Table 2. Results of multivariate logistic regression analysis.

		Explanatory variables, P-value
		Time of exercise	Grade in school	Sex	Mode of going to school
Objective variables
	Scoliosis	n.s.	0.001	n.s.	n.s.
	Stand flexion	< 0.001	< 0.001	< 0.001	n.s.
	Full squat	n.s.	< 0.001	< 0.001	n.s.
	One-leg stand	< 0.001	< 0.001	< 0.001	< 0.001
	Genu valgum	n.s.	n.s.	n.s.	n.s.
	Genu varum	n.s.	< 0.001	0.01	n.s.
	Flat feet	n.s.	< 0.001	< 0.001	n.s.
	Fracture or dislocation	< 0.001	< 0.001	< 0.001	n.s.
	Osgood disease	< 0.001	< 0.001	< 0.001	n.s.
	Baseball elbow	< 0.001	< 0.001	< 0.001	n.s.
	Spondylolysis	0.021	0.009	n.s.	n.s.

n.s.: not significant.