Table 1 Average difference (RMSE) of joint position between APAS and Kinect systems measured in cm. Note: the z-axis is the anterior-posterior displacement; the y-axis is the vertical displacement; and the x-axis is mediolateral displacement

1

0.53

0.55

1.54

0.55

0.61

1.88

0.79

0.68

1.86

0.76

0.44

1.82

0.84

0.85

1.79

0.63

0.73

1.80

2

0.54

0.85

2.30

0.56

0.96

2.88

0.63

0.63

1.22

0.64

0.45

0.81

0.52

0.73

1.19

0.42

0.72

0.97

3

0.67

0.60

1.47

0.56

0.91

1.43

0.79

0.53

1.53

0.68

0.43

0.82

0.61

0.68

1.06

0.60

0.81

1.36

4

0.52

0.73

2.47

0.56

0.64

2.24

0.49

0.65

3.11

0.40

0.43

1.35

0.48

0.53

1.38

0.65

0.67

1.31

5

0.85

0.79

2.20

0.82

0.56

1.18

0.29

0.57

0.61

0.41

0.78

2.34

0.89

1.58

3.01

0.84

1.60

2.54

6

0.94

0.71

1.02

0.85

0.83

2.30

1.43

0.89

1.70

1.29

0.63

1.80

1.27

1.40

2.22

1.10

1.21

1.78

7

0.43

0.55

0.89

0.45

0.55

0.83

0.57

0.51

0.53

0.47

0.51

0.58

0.45

1.11

0.77

0.47

0.88

0.89

8

0.65

1.13

2.72

0.57

0.79

2.64

0.46

0.49

1.24

0.46

0.49

1.24

0.54

0.72

1.50

0.49

0.79

1.35