Table 3 Results of the regression of functional ability (walking time, GUG time and WOMAC-PF) on mid-stance VVP* and total muscle strength

Variables‡	Walking time		GUG		WOMAC-PF
Variables‡	b† (SE)	p Value	b (SE)	p Value	b (SE)	p Value
Intercept	86.93		11.33		30.90
Mid-stance VVP	7.40 (2.16)	0.001	1.03 (0.47	0.031	2.29 (1.01)	0.028
Muscle strength	−52.17 (7.48)	0.000	−10.00 (1.61)	0.000	−15.83 (3.51)	0.000
Mid-stance VVP× muscle strength	−5.74 (4.52)	0.210	−0.36 (0.97)	0.716	−0.1.30 (2.12)	0.543
Mid-stance VVP diff§	3.96 (1.53)	0.012	0.87 (0.33)	0.011	−1.46 (0.72)	0.851
	R2 = 0.54 F = 16.66 <0.001		R2 = 0.45 F = 11.57 <0.001		R2 = 0.36 F = 8.03 <0.001

*Mid-stance VVP as the varus–valgus angle of the OA knee in mid-stance of the gait cycle.
†b = unstandardised regression coefficient.
‡Variables centred around the mean.
§Mid-stance VVP diff = the difference between left and right mid-stance VVP data.
GUG, Get Up and Go test; PF, physical function.