Background The high prevalence of non-specific low back pain and its correlation with the findings in the lumbar multifidus muscles (electromyography activity, morphology and thickness) and good results in motor control exercises programs to reduce pain and disability justifies the use of tools to facilitate the integration of the muscle contraction.

Methods Experimental study, randomised controlled trial single-blinded formed by 3 parallel groups: verbal order (n=5), visual feedback (n=6) and visual feedback with transcutaneous electrical stimulation (n=6). Descriptive data (age, gender, height and weight) and thickness of multifidus by ultrasound imaging data (2 pre-intervention and 2 post-intervention) were collected.

Results Statistically significant differences were found in lumbar multifidus thickness after interventions between groups (p<0.001). Thickness differences were greater in visual feedback group (0.64 cm) and visual feedback with transcutaneous electrical stimulation (0.56 cm) than verbal order group (0.29 cm). Pre-intervention measurements error were less than 0.05 cm.

Conclusions The results of this study suggest that the use of visual feedback by ultrasound imaging with or without transcutaneous electrical stimulation improve the lumbar multifidus contraction capacity in asymptomatic subjects.