Table 4.

Predictive factors for disability measured with Oswestry Disability Index in women with persistent pelvic girdle pain at 15 months postpartum

Independent variables	Dependent variable: continues Oswestry Disability Index at 15 months postpartum
	β-Coefficient	95 % CI	t	P
Constant	58.49
Age	−1.36	−2.11 to −0.60	−3.63	<0.0008
Trunk flexor endurancea	−1.23	−1.83 to −0.62	−4.10	<0.0002
Oswestry Disability Indexb	−1.14	−2.04 to −0.24	−2.56	<0.0140
Hip extensor strengthc	−0.05	−0.11 to 0.01	−1.74	<0.0885
Interaction: age and trunk flexor enduranced	0.04	0.02 to 0.06	4.15	<0.0002
Interaction: disability and hip extensor strengthe	0.01	<0.01 to 0.01	3.83	<0.0004

Multiple linear regression analysis with Oswestry Disability Index (ODI) at 15 months postpartum as dependent variable. The independent variables were collected at baseline evaluation 3 months postpartum

Unstandardized β-coefficient, 95 % CI = 95 % confidence interval and P value given for β-coefficients. Adjusted R² was 0.52. n = 50

^aTrunk flexor endurance 0–120 s

^bODI: 0–100 %: high value indicating high disability

^cHip extensor strength measured in Newtons

^dInteraction between age and trunk flexor endurance

^eInteraction between disability measured with the ODI and hip extensor strength