Age-specific differences in the time-frequency representation of surface electromyographic data recorded during a submaximal cyclic back extension exercise: a promising biomarker to detect early signs of sarcopenia

Table 6 Test-retest reliability of the main outcome variables derived from the RMS-EMG and IMDF-EMG recorded on three different test days

	IMDF								RMS
	Intercept				Slope normalized to Intercept				Intercept				Slope normalized to Intercept
	Eccentric		Concentric		Eccentric		Concentric		Eccentric		Concentric		Eccentric		Concentric
	D^a	SEM	D^a	SEM	D^a	SEM	D^a	SEM	D^a	SEM	D^a	SEM	D^a	SEM	D^a	SEM
All electrodes	0.80	4.28	0.83	3.91	0.81	0.05	0.79	0.04	0.87	0.05	0.90	0.09	0.87	1.24	0.90	0.12
< 50	0.83	4.08	0.86	3.58	0.79	0.06	0.74	0.05	0.89	0.05	0.90	0.10	0.86	1.72	0.87	0.14
> 50	0.74	4.53	0.78	4.35	0.76	0.04	0.79	0.03	0.81	0.04	0.89	0.08	0.83	0.07	0.93	0.07
Multifidus (L5)	0.85	4.96	0.87	4.53	0.73	0.08	0.83	0.06	0.63	0.09	0.78	0.13	0.73	3.67	0.76	0.21
< 50	0.84	5.50	0.86	4.81	0.63	0.09	0.85	0.06	0.63	0.10	0.80	0.14	0.73	4.97	0.73	0.27
> 50	0.80	5.28	0.84	5.06	0.71	0.08	0.70	0.07	0.53	0.07	0.68	0.12	0.65	0.09	0.78	0.13
Longissimus (L2)	0.89	4.09	0.91	3.46	0.63	0.09	0.73	0.06	0.69	0.08	0.76	0.15	0.46	0.76	0.80	0.19
< 50	0.90	4.50	0.91	3.79	0.68	0.09	0.71	0.07	0.71	0.10	0.74	0.19	0.40	1.15	0.74	0.25
> 50	0.88	3.70	0.90	3.26	0.45	0.08	0.70	0.05	0.59	0.07	0.71	0.13	0.58	0.17	0.84	0.13
Iliocostalis lumb. (L1)	0.91	2.55	0.90	2.56	0.71	0.05	0.56	0.05	0.82	0.06	0.84	0.13	0.76	0.29	0.81	0.15
< 50	0.91	2.94	0.89	2.98	0.74	0.06	0.49	0.06	0.84	0.07	0.83	0.15	0.70	0.43	0.69	0.22
> 50	0.91	2.10	0.91	2.03	0.61	0.04	0.66	0.04	0.68	0.06	0.81	0.11	0.73	0.09	0.90	0.09
Most negative electrode	0.86	2.90	0.89	2.58	0.81	0.06	0.73	0.05	0.83	0.06	0.84	0.11	0.74	0.28	0.81	0.14
< 50	0.85	3.32	0.89	2.96	0.78	0.06	0.64	0.06	0.85	0.06	0.86	0.12	0.74	0.38	0.79	0.17
> 50	0.89	2.33	0.90	2.08	0.76	0.05	0.73	0.04	0.75	0.05	0.78	0.11	0.74	0.09	0.83	0.09

ISSN: 1743-0003