The results of the two-way ANOVA showed a significant main effect of position (F ¼ 72.118, p < 0.001).
There were no significant differences between groups for any position and no significant interaction between position and group.
There were no significant differences between right and left CSA for LM when normalised to the resting position (Table 2).
There was a highly significant difference between normalised positions such that CSA area was
significantly greater for SB than SS (t¼6.167, df ¼ 39, p < 0.0001).
In other words LM CSA increased as the lability of the surface increased for both groups, demonstrating that SB is more effective at stimulating LM activity (Fig. 3). Lastly, there were no differences in LM CSA at rest between participants with CLBP and HCs.