EMG Activity of Trunk Muscles in Patients with Chronic Low Back Pain after Fatigue

Fatigue, Abdominal muscle, EMG, co-contraction, loading Background: Low back pain (LBP) is one of the most prevalent musculoskeletal disorders. Altered movement patterns in LBP patients can reflect changes in neuromuscular control. Objective: This study aimed to assess trunk muscle electromyographic (EMG) response after trunk extensor muscle fatigue in LBP subjects. Methods: Sixteen patients with chronic non-specific LBP and twenty healthy matched subjects volunteered to participate in this interventional study. EMG activity of trunk muscles was assessed before and after lifting fatigue task in two groups. Multivariate Analysis of variance (MANOVA) was used for statistical analysis. Results: The results were significant for the main effects of fatigue (F=6.64, P <0.05) and interaction of group by fatigue (F=5.34, P <0.05) in lower erector spine muscle activity. Conclusions: Muscular fatigue is not unusual in daily activity and work place. According to the results of the current study, trunk extensor muscles fatigue altered trunk muscles activation in both healthy and CLBP but the alteration was greater in CLBP patients.