Table 2 The differences in the CSA and FI % of the paraspinal muscles among the different age strata and gender in the LDD and asymptomatic groups

Men

Multifidus CSA (cm²)

21.33 ± 3.55

21.13 ± 3.08

19.64 ± 3.75

0.015*

20.31 ± 2.91

20.22 ± 2.77

18.73 ± 3.34

0.019*

Erector spinae CSA (cm²)

37.23 (33.66 ~ 40.59)

35.51 (29.89 ~ 39.78)

30.11 (25.7 ~ 35.02)

 < 0.001*

34.06(29.76 ~ 37.28)

33.46(28.96 ~ 38.6)

28.59(25.77 ~ 35.92)

0.012*

Psoas CSA (cm²)

36.63 ± 6.48

31.57 ± 5.48

25.46 ± 5.62

 < 0.001*

33.39(30.34 ~ 39.4)

30.64(26.45 ~ 36.65)

26.04(23.54 ~ 30.05)

 < 0.001*

Multifidus FI%

19.11 (15.99 ~ 22.24)

21.63 (16.65 ~ 28.44)

31.74 (27.39 ~ 36.19)

 < 0.001*

13.85(12.25 ~ 17.07)

17.76(13.16 ~ 21.26)

26.68(23.78 ~ 33.83)

 < 0.001*

Erector spinae FI%

13.69 (11.57 ~ 16.1)

16.69 (12.05 ~ 22.75)

23.09 (18.27 ~ 28.95)

 < 0.001*

10.07(7.57 ~ 12.66)

12.58(10.81 ~ 15.88)

19.96(16.43 ~ 23.61)

 < 0.001*

Women

Multifidus CSA (cm²)

17.53 ± 3.20

17.05 ± 2.91

15.98 ± 2.76

0.009*

16.78 ± 2.76

16.93 ± 2.92

16.77 ± 2.80

0.944

Erector spinae CSA (cm²)

24.74 (23.15 ~ 29.87)

27.00 (22.36 ~ 31.55)

25.71 (22.36 ~ 29.57)

0.162

23.77 (20.9 ~ 28.04)

24.60 (22.89 ~ 27.65)

25.59 (21.13 ~ 28.85)

0.313

Psoas CSA (cm²)

20.16 (17.32 ~ 22.85)

19.98 (16.85 ~ 21.69)

16.53 (14.04 ~ 18.65)

 < 0.001*

19.88 (17.46 ~ 22.79)

18.35 (16.49 ~ 20.57)

16.04 (13.81 ~ 19.11)

 < 0.001*

Multifidus FI%

25.35 (23.1 ~ 29.76)

28.98 (23.26 ~ 34.58)

36.66 (32.02 ~ 41.66)

 < 0.001*

18.07(16.09 ~ 20.97)

22.68(19.84 ~ 26.93)

31.59(29.01 ~ 35.55)

 < 0.001*

Erector spinae FI%

15.8 (12.44 ~ 19.27)

21.25 (16.94 ~ 26.66)

28.97 (23.22 ~ 33.06)

 < 0.001*

11.8(9.62 ~ 14.02)

15.46(13.27 ~ 19.14)

23.72(19.27 ~ 28.94)

 < 0.001*