Effects of Motor Imagery and Action Observation on Lumbo-pelvic Motor Control, Trunk Muscles Strength and Level of Perceived Fatigue: A Randomized Controlled Trial.

Purpose: The aim of the study was to evaluate the effects of motor imagery (MI) and action observation (AO) combined with a motor control exercises program for the lumbopelvic region. Method: Forty-five asymptomatic individuals were randomized into three groups: MI (n = 15), AO (n = 15) or control group (CG) (n = 15). The outcome measures included lumbopelvic motor control measured with a stabilizer pressure biofeedback, trunk muscle strength using a dynamometer and the perceived fatigue using a visual analogue scale. Participants were assessed at pre-intervention, at first week of intervention (mid) and post-intervention. Results: Regarding lumbopelvic motor control, we observed significant within-group differences between pre- and the mid and post-intervention assessment in AO group (p < .001, d > 0.80). MI and CG groups showed significant differences between pre- and post-intervention assessment (p < .05, d > 0.80). Regarding the direct comparison in the ΔMid-Pre differences between groups, only the AO group was superior to the CG with a large effect size (d > 0.80). Regarding trunk muscle strength, significant within-group differences between pre- and post-intervention assessments were observed in AO (p < .001, d = -1.25) and MI (p < .05, d = -1.00) groups. In relation to the perceived fatigue, statistically significant within-group differences were found in all groups (p < .05, d > 0.60). Conclusion: AO training caused faster changes in lumbopelvic motor control compared with the CG group. The AO strategy could be used as a guideline for teaching lumbopelvic motor control exercises.