Table 3.

Comparisons for the thickness and activity of the lumbar multifidus and lateral abdominal wall muscles between different volitional preemptive abdominal contraction (VPAC) strategies.

Muscle		AE versus AD			AE versus NB			AD versus NB
		∆	95% CI	p	∆	95% CI	p	∆	95% CI	p
Muscle thickness
MF 1	Overall	0.7	−0.2, 1.7	0.193	2.0	1.2, 2.7	<0.001	1.2	0.6, 1.9	<0.001
TrA 2	LYI	−1.5	−2.0, −1.0	<0.001	0.4	−0.1, 0.9	0.091	2.0	1.5, 2.4	<0.001
	QTS	−1.7	−2.4, −1.1	<0.001	−0.4	−0.8, 0.1	0.203	1.4	0.9, 1.9	<0.001
	SLS	−1.9	−2.7, −1.1	<0.001	−0.4	−1.0, 0.1	0.178	1.5	1.0, 1.9	<0.001
IO	Overall	−2.0	−2.9, −1.1	<0.001	−0.2	−0.9, 0.5	>0.999	1.8	1.3, 2.3	<0.001
EO	Overall	−1.3	−1.9, −0.8	<0.001	−0.8	−1.2, −0.4	<0.001	0.5	0.03, 1.0	0.036
Muscle activity
MF	Overall	7.3	−8.5, 23.0	0.754	18.1	2.9, 33.2	0.015	10.8	4.0, 17.7	0.001
IO/TrA	Overall	−61.9	−101.9, −21.8	0.002	29.5	9.0, 50.0	0.003	91.3	46.5, 136.1	<0.001
EO	LYI	−6.6	−13.9, 0.74	0.090	11.1	5.5, 16.8	<0.001	17.7	8.5, 27.0	<0.001
	QTS	−0.9	−10.9, 9.2	>0.999	21.9	8.1, 35.6	0.001	22.7	7.7, 37.8	0.002
	SLS	−0.9	−12.1, 10.3	>0.999	15.4	3.7, 27.0	0.007	16.3	0.1, 32.4	0.048

Abbreviation: MF = lumbar multifidus; TrA = transverse abdominis; EO = external abdominal oblique; IO = internal abdominal oblique; LYI = lying; QTS = quiet standing; SLS = single leg standing; AE = abdominal expansion strategy; AD = abdominal drawing-in strategy; NB = natural breathing strategy; CI = confidence interval; ∆ = mean difference. ¹ The interaction effect was not significant; therefore, the VPAC effect was analyzed regardless of the position. ² The interaction effect was significant; therefore, the VPAC effect was analyzed at each position.