Table 2 Analyses of correlations between the changes in pain disability and the independent variables (n = 56)

Age (years)

0.16 (0.23)

0.05 (0.74)

−0.02 (0.88)

0.17 (0.21)

Symptom duration (years)

0.03 (0.81)

−0.12 (0.37)

0.12 (0.37)

0.17 (0.22)

Pain intensity (0–100)

−0.26 (0.054) ^a

−0.19 (0.17) ^a

−0.04 (0.75)

−0.06 (0.67) ^a

PDI total (0–70)

−0.34 (0.01)

−0.25 (0.066) ^a

−0.25 (0.067) ^a

−0.18 (0.19) ^a

PDI recreation (0–10)

-

−0.30 (0.027)

-

-

PDI social (0–10)

-

-

−0.45 (<0.001)

-

PDI occupation (0–10)

-

-

-

−0.37 (0.005)

LTPAI (hours)

0.19 (0.17) ^a

0.09 (0.54)

0.04 (0.75)

−0.01 (0.99)

Knee-extension force (N)

−0.13 (0.32)

0.04 (0.75)

−0.07 (0.61)

−0.15 (0.28)

Hand-grip force (N)

−0.05 (0.70)

0.11 (0.43)

−0.01 (0.99)

−0.061 (0.65)

FABQ_physical (0–24)

0.01 (0.93)

0.04 (0.75)

−0.18 (0.19) ^a

0.01 (0.94)

Δ Pain intensity (0–100)

0.36 (0.008)

0.35 (0.008)

0.18 (0.19) ^a

0.15 (0.26)

Δ LTPAI (hours)

−0.28 (0.037)

−0.11 (0.43)

−0.27 (0.049)

−0.05 (0.72)

Δ Knee-extension force (N)

−0.32 (0.019)

−0.16 (0.25)

−0.12 (0.39)

−0.23 (0.09)

Δ Hand-grip force (N)

−0.23 (0.10) ^a

−0.14 (0.33)

−0.25 (0.08)

−0.32 (0.023)

Δ FABQ_physical (0–24)

0.36 (0.007)

0.44 (0.001)

0.34 (0.012)

0.17 (0.23)