Affiliations: [a] Physical Therapy Department of Tarbiat Modares University, Neuromuscular Rehabilitation Research Center, Semnan University of Medical Science, Semnan, Iran | [b] Physical Therapy Department, Tarbiat Modares University, Tehran, Iran | [c] Sharif University of Technology, Formation and Industrial Engineering of Hanyang University, Hanyang, Korea | [d] School of Electrical and Computer Engineer, Tehran University, Tehran, Iran | [e] Biostatistics Department, Tarbiat Modares University, Tehran, Iran | [f] Orthopedics Department, Tehran University, Tehran, Iran
Correspondence:
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Corresponding author: Dr. Sedighe Kahrizi, Physical Therapy Department of Tarbiat Modares University, Jalale Ale Ahmad High Way, Gisha, Tehran, Iran. Tel.: +98 2182884511; Fax: +98 2188006544; E-mail: [email protected]
Abstract: Background and Objectives:Intrinsic variability is present in all actions, including repetitive tasks. The aim of this study was to evaluate the variability of anticipatory postural adjustments (APAs) of trunk muscles in participants with low back pain (LBP). Material and Method:The study included 21 participants with recurrent non-specific LBP (15 men, 6 women) and 21 healthy volunteers. Standard deviation of electromyographic activity of the external oblique (EO), transverse abdominis/internal oblique (TrA/IO), and erector spinae (ES) muscles onset relative to deltoid muscle onset was recorded in 75 rapid arm flexions, and the correlation with the participants’ avoidance belief (the FABQ score) and disability (the Roland-Morris Questionnaire score) was statistically analyzed. Results:participants with LBP exhibited less variability in timing of APAs of the TrA/IO muscle compared with the control group (P=0.047). The timing of APAs of the TrA/IO muscle was significantly correlated with the FABQ score (P=0.006). There was no significant correlation between this variable and disability (P=0.09). Decrease in variability of the timing of APA of the EO (P=0.45) and ES (P=0.6) muscles was not significant. Conclusion:The variability of the postural responses of participants with LBP decreased. Restoring variability in postural control responses might be a goal in rehabilitating these patients.
Keywords: Variability, posture, fear-avoidance belief, disability, low back pain
