.59	47.90	9.02	46.84	8.28	11.94	0.001	*	0.12	0.573	ns	0.06	0.929	ns
% hip of gross trunk region (maximum flexion)	50.69	16.20	52.18	11.14	50.85	10.41	50.71	11.47	51.83	13.85	0.18	0.892	ns	0.19	0.652	ns	2.91	0.212	ns
% lumbothoracic of gross trunk region (max flexion)	49.31	16.20	47.82	11.14	49.15	10.41	49.29	11.47	48.17	13.85	0.18	0.906	ns	0.19	0.634	ns	2.91	0.200	ns

RMS sEMG rout mean square surface electromyographic, *level of significance p < 0,05, ns not significant