Table 1.

Parameters of level of agreement derived from Bland Altman analyses for MRI and US measurements of hamstring muscles CSA at different portions of femur length.

Rater 1—MRI vs. US (MRI CSAs evaluated post US assessment, both in randomized order)
Muscle (distal—0%, to proximal—100%)	MRI CSA (cm2)	Mean bias (cm2) [%]	ULOA (cm2) [%]	LLOA (cm2) [%]	Pearson’s r (95% CI)
Semimembranosus
30% (n = 85)	10.07 ± 2.32	0.02 ± 1.2 [− 0.4%]	2.38 [24%]	− 2.37 [− 25%]	0.86 (0.79–0.90)
40% (n = 85)	8.09 ± 2.19	− 0.77 ± 1.38 [− 9%]	1.94 [23%]	− 3.5 [− 42%]	0.79 (0.69–0.86)
50% (n = 85)	4.51 ± 1.98	− 1.24 ± 1.37 [− 25%]	1.44 [49%]	− 3.94 [− 99%]	0.78 (0.68–0.85)
60% (n = 70)a	1.61 ± 1.15	− 0.99 ± 1.09 [− 53%]	1.15 [52%]	− 3.14 [− 159%]	0.64 (0.48–0.76)
Semitendinosus
30% (n = 85)	4.17 ± 1.82	0.33 ± 0.96 [3%]	2.23 [74%]	− 1.55 [− 67%]	0.84 (0.77–0.89)
40% (n = 85)	7.33 ± 1.72	0.44 ± 1.04 [7%]	2.48 [38%]	− 1.6 [− 23%]	0.84 (0.77–0.89)
50% (n = 85)	8.64 ± 2	0.26 ± 0.92 [4%]	2.08 [27%]	− 1.55 [− 19%]	0.90 (0.86–0.93)
60% (n = 85)	8.5 ± 2.01	− 0.34 ± 0.99 [− 4%]	1.6 [18%]	− 2.29 [− 26%]	0.87 (0.82–0.92)
Biceps femoris long head
30% (n = 85)	8.12 ± 2.26	1.19 ± 1.19 [16%]	3.54 [48%]	− 1.15 [− 16%]	0.85 (0.78–0.90)
40% (n = 85)	10.36 ± 2.19	0.77 ± 0.91 [8%]	2.56 [26%]	− 1.02 [− 10%]	0.90 (0.86–0.94)
50% (n = 85)	8.93 ± 1.84	− 0.36 ± 0.98 [− 4%]	1.55 [19%]	− 2.28 [− 27%]	0.83 (0.75–0.89)
60% (n = 84)a	5.96 ± 1.73	− 0.91 ± 1.16 [− 15%]	1.35 [22%]	− 3.18 [− 54%]	0.75 (0.64–0.83)
Biceps femoris short head
30% (n = 85)	5.71 ± 1.38	− 0.08 ± 0.91 [− 1%]	1.7 [34%]	− 1.88 [− 36%]	0.80 (0.71–0.86)
40% (n = 85)	3.71 ± 1.03	− 0.23 ± 0.83 [− 6%]	1.4 [37%]	− 1.88 [− 49%]	0.69 (0.56–0.79)
50% (n = 82)a	1.85 ± 0.74	− 0.63 ± 0.83 [− 29%]	1 [40%]	− 2.26 [− 99%]	0.37 (0.17–0.55)
60% (n = 0)a		–	–	–	–

Pearson’s r correlation coefficients are reported too.

ULOA upper limit of agreement, LLOA lower limit of agreement.

^aLower number of subjects due to not visible muscle