Effect of functional leg length inequality on the quadratus lumborum muscle by using EMG signal on asymptomatic population

Abstract

Objectives: The objective of the study was to analyze the electromyography signals of quadratus lumborum muscle activity on pelvic asymmetry and leg length inequality as this might cause serious injuries in lumbar spine and lower extremity. Subjects and Methods: This was a randomized control trial with a total of 60 participants that were all are right handed and that were assessed manually and by tape measurement for leg length inequality then by electromyography (EMG) in two positions to determine the activity of quadratus lumborum muscle. Results: In the resting position, the power spectral density to analyze the EMG signals results showed that the right side upper pelvis crista iliac position EMG signals were higher in the right than the left side of the quadratus lumborum muscle. The left side upper pelvis crista iliac position had higher EMG signals on the left side than on the right side of the quadratus lumborum muscle activity. Moreover 98% of participants who have up right iliac crista also had short LLI. Additionally, 96% of participants who had up left iliac crista also had short LLI. Conclusions: In conclusion the present study shows that asymmetry in pelvis or QL activity can be caused by LLI which might cause serious injuries in the lower extremities or lumbar spine.