Hamid Zamani - Rehabilitation Research Center, Department of Physiotherapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
Mahdi Dadgoo - Rehabilitation Research Center, Department of Physiotherapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
Mohammad Akbari - Rehabilitation Research Center, Department of Physiotherapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
Javad Sarrafzadeh - Rehabilitation Research Center, Department of Physiotherapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
Mohammadreza Pourahmadi - Rehabilitation Research Center, Department of Physiotherapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran

Background: Recurrent low back pain (RLBP) affects different structures in the lumbar spine. Exercise therapy is highlyrecommended as one of the first-line treatments. One crucial variable introduced to enhance RLBP is the externalfocus. The present study aimed to investigate the effects of external focus training on pain, the thickness of transverseabdominis (TrA), internal oblique (IO), external oblique (EO), and lumbar multifidus (LM) muscles, kinesiophobia, fearavoidancebeliefs, and disability of people with RLBP.Methods: This randomized-controlled trial consisted of ۳۸ RLBP patients. Patients were randomly divided into two groupsthe treatment group (n=۱۹) that received external focus training in addition to motor control training and the control group(n=۱۹) that received motor control training alone. The primary outcome was pain intensity, and secondary outcomes werethe thickness of TrA, IO, EO, LM muscles, kinesiophobia, fear-avoidance beliefs, and disability that were measured at thebaseline and after ۱۶ sessions of interventions. The interventions were performed three sessions weekly.Results: Reduction in pain intensity was more significant in the intervention group than in the control group (P<۰.۰۰۱, Cohen’sd=-۱.۴۷). The thickness of TrA muscle in the contraction condition of the intervention group was significantly more on the leftside (P<۰.۰۰۱, Cohen’s d=۱.۰۵) than on the right side (P=۰.۰۳, Cohen’s d=۰.۴۴). Other outcomes showed no significantdifferences. However, the Cohen’s d effect size for the left IO (Cohen’s d=۰.۵۷) and TKS (Cohen’s d=-۰.۵۳) were moderate.Conclusion: In RLBP patients, external focus and motor control training could effectively reduce the pain. Althoughthis intervention could increase the thickness of the TrA muscle of RLBP, it has no significant effect on the thicknessof IO, EO, and LM muscles. In addition, the obtained results indicated that this intervention has no significant effect onkinesiophobia, fear-avoidance beliefs, and disability..Level of evidence: I

abdominal muscle, Disability, Exercise therapy, lumbar region, recurrent low back pain