Table 1.

Inter-method reliability indexes between the manual thresholding technique and automated thresholding algorithm for the right and left multifidus and erector spinae muscles at L4–L5 and L5–S1

Parameter	Right side			Left side
	Mean (SD)	ICC (95% CI)	SEM	Mean (SD)	ICC (95% CI)	SEM
Multifidus L4–L5
CSA (cm2)	9.77 (1.83)	0.99 (0.98–1.00)	0.18	9.39 (1.44)	0.98 (0.97–0.99)	0.20
FCSA (cm2)	4.39 (1.58)	0.84 (0.68–0.92)	0.63	4.44 (1.55)	0.90 (0.76–0.95)	0.49
Fat CSA (cm2)	5.38 (1.38)	0.83 (0.65–0.92)	0.57	4.95 (1.10)	0.80 (0.51–0.91)	0.49
Fat %	0.56 (0.12)	0.79 (0.57–0.90)	0.05	0.53 (0.12)	0.83 (0.55–0.92)	0.05
Erector spinae L4–L5
CSA (cm2)	16.36 (3.39)	0.98 (0.96–0.99)	0.48	17.35 (3.88)	0.99 (0.95–0.99)	0.39
FCSA (cm2)	7.25 (2.47)	0.96 (0.91–0.98)	0.49	9.64 (2.32)	0.94 (0.88–0.97)	0.57
Fat CSA (cm2)	9.11 (2.28)	0.94 (0.84–0.97)	0.56	9.64 (2.33)	0.91 (0.78–0.96)	0.70
Fat %	0.56 (0.10)	0.91 (0.81–0.95)	0.03	0.56 (0.10)	0.85 (0.70–0.93)	0.04
Multifidus L5–S1
CSA (cm2)	11.25 (1.75)	0.97 (0.90–0.97)	0.30	11.29 (1.53)	0.98 (0.96–0.99)	0.22
FCSA (cm2)	5.34 (1.94)	0.93 (0.86–0.96)	0.51	5.49 (1.65)	0.90 (0.80–0.95)	0.52
Fat CSA (cm2)	5.91 (1.27)	0.86 (0.72–0.93)	0.48	5.80 (1.21)	0.78 (0.54–0.89)	0.57
Fat %	0.53 (0.13)	0.90 (0.80–0.95)	0.04	0.52 (0.11)	0.82 (0.62–0.91)	0.05
Erector spine L5–S1
CSA (cm2)	11.26 (4.06)	0.97 (0.90–0.99)	0.70	11.43 (4.4)	0.95 (0.87–0.97)	0.98
FCSA (cm2)	3.77 (2.22)	0.91 (0.71–0.96)	0.67	3.88 (2.27)	0.94 (0.88–0.97)	0.62
Fat CSA (cm2)	7.49 (2.37)	0.97 (0.94–0.98)	0.41	7.55 (2.53)	0.91 (0.83–0.96)	0.68
Fat %	0.68 (0.11)	0.81 (0.48–0.92)	0.04	0.68 (0.10)	0.78 (0.50–0.90)	0.05

ICC intra-class correlation coefficient, CI confidence interval, SEM standard error of measurement, CSA cross-sectional area, FCSA functional cross-sectional area