Table 6 Factor loads of baseline scores, follow-up scores and score differences (difference of follow-up – baseline score)

 Physical functioning (PF)

0.16

0.73

0.19

0.81

0.18

0.65

 Role physical (RP)

0.20

0.56

0.14

0.76

0.19

0.54

 Bodily pain (BP)

0.24

0.68

0.31

0.70

0.35

0.62

 General health (GH)

0.57

0.27

0.60

0.38

0.53

0.24

 Vitality (VT)

0.73

0.27

0.72

0.34

0.50

0.52

 Social functioning (SF)

0.63

0.44

0.66

0.21

0.59

0.13

 Role emotional (RE)

0.57

0.33

0.48

0.44

0.43

0.30

 Mental health (MH)

0.84

0.21

0.86

0.17

0.71

0.22

 Pain severity (PS)

0.27

0.63

0.39

0.68

0.15

0.76

 Interference (INT)

0.57

0.63

0.54

0.63

0.31

0.67

 Negative mood (NM)

0.80

0.24

0.81

0.22

0.69

0.29

 Life control (LIF)

0.68

0.03

0.75

0.15

0.65

0.27

 Social and away from home activities (SOC)

0.43

0.25

0.40

0.40

0.25

0.33

 Somatization (SOM)

0.60

0.23

0.72

0.34

0.51

0.30

 Anxiety (ANX)

0.81

0.05

0.84

0.13

0.75

−0.08

 Depression (DEP)

0.89

0.16

0.87

0.25

0.82

0.12

 Anger-hostility (AH)

0.80

0.04

0.78

0.11

0.71

−0.03

ODI

0.36

0.71

0.40

0.78

0.20

0.68

Back Performance Scale

0.01

0.69

0.11

0.68

−0.08

0.44

6 Minute Walking Distance (m)

0.00

0.79

0.03

0.71

0.01

0.52

Explained variance (%)

43.0

12.3

48.9

11.9

33.5

10.5

Total explained variance (%)

55.3

60.9

44.0