Table 2 Subgroup descriptions and post hoc analysis

Percentage of total cohort (n = 266)

50% (n = 133)

27.4% (n = 73)

15.4% (n = 41)

7.1% (n = 19)

 Percentage (and number) of people with LBP in each sub group cluster

26.3% (35)

71.2% (52)

82.9% (34)

100.0% (19)

 Posterior probability of belonging to each cluster

0.95 ± 0.10

0.91 ± 0.13

0.97 ± 0.08

0.97 ± 0.11

 Age

36.5 ± 13.6 ³

37.5 ± 13.7

42.1 ± 14.8

38.1 ± 13.5

Yes

 Sex (female)

60.9%

57.5%

56.1%

47.3%

No

 Pain intensity using numerical rating scale (0–10 scale)

5.2 ± 1.4

5.1 ± 1.3

5.6 ± 1.8

5.3 ± 1.5

No

 ‘Flexion aggravates, Extension eases’ pain score (0–48 scale) ^a

12.8 ± 7.3 ⁴

14.5 ± 8.0 ⁴

16.4 ± 8.8 ⁴

22.7 ± 8.4 ^1,2,3

Yes

 Activity limitation (0–100 scale)

31 ± 17 ⁴

38 ± 20

42 ± 22

48 ± 26 ¹

Yes

 Percentage of LBP people with leg pain ^b

36.3% ^2,4

52.0% ^1,4

21.8% ⁴

76.5% ^1,2,3

Yes

 Trunk Peak ROM (^o)

111 ± 12 ^2,3,4

97 ± 17 ^1,3,4

89 ± 16 ^1,2,4

77 ± 20 ^1,2,3

Yes

 Lumbar Peak ROM (^o)

51 ± 9 ³

54 ± 10 ^3,4

30 ± 8.5 ^1,2,4

47 ± 14 ^2,3

Yes

 Pelvic ROM (^o)

60 ± 11 ^2,4

44 ± 5 ^1,4

59 ± 15 ^2,4

31 ± 11 ^1,2,3

Yes

 Percentage of lumbar contribution to trunk flexion (%)

47 ± 7 ^2,3,4

57 ± 10 ^1,3

35 ± 9 ^1,2,4

60 ± 9 ^1,3

Yes

 Flexion relaxation response

0.00 ± 0.00 ^2,3,4

0.04 ± 0.05 ^3,4

0.48 ± 0.50 ^1,2

0.72 ± 0.55 ^1,2

Yes

 Duration of trunk flexion (sec)

2.31 ± 0.63 ^2,3,4

3.11 ± 1.11 ¹

2.87 ± 0.70 ¹

4.10 ± 1.83 ¹

Yes

 Pelvic time-lag at start of movement (sec)^c

+ 0.17 ± 0.14 ^2,4

+ 0.42 ± 0.31 ^1,3

+ 0.13 ± 0.24 ^2,4

+ 1.10 ± 1.34 ^1,3

Yes

 Pelvic time-lag at 20^o of movement (sec)^c

+ 0.22 ± 0.30 ^2,4

+ 0.86 ± 0.53 ^1,4

- 0.55 ± 0.8 ⁴

+ 2.04 ± 1.74 ^1,2,3

Yes