Fig. 6

Intra-cluster similarity values of the trunk muscle synergies (C1 to C5) between the non-CLBP and CLBP groups. The intra-cluster similarity of the temporal pattern components in C2, C3 and C5 were significantly higher in the CLBP group than in the non-CLBP group (C2: p = 0.000009, d = 1.07; C3: p = 0.0000006, d = 0.70; C5: p = 0.047, d = 0.30). There was no significant difference in C1 and C4 between the groups (C1: p = 0.152; C4: p = 0.385)