Table 3.

Comparison of motor performance, stability and stiffness parameters between the pre- and post-treatment condition in the WBV and sham group (young adults and elderly).

	Motor performance, stability and stiffness	WBV group		Sham group		Group X treatment interaction
	Variables	Before	After	Before	After	P-values
Young adults	Swing phase duration (s)	0.12 ± 0.02	0.13 ± 0.03	0.14 ± 0.04	0.14 ± 0.04	NS
	Step length (cm)	67.94 ± 6.43	67.89 ± 6.74	70.32 ± 8.61	70.68 ± 7.45	NS
	AP COM velocity at FC (m/s)	0.96 ± 0.01	0.98 ± 0.09	1.01 ± 0.12	1.02 ± 0.11	NS
	Step width (cm)	17.11 ± 4.03	17.07 ± 4.09	18.12 ± 4.57	17.52 ± 4.19	NS
	ML COM position at FC (cm)	3.56 ± 2.80	4.52 ± 2.11**	3.85 ± 2.27	3.93 ± 2.31	0.03
	ML COM velocity at FC (m/s)	−0.14 ± 0.05	−0.12 ± 0.04**	−0.15 ± 0.03	−0.14 ± 0.03	0.04
	Margin of stability (cm)	4.74 ± 3.43	5.76 ± 2.56*	5.79 ± 2.65	5.77 ± 2.48	0.02
	Stiffness	835.10 ± 355.40	975.62 ± 290.11*	973.32 ± 293.83	972.98 ± 328.87	0.04
Elderly	Swing phase duration (s)	0.14 ± 0.02	0.14 ± 0.04	0.14 ± 0.02	0.14 ± 0.04	NS
	Step length (cm)	52.74 ± 10.19	53.89 ± 8.35	52.74 ± 10.32	54.39 ± 9.20	NS
	AP COM velocity at FC (m/s)	0.74 ± 0.17	0.78 ± 0.11	0.76 ± 0.14	0.79 ± 0.11	NS
	Step width (cm)	16.84 ± 2.44	17.17 ± 2.77	17.49 ± 4.42	18.10 ± 4.96	NS
	ML COM position at FC (cm)	6.32 ± 5.19	5.98 ± 4.84	6.38 ± 6.34	6.11 ± 5.66	NS
	ML COM velocity at HC (m/s)	−0.13 ± 0.03	−0.14 ± 0.03	−0.14 ± 0.04	−0.15 ± 0.05	NS
	Margin of stability (cm)	5.98 ± 1.72	5.18 ± 2.21	6.38 ± 2.24	5.59 ± 2.58	NS
	Stiffness	1061.90 ± 145.99	1006.45 ± 221.21	1208.88 ± 389.14	1208.33 ± 508.51	NS

Reported values are means ± standard deviation. COM, center of mass; COP, center of pressure; AP, anteroposterior; ML, mediolateral; FC, foot contact; NS, non-significant interaction.

^{*, **, ***}Significant difference between the pre and post-treatment condition as revealed with the Tukey post-hoc test, with P < 0.05, P < 0.01, and P < 0.001, respectively.