Table 1

The modifying effect of pain mechanisms* and pain catastrophising* on the effectiveness of the add-on intervention in improving shoulder disability and strength, and within-group changes and between-group differences in change for each stratum of potential effect modifiers

Within-group change (baseline to week 16)Between-group change (difference in change) Interaction
InterventionControlContrastEffect
Mean(95% CI)Mean(95% CI)Mean(95% CI)(95% CI)
SPADI, 0 (best) to 100 (worst)
 TSP higher −24(−30 to −18)−22(−28 to −16) Embedded Image −1(−10 to 7)−3
(−15 to 8)
 TSP lower −21(−28 to −14)−23(−28 to −18)2(−7 to 10)
 CPM-tolerance higher −26(−32 to −20)−26(−32 to −21)0(−8 to 8)0
(−11 to 11)
 CPM-tolerance lower −17(−23 to −10)−17(−23 to −11)0(−8 to 9)
 CPM-detection higher −21(−27 to −15)−25(−31 to −19)4(−4 to 12)7
(−5 to 18)
 CPM-detection lower −22(−29 to −16)−19(−25 to −14)−3(−11 to 5)
 PPT-deltoid higher −27(−33 to −20)−23(−28 to −17)−4(−12 to 4)−7
(−18 to 4)
 PPT-deltoid lower −20(−26 to −14)−22(−27 to −16)2(−6 to 10)
 PCS higher −14(−22 to −6)−23(−29 to −17)9(−1 to 18)14
(2 to 25)
 PCS lower −31(−35 to −26)−23(−28 to −18)−8(−14 to −1)
Abduction MVC, Nm/kg
 TSP higher 0.04(0.01 to 0.07)0.05(0.02 to 0.08) Embedded Image −0.01(−0.05 to 0.03)0.00
(−0.08 to 0.07)
 TSP lower 0.01(−0.04 to 0.06)0.03(−0.01 to 0.06)−0.02(−0.08 to 0.04)
 CPM-tolerance higher 0.04(0.00 to 0.08)0.03(−0.01 to 0.07)0.01(−0.05 to 0.06)0.03
(−0.04 to 0.11)
 CPM-tolerance lower −0.01(−0.05 to 0.03)0.02(−0.01 to 0.05)−0.03(−0.08 to 0.02)
 CPM-detection higher 0.00(−0.04 to 0.04)0.03(−0.01 to 0.07)−0.03(−0.09 to 0.02)−0.03
(−0.11 to 0.04)
 CPM-detection lower 0.03(0.00 to 0.07)0.02(−0.01 to 0.05)0.01(−0.04 to 0.06)
 PPT-deltoid higher 0.04(0.00 to 0.08)0.03(−0.01 to 0.06)0.01(−0.04 to 0.07)0.04
(−0.03 to 0.11)
 PPT-deltoid lower 0.00(−0.03 to 0.03)0.03(0.00 to 0.06)−0.03(−0.07 to 0.02)
 PCS higher 0.00(−0.04 to 0.05)0.02(−0.02 to 0.06)−0.02(−0.08 to 0.04)−0.01
(−0.07 to 0.06)
 PCS lower 0.05(0.02 to 0.08)0.05(0.02 to 0.08)−0.01(−0.05 to 0.04)
External rotation MVC, Nm/kg
 TSP higher 0.00(−0.01 to 0.02)−0.01(−0.02 to 0.01) Embedded Image 0.01(−0.01 to 0.03)0.00
(−0.02 to 0.03)
 TSP lower 0.01(−0.01 to 0.03)0.01(−0.01 to 0.02)0.00(−0.02 to 0.02)
 CPM-tolerance higher 0.01(0.00 to 0.03)0.01(−0.01 to 0.02)0.00(−0.02 to 0.02)0.00
(−0.03 to 0.02)
 CPM-tolerance lower 0.00(−0.02 to 0.02)0.00(−0.02 to 0.01)0.00(−0.02 to 0.02)
 CPM-detection higher −0.01(−0.02 to 0.00)0.01(−0.01 to 0.02)−0.02(−0.04 to 0.00)−0.04
(−0.06 to −0.01)
 CPM-detection lower 0.02(0.01 to 0.04)0.00(−0.01 to 0.01)0.03(0.01 to 0.05)
 PPT-deltoid higher 0.02(0.00 to 0.04)−0.01(−0.02 to 0.01)0.02(0.00 to 0.04)0.03
(0.00 to 0.06)
 PPT-deltoid lower 0.00(−0.02 to 0.01)0.01(−0.01 to 0.02)−0.01(−0.03 to 0.01)
 PCS higher 0.00(−0.02 to 0.02)0.00(−0.01 to 0.02)0.00(−0.03 to 0.02)−0.01
(−0.04 to 0.02)
 PCS lower 0.01(0.00 to 0.03)0.00(−0.02 to 0.01)0.02(0.00 to 0.03)
  • *Median split cut points: TSP=2.7 points, CPM-tolerance=1.5 kPa, CPM-detection=3.3 kPa, PPT-deltoid=176 kPa, PCS=16 points.

  • CPM-detection, conditioned pain modulation detection threshold; CPM-tolerance, conditioned pain modulation tolerance threshold; MVC, maximum voluntary contraction; PCS, Pain Catastrophizing Scale; PPT-deltoid, pressure pain threshold at the deltoid muscle; SPADI, Shoulder Pain and Disability Index; TSP, Temporal summation of pain.