Affiliations: [a] Faculty of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran | [b] Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran | [c] Information and Industrial Engineering, Hanyang University, Seoul, Korea
Correspondence:
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Corresponding author: Nader Maroufi, Faculty of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran. P.O Box: 15875-4391. Tel.: +98 21 2222 7159; Fax: +98 21 2222 0946; E-mail: n-maroufi@tums.ac.ir
Abstract: Objectives:Previous research has shown inconsistent findings regarding muscle endurance in chronic low back pain (CLBP). Questions also remain about muscle endurance in patients with clinical instability. The aim of this study was to investigate trunk muscles strength and endurance in CLBP patients with and without clinical instability. Methods:32 CLBP patients (15 with and 17 without clinical instability) and 39 matched healthy subjects participated in this study. The standing extension test was performed to assess the strength and endurance of the lumbar extensors while recording their electromyographic activity. The patients’ disability was evaluated using the Oswestry and Roland-Morris Disability Questionnaires. Results:Patients with clinical instability showed lower maximal voluntary exertion (MVE) and higher time to fatigue (TTF) compared to healthy subjects (P=0.000 and P=0.008, respectively) and patients without instability (P=0.002 and P=0.02, respectively). There was no difference in these variables between patients without instability and healthy controls. A negative relationship between MVE and TTF and a positive correlation between disability and pain intensity were seen. Conclusion:Strength training of trunk extensor muscles can be considered as part of the treatment protocol for CLBP patients with clinical instability. Although patients without instability suffered from pain or disability, they showed more similarity to healthy subjects in terms of trunk muscles strength and endurance.
Keywords: Instability, low back pain, muscle strength, endurance
