Table 4.

Intra-rater reliability of the ultrasound measurements (direct method) in the feasibility study for the STCP group (n = 15). Data were expressed as typical error and intra-class coefficients (ICC) with their 95% confidence intervals (CI) and mean differences ± standard deviation (SD)

Muscle & Stage	Typical Error 95% CI	ICC 95% CI	Mean diff ± SD
EO R	0.65 (0.06–0.24)	0.81 (0.66–0.96)	− 0.19 ± 0.04
EO Ac	0.59 (0.07–0.18)	0.88 (0.76–0.97)	−0.10 ± 0.04
IO R	0.60 (0.06–0.20)	0.82 (0.86–0.98)	0.10 ± 0.08
IO Ac	0.62 (0.08–0.24)	0.80 (0.65–0.95)	0.11 ± 0.05
TrA R	0.64 (0.05–0.20)	0.82 (0.68–0.98)	0.17 ± 0.07
TrA Ac	0.63 (0.06–0.22)	0.85 (0.70–0.94)	0.08 ± 0.06
RA R	0.60 (0.08–0.25)	0.86 (0.75–0.98)	−0.11 ± 0.06
RA Ac	0.62 (0.07–0.20)	0.88 (0.76–0.97)	−0.19 ± 0.03

Key: EO R external oblique resting stage, EO Ac external oblique active stage, IO R internal oblique resting stage, IO Ac internal oblique active stage, TrA R transverse abdominis resting. TrA Ac transverse abdominis active stage, RA R rectus abdominis resting stage, RA Ac rectus abdominis active stage