Table 1.

Results.

SMT	Depth/Pressure	Layer	SMT reliability				Interrater reliability
			Cor	Linear regression formula	R2	p value	ICC	95% CI	SEM	MDC
Shore Durometer	NA	1	0.92***	(− 0.0525 + 0.349 * RV)	0.85	< 0.001	0.69	(− 0.42 to 0.93)	0.16	0.45
STCM	5 mm	1	0.55 +	(0.1211 + 0.176 * RV)	0.35	0.096	0.12 +	(− 0.18 to 0.59)	0.42	1.15
	10 mm	1	0.70* +	(0.0228 + 0.0758 * RV)	0.48	0.037	0.18 +	(− 0.31 to 0.7)	0.10	0.28
MyotonPRO Stiffness	NA	1	0.94***	(0.0061 + 0.0757 * RV)	0.88	< 0.001	0.98***	(0.86 to 1)	0.01	0.02
IndentoPRO	2 mm	1	0.88**	(− 0.063 + 0.1934 * RV)	0.78	0.002	0.78*	(0.05 to 0.95)	0.09	0.24
	5 mm	1	0.71*	(− 0.039 + 0.1867 * RV)	0.50	0.032	0.51	(− 0.61 to 0.88)	0.20	0.56
	8 mm	1	0.87**	(0.0176 + 0.0942 * RV)	0.75	0.0025	0.76*	(− 0.11 to 0.95)	0.04	0.10
	10 mm	1	0.90**	(− 0.0222 + 0.0956 * RV)	0.81	< 0.001	0.82*	(0.24 to 0.96)	0.03	0.09
Ultrasound	5 kPasc	1	NA	NA	NA	NA	NA	NA	NA	NA
	10 kPasc	1	0.20 +	(− 0.0158 + 0.0715 * RV)	0.01	0.803	0.08	(− 0.36 to 0.57)	0.22	0.61
	15 kPasc	1	0.10 +	(0.093 + 0.0753 * RV)	0.01	0.809	0.14 +	(− 0.17 to 0.61)	0.23	0.63
Shore durometer	NA	2	0.77*	(0.1559 + 0.0399 * RV)	0.59	0.016	0.71	(− 0.3 to 0.93)	0.06	0.17
STCM	5 mm	2	0.65 +	(− 0.0054 + 0.1872 * RV)	0.46	0.043	0.31 +	(− 0.99 to 0.82)	0.27	0.76
	10 mm	2	0.93***	(0.2128 + 0.0453 * RV)	0.86	< 0.001	0.8*	(0.05 to 0.96)	0.05	0.13
MyotonPRO Stiffness	NA	2	0.98***	(0.0193 + 0.0208 * RV)	0.95	< 0.001	0.99***	(0.94 to 1)	0.00	0.01
IndentoPRO	2 mm	2	0.97***	(0.0791 + 0.1756 * RV)	0.94	< 0.001	0.82*	(− 0.03 to 0.96)	0.10	0.28
	5 mm	2	0.97***	(0.0785 + 0.16 * RV)	0.94	< 0.001	0.81*	(0.16 to 0.96)	0.09	0.25
	8 mm	2	0.98***	(0.0887 + 0.1321 * RV)	0.96	< 0.001	0.75*	(0.01 to 0.94)	0.07	0.20
	10 mm	2	0.98***	(0.0714 + 0.121 * RV)	0.96	< 0.001	0.71	(− 0.24 to 0.93)	0.08	0.22
Ultrasound	5 kPasc	2	0.80**	(0.7334 + 0.8173 * RV)	0.64	0.009	0.44	(− 1.63 to 0.87)	2.31	6.40
	10 kPasc	2	0.89**	(0.6956 + 0.6704 * RV)	0.79	0.001	0.74*	(− 0.17 to 0.94)	0.65	1.80
	15 kPasc	2	0.95***	(0.7275 + 0.7006 * RV)	0.90	< 0.001	0.82*	(0.1 to 0.96)	0.55	1.54
Shore Durometer	NA	4	0.53	(0.026 + 0.0237 * RV)	0.28	0.144	0.51	(− 0.4 to 0.88)	0.04	0.10
STCM	5 mm	4	0.05 +	(0.0899 + 0.0554 * RV)	0.05	0.562	0.07 +	(− 0.7 to 0.69)	0.38	1.04
	10 mm	4	0.92***	(− 0.0502 + 0.0971 * RV)	0.85	< 0.001	0.93***	(0.71 to 0.98)	0.03	0.09
MyotonPRO Stiffness	NA	4	0.91***	(0.0076 + 0.0181 * RV)	0.84	< 0.001	0.94**	(0.61 to 0.99)	0.01	0.01
IndentoPRO	2 mm	4	0.96***	(− 0.0242 + 0.1158 * RV)	0.92	< 0.001	0.96***	(0.82 to 0.99)	0.02	0.06
	5 mm	4	0.96***	(− 0.0361 + 0.0996 * RV)	0.92	< 0.001	0.97**	(0.38 to 0.99)	0.02	0.06
	8 mm	4	0.92***	(0.0087 + 0.1037 * RV)	0.85	< 0.001	0.96**	(0.67 to 0.99)	0.02	0.06
	10 mm	4	0.97***	(− 0.0052 + 0.1471 * RV)	0.93	< 0.001	0.96***	(0.71 to 0.99)	0.04	0.10
Ultrasound	5 kPasc	4	0.92***	(− 0.2829 + 0.471 * RV)	0.84	< 0.001	0.82*	(0.01 to 0.96)	0.27	0.75
	10 kPasc	4	0.87**	(− 0.198 + 0.5139 * RV)	0.76	0.0022	0.87**	(0.45 to 0.97)	0.26	0.71
	15 kPasc	4	0.96***	(− 0.0585 + 0.5778 * RV)	0.91	< 0.001	0.94***	(0.74 to 0.99)	0.16	0.45

ICC estimates and their 95% CI were calculated using the R package “irr” version 0.84.1 based on a 2-way random-effects model with absolute agreement. + Not normally distributed data were log 10 transformed for ICC calculations; correlations were accordingly calculated with the Spearman’s rank correlation coefficient instead of the Pearson product-moment correlation. Values that show at least a high correlation (r > 0.8) are printed in bold type. NA. Data could not be measured. Layer 1: Cutis. Layer 2: Subcutaneous connective tissue. Layer 3: Fascia profunda (data not shown, since none of our assessment methods was able to yield significant stiffness differences between the different layer variants in this 1 mm thin layer). Layer 4: Erector spinae muscle.

Significant at the level *< 0.05; **< 0.01; ***< 0.001.