Table 3 Average EMG amplitude during the modified Biering Sorensen’s test, normalized to the MVC reference. All values are expressed by mean difference (%), confidence intervals and p-values (HC = healthy controls; RLBP = recurrent low back pain; ncCLBP = non-continuous chronic low back pain; cCLBP = continuous chronic low back pain; LD = latissimus dorsi muscle; GM = gluteus maximus muscle; ES = upper lumbar erector spinae muscle; MF = multifidus muscle)
Concentric phase | Holding phase | Eccentric phase | |||||
|---|---|---|---|---|---|---|---|
Estimates [CI] | p-value | Estimates [CI] | p-value | Estimates [CI] | p-value | ||
LD | ∆HC-RLBP | -0.070 [-1.429;1.290] | 1.000 | -0.070 [-1.429;1.290] | 1.000 | -0.064 [-1.424;1.296] | 1.000 |
∆HC-ncCLBP | -1.011 [-2.565;0.544] | 0.492 | -0.999 [-2.553;0.556] | 0.513 | -0.828 [-2.383;0.726] | 0.916 | |
∆HC-cCLBP | -0.785 [-2.280;0.710] | 0.953 | -0.832 [-2.327;0.663] | 0.813 | -0.928 [-2.423;0.567] | 0.579 | |
∆RLBP-ncCLBP | -0.941 [-2.468;0.586] | 0.594 | -0.929 [-2.456;0.598] | 0.619 | -0.764 [-2.291;0.763] | 1.000 | |
∆RLBP-cCLBP | -0.715 [-2.182;0.752] | 1.000 | -0.762 [-2.229;0.704] | 0.977 | -0.864 [-2.331;0.603] | 0.687 | |
∆NcCLBP-cCLBP | 0.226 [-1.422;1.875] | 1.000 | 0.167 [-1.482;1.816] | 1.000 | -0.100 [-1.748;1.549] | 1.000 | |
GM | ∆HC-RLBP | -0.036 [-1.779;1.706] | 1.000 | -0.034 [-1.777;1.708] | 1.000 | -0.023 [-1.766;1.719] | 1.000 |
∆HC-ncCLBP | -0.217 [-2.203;1.768] | 1.000 | -0.318 [-2.303;1.668] | 1.000 | -0.183 [-2.169;1.802] | 1.000 | |
∆HC-cCLBP | -1.240 [-3.149;0.670] | 0.497 | -1.739 [-3.649;0.170] | 0.095 | -0.837 [-2.746;1.073] | 1.000 | |
∆RLBP-ncCLBP | -0.181 [-2.137;1.775] | 1.000 | -0.283 [-2.239;1.672] | 1.000 | -0.160 [-2.116;1.796] | 1.000 | |
∆RLBP-cCLBP | -1.203 [-3.082;0.675] | 0.522 | -1.705 [-3.584;0.173] | 0.097 | -0.814 [-2.296;1.065] | 1.000 | |
∆NcCLBP-cCLBP | -1.022 [-3.128;1.084] | 1.000 | -1.422 [-3.528;0.684] | 0.429 | -0.653 [-2.760;1.453] | 1.000 | |
ES | ∆HC-RLBP | -0.152 [-0747;0.443] | 1.000 | -0.085 [-0.680;0.510] | 1.000 | -0.036 [-0.632;0.559] | 1.000 |
∆HC-ncCLBP | -0.291 [-0.971;0.389] | 1.000 | -0.325 [-1.005;0.355] | 1.000 | -0.133 [-0.813;0.547] | 1.000 | |
∆HC-cCLBP | -0.774 [-1.425;-0.122] | 0.011* | -0.755 [-1.407;-0.103] | 0.015* | -0.366 [-1.018;0.286] | 0.796 | |
∆RLBP-ncCLBP | -0.139 [-0.809;0.530] | 1.000 | -0.240 [-0.909;0.429] | 1.000 | -0.096 [-0.766;0.573] | 1.000 | |
∆RLBP-cCLBP | -0.622 [-1.262;0.019] | 0.062 | -0.670 [-1.310;-0.030] | 0.035* | -0.330 [-0.970;0.311] | 1.000 | |
∆NcCLBP-cCLBP | -0.482 [-1.202;0.238] | 0.442 | -0.430 [-1.150;0.290] | 0.660 | -0.23 [-0.953;0.487] | 1.000 | |
MF | ∆HC-RLBP | -0.300 [-1.512;0.913] | 1.000 | -0.203 [-1.416;1.010] | 1.000 | -0.116 [-1.329;1.097] | 1.000 |
∆HC-ncCLBP | -0.615 [-2.001;0.771] | 1.000 | -0.681 [-2.067;0.705] | 1.000 | -0.198 [-1.584;1.188] | 1.000 | |
∆HC-cCLBP | -1.620 [-2.953;-0.287] | 0.009* | -1.563 [-2.896;-0.230] | 0.013* | -0.809 [2.142;0.525] | 0.629 | |
∆RLBP-ncCLBP | -0.315 [-1.675;1.045] | 1.000 | -0.478 [-1.838;0.882] | 1.000 | -0.082 [-1.442;1.278] | 1.000 | |
∆RLBP-cCLBP | -1.320 [-2.627;-0.014] | 0.046* | -1.360 [-2.666;-0.054] | 0.037* | -0.693 [-1.999;0.614] | 0.932 | |
∆NcCLBP-cCLBP | -1.005 [-2.473;0.463] | 0.406 | -0.882 [-2.350;0.586] | 0.648 | -0.611 [-2.079;0.857] | 1.000 | |