Table 3 The differences in the CSA and FI % of the paraspinal muscles between LDD and asymptomatic groups in different age strata and gender

Men

Multifidus CSA (cm²)

21.33 ± 3.55

20.31 ± 2.91

0.126

21.13 ± 3.08

20.22 ± 2.77

0.119

19.64 ± 3.75

18.73 ± 3.34

0.189

Erector spinae CSA (cm²)

37.23 (33.66 ~ 40.59)

34.06 (29.76 ~ 37.28)

0.051

35.88 ± 7.96

33.77 ± 6.89

0.156

30.11 (25.70 ~ 35.02)

28.59 (25.77 ~ 35.92)

0.760

Psoas CSA (cm²)

35.55 (32.49 ~ 40.10)

33.39 (30.34 ~ 3940)

0.083

31.57 ± 5.48

30.93 ± 6.04

0.577

25.46 ± 5.62

25.99 ± 5.42

0.618

Multifidus FI%

19.21 ± 5.40

14.54 ± 3.41

 < 0.001*

22.49 ± 7.83

17.42 ± 4.82

 < 0.001*

31.74 (27.39 ~ 36.19)

26.68 (23.78 ~ 33.83)

0.008*

Erector spinae FI%

13.69 (11.57 ~ 16.10)

10.10 (7.57 ~ 12.66)

 < 0.001*

16.69 (12.05 ~ 22.75)

12.58 (10.81 ~ 15.88)

 < 0.001*

23.09 (18.27 ~ 28.95)

19.96 (16.43 ~ 23.61)

0.009*

Women

Multifidus CSA (cm²)

17.53 ± 3.20

16.78 ± 2.76

0.247

17.05 ± 2.91

16.93 ± 2.92

0.836

15.98 ± 2.76

16.77 ± 2.80

0.098

Erector spinae CSA (cm²)

24.74 (23.15 ~ 29.87)

23.77 (20.90 ~ 28.04)

0.147

27.00 (22.36 ~ 31.55)

24.60 (22.89 ~ 27.65)

0.097

25.97 ± 5.21

25.43 ± 5.68

0.549

Psoas CSA (cm²)

20.16 (17.32 ~ 22.85)

19.88 (17.46 ~ 22.79)

0.864

19.98 (16.85 ~ 21.69)

18.35 (16.49 ~ 20.57)

0.239

16.53 (14.04 ~ 18.65)

16.04 (13.81 ~ 19.11)

0.772

Multifidus FI%

25.35 (23.10 ~ 29.76)

18.07 (16.09 ~ 20.97)

 < 0.001*

28.65 ± 6.91

23.28 ± 5.00

 < 0.001*

36.66 (32.02 ~ 41.66)

31.59 (29.01 ~ 35.55)

 < 0.001*

Erector spinae FI%

15.80 (12.44 ~ 19.27)

11.80 (9.62 ~ 14.02)

 < 0.001*

21.25 (16.94 ~ 26.66)

15.46 (13.27 ~ 19.14)

 < 0.001*

28.66 ± 7.16

24.23 ± 5.80

 < 0.001*