Table 1 Demographic and clinical characteristics of the no-LBP and CLBP groups, by gender

N (%)

17 (40.5)

25 (59.5)

11 (37.9)

18 (62.1)

Age (years)

35.8 (14.0)

36.2 (12.0)

-0.3 (-8.5,7.8)

36.2 (15.4)

34.7 (14.3)

1.5 (-10.1, 13.0)

-0.4 (-11.9, 11.2)

1.4 (-6.7, 9.6)

Height (cm)

179.3 (7.1)

163.4 (7.7)

15.9 (11.6, 20.6)*

177.6 (4.4)

165.1 (6.0)

12.5 (8.2, 16.8)*

1.7 (-3.2, 6.6)

-1.7 (-6.1, 2.7)

Mass (kg)

79.1 (13.1)

61.8 (10.4)

17.3 (10.0, 24.6)*

81.3 (8.1)

66.3 (9.1)

15.0 (8.1, 21.9)*

-2.2 (-11.3, 6.9)

-4.5 (-10.7, 1.6)

BMI (kg/m²)

24.5 (3.1)

23.1 (3.0)

1.4 (-0.5, 3.4)

25.8 (2.7)

24.3 (3.0)

1.5 (-0.8, 3.8)

-1.3 (-3.6, 1.1)

-1.2 (-3.1, 0.6)

Hip girth (cm)

98.4 (7.2)

96.1 (9.3)

2.3 (-3.1, 7.7)

101.3 (6.2)

100.4 (7.1)

0.9 (-4.5, 6.2)

-2.8 (-8.2, 2.6)

-4.3 (-9.5, 1.0)

Waist girth (cm)

84.4 (8.6)

73.2 (10.3)

11.2 (5.2, 17.4)*

86.6 (8.5)

76.2 (9.3)

10.4 (3.3, 17.4)*

-2.3 (-9.0, 4.6)

-3.1 (-9.3, 3.1)

Back muscle endurance (sec) [range 0-360]

188.8 (49.9)

216.4 (92.6)

-27.6 (-77.4, 22.2)

165.3 (51.9)

148.6 (72.9)

16.7 (-35.1, 68.4)

23.5 (-16.8, 63.8)

67.8 (14.7, 120.8)*

DASS-21 depression [range 0-21]

2.1 (3.8)

2.8 (5.6)

-0.7 (-3.9, 2.4)

4.2 (6.7)

2.1 (2.4)

2.2 (-1.4, 5.7)

-2.2 (-6.3, 1.9)

0.7 (-2.1, 3.6)

DASS-21 anxiety [range 0-21]

1.8 (2.3)

2.5 (4.6)

-0.7 (-3.2, 1.7)

2.9 (2.7)

3.1 (3.4)

-0.2 (-2.7, 2.3)

-1.1 (-3.1, 0.8)

-0.6 (-3.2, 1.9)

DASS-21 stress [range 0-21]

8.7 (7.4)

10.1 (7.0)

-1.4 (-5.9, 3.2)

6.5 (6.2)

8.8 (4.9)

-2.2 (-6.5, 2.0)

2.2 (-3.4, 7.7)

1.3 (-2.6, 5.2)

Days/week of vigorous physical activity (days) [range 0-7]

4.1 (1.9)

3.4 (3.4)

0.8 (-0.3, 1.8)

3.6 (2.3)

3.1 (1.4)

0.4 (-1.0, 1.8)

0.6 (-1.1, 2.2)

0.2 (-0.7, 1.2)

ODI (%)

16.2 (8.7)

15.4 (9.1)

0.7 (-6.3, 7.8)

LBP history (yrs)

13.3 (10.4)

11.6 (9.9)

1.8 (-6.1, 9.7)

Intensity of LBP in last week; median (IQR)

4 (2)

5 (3)

Episodes LBP last year; n (%)

1-3

0 (0)

0 (0)

4-10

3 (27.3)

8 (44.4)

> 10

8 (72.7)

10 (55.6)

Work days missed with last year; n (%)

0

9 (81.8)

12 (66.7)

1-2

2 (18.2)

3 (16.7)

3-7

3 (16.7)

Interference with normal activities; % reporting 'yes'

5 (45.5)

8 (44.4)

Interference with recreational activities; % reporting 'yes'

6 (54.5)

8 (44.4)

Currently taking analgesic medication; % reporting 'yes'

8 (19.0)

19 (45.2)

8 (27.6)

12 (41.4)

Currently taking NSAID medication; % reporting 'yes'

0 (0)

1 (2.4)

2 (6.9)

2 (6.9)

PA L3 BMC (g)

20.89 (3.39)

16.72 (3.24)

4.17 (2.05, 6.28)*

20.03 (1.93)

16.46 (3.55)

3.56 (1.17, 5.96)*

0.86 (-1.46, 3.18)

0.26 (-1.87, 2.38)

PA L3 aBMD (g/cm²)

1.13 (0.13)

1.08 (0.14)

0.48 (-0.04, 0.14)

1.11 (0.11)

1.10 (0.19)

0.02 (-0.12, 0.15)

0.02 (-0.08, 0.12)

-0.01 (-0.12, 0.09)

PA total spine BMC (g)

79.07 (12.33)

61.30 (13.05)

17.77 (9.66, 25.88)*

75.79 (8.39)

63.50 (13.98)

12.30 (2.70, 21.88)*

3.28 (-5.46, 12.01)

-2.20 (-10.59, 6.19)

PA total spine aBMD (g/cm²)

1.15 (0.12)

1.04 (0.14)

0.06 (-0.02, 0.15)

1.08 (0.10)

1.06 (0.18)

0.02 (-0.11, 0.14)

0.03 (-0.06, 0.12)

-0.02 (-0.12, 0.08)

PA total spine T-score

0.08 (1.28)

-0.06 (1.27)

0.14 (-0.75, 1.03)

-0.08 (0.99)

0.32 (1.63)

-0.40 (-1.66, 0.86)

0.15 (-0.90, 1.21)

-0.38 (-1.35, 0.58)

Lateral L3 BMC (g)

9.42 (1.89)

7.80 (1.74)

1.62 (0.45, 2.79)*

8.71 (1.54)

8.36 (1.64)

0.35 (-0.93, 1.62)

0.72 (-0.69, 2.12)

-0.56 (-1.66, 0.54)

Lateral L3 aBMD (g/cm²)

0.82 (0.13)

0.77 (0.11)

0.06 (-0.02, 0.14)

0.74 (0.12)

0.78 (0.10)

-0.04 (-0.12, 0.04)

0.08 (-0.02, 0.18)

-0.02 (-0.08, 0.05)

Lateral L3 ap.vBMD (g/cm³)

0.21 (0.03)

0.22 (0.03)

-0.01 (-0.03, 0.01)

0.20 (0.03)

0.23 (0.02)

-0.03 (-0.06, -0.01)

0.02 (-0.01, 0.04)

-0.01 (-0.02, 0.01)