Table 1 Peak joint angle parameters depending on the frequency of the VSS in the elderly

Hip Joint Angle

HA_1

66.6 ± 3.8

67.2 ± 3.8

67.4 ± 3.3

95% CI

[− 0.26, 2.64]

[−0.82, 2.07]

[− 0.88, 1.74]

t-value*

1.85

0.98

0.74

p value*

0.098

0.353

0.480

HA_2

7.3 ± 3.5

5.9 ± 4.8

6.3 ± 5.1

95% CI

[−5.81, 1.05]

[−2.41, 0.39]

[−3.28, 0.39]

t-value*

−1.57

−1.63

− 1.79

p value*

0.151

0.137

0.108

Knee Joint Angle

KA_1

*91.0 ± 7.1

*92.0 ± 8.5

92.9 ± 8.5

95% CI

[0.89, 6.34]

[0.88, 5.34]

[−1.21, 4.70]

t-value*

3.022

2.34

1.34

p value*

0.015

0.044

0.214

KA_2

68.3 ± 2.2

69.6 ± 3.3

69.3 ± 3.6

KA_3

*21.3 ± 4.6

*20.6 ± 5.6

*20.4 ± 5.7

95% CI

[−5.33, −1.06]

[−4.28, −0.71]

[−4.19, −0.32]

t-value*

−3.39

−3.16

−2.64

p value*

0.008

0.012

0.027

Ankle Joint Angle

AA_1

*15.3 ± 3.4

*15.4 ± 3.7

*15.2 ± 3.6

95% CI

[−4.62, −0.75]

[−5.51, − 0.02]

[− 5.11, − 0.03]

t-value*

−3.14

−2.28

− 2.29

p value*

0.012

0.049

0.048

AA_2

28.3 ± 3.2

28.3 ± 3.1

28.0 ± 2.8

AA_3

18.3 ± 5.1

19.3 ± 4.7^c

18.1 ± 5.3^b

95% CI^a,b,c

–

[0.03, 2.30]

[0.03, 2.30]

t-value^a,b,c

–

2.32

2.32

p value^a,b,c

–

0.045^c

0.045^b

AA_4

*26.4 ± 2.4

*25.6 ± 2.4

25.0 ± 2.4^a

95% CI*

[−3.97, −0.50]

[2.95, −0.04]

[−2.82, 0.97]

t-value*

−2.91

−2.33

−1.10

p value*

0.017

0.045

0.298

95% CI^a,b,c

[0.58, 2.03]

–

[0.58, 2.03]

t-value^a,b,c

4.07

–

4.07

p value^a,b,c

0.003^c

–

0.003^a