Table 4 Joint power parameters depending on the frequency of the VSS in the elderly

Hip Joint Power

HPP_1

0.786 ± 0.584^bc

*0.851 ± 0.595^a

*0.837 ± 0.604^a

Z-value*

−1.525

−5.782

−4.846

p value*

0.127

p < 0.001

p < 0.001

Z-value^a,b,c

−4.710

−0.868

−6.463

p value^a,b,c

p < 0.001^b

0.385^c

p < 0.001^a

HPP_2

0.323 ± 0.225^c

0.328 ± 0.219^c

*0.395 ± 0.195^ab

95% CI*

[−0.08, 0.03]

[− 0.09, 0.02]

[− 0.15, − 0.05]

t-value*

−1.23

−1.36

−4.91

p value*

0.264

0.222

0.003

95% CI^a,b,c

[−0.02, 0.01]

[−0.09, − 0.04]

[−0.11, − 0.04]

t-value^a,b,c

−0.75

−6.36

−4.93

p value^a,b,c

0.480^b

0.001^c

0.003^a

Knee Joint Power

KNP

*-0.141 ± 0.091^c

*-0.141 ± 0.092^c

−0.154 ± 0.102^ab

Z-value*

−2.688

−2.427

−1.344

p value*

0.007

0.015

0.179

Z-value^a,b,c

−1.792

−2.728

−3.584

p value^a,b,c

0.073^b

0.006^c

p < 0.001^a

KPP

0.609 ± 0.483

*0.692 ± 0.517

*0.705 ± 0.489

Z-value*

−0.198

−3.876

− 3.832

p value*

0.843

p < 0.001

p < 0.001

Ankle Joint Power

ANP

*-0.214 ± 0.138

*-0.222 ± 0.137^c

*-0.197 ± 0.126^b

95% CI*

[0.05, 0.13]

[0.06, 0.11]

[0.04, 0.08]

t-value*

4.90

7.42

6.15

p value*

p < 0.001

p < 0.001

p < 0.001

95% CI^a,b,c

–

[−0.04, −0.01]

[−0.04, − 0.01]

t-value^a,b,c

–

−3.35

−3.35

p value^a,b,c

–

0.004^c

0.004^b

APP

1.519 ± 1.021

1.410 ± 1.005^c

1.598 ± 0.934^b

95% CI^a,b,c

–

[−0.14, −0.02]

[−0.14, − 0.02]

t-value^a,b,c

–

−2.70

−2.70

p value^a,b,c

–

0.019^c

0.019^b