Table 2 Description of feature extraction

1

27

Mean values of the angle, force and moment of the ankle, hip and knee joints in the frontal, transverse and sagittal planes

2

27

STD of the angle, force and moment of the ankle, hip and knee joints in the frontal, transverse and sagittal planes

3

27

Skewness of the angle, force and moment of the ankle, hip and knee joints in the frontal, transverse and sagittal planes

4

27

Kurtosis of the angle, force and moment of the ankle, hip and knee joints in the frontal, transverse and sagittal planes

5

81

RQA (including RR, DET and ENTR) of the angle, force and moment of the ankle, hip and knee joints in the frontal, transverse and sagittal planes

6

27

FuzzyEn of the angle, force and moment of the ankle, hip and knee joints in the frontal, transverse and sagittal planes

7

27

TKE of the angle, force and moment of the ankle, hip and knee joints in the frontal, transverse and sagittal planes

8

243

Total number of features

9

38

Statistically significant features (shown in Table 3)

10

16

Optimal feature set containing: F1, F2, F10, F19, F24, F29, F30, F61, F67, F96, F149, F176, F191, F207, F217, F227 (shown in Table 3)