Effects of Motor Imagery on Skin Conductance and Pelvic Floor Sensorimotor Condition: A Randomised Controlled Trial

The main aim was to assess the effects of motor imagery (MI) plus pelvic floor musculature (PFM) isometric exercises (IE) on skin conductance and pelvic floor sensorimotor condition. Thirty healthy women were randomised into two groups: MI+IE (n = 15), and sham-MI+IE (CG) group (n = 15). A pre- and post-intervention evaluation was conducted. Regarding the skin conductance, significant between-group differences were found in favour of MI+IE in the imagination phase with a large effect size (mean differences (MD)=1.79 μS, p = 0.037, d = 0.82). This greater sympathetic activation in the MI+IE group was accompanied by significantly greater hypoalgesia on presumed referral area of menstrual pain compared with the CG with a moderate effect size (MD = 0.722 Kg/cm², p = 0.048, d = 0.76). Finally, regarding the PFM strength, significant between-group differences were also found in favour of MI+IE compared with the CG with a large effect size (MD = 64.9 g, p = 0.035, d = 0.81). The results showed that adding MI to an IE program resulted in statistically greater improvements in pelvic floor sensorimotor function than IE alone in a single session and this should be considered clinically. Finally, one of the neurophysiological mechanisms by which the greater hypoalgesia generated in the experimental group could be explained through the activation of the sympathetic-excitatory system.