Activity of Posterior Oblique Sling Muscles during Quadruped Hip Extension with Different Shoulder Positions

Abstract

While various studies have been conducted on trunk muscle activation in the quadruped position, no research has been conducted on posterior oblique sling (POS) muscle activation in the quadruped position despite its clinical importance. It has been demonstrated that the movement of the upper extremity affects the muscle activity of the contralateral lower extremity through the POS. The purpose of this study was to compare the EMG of the POS muscles during quadruped hip extension (QHE) with different shoulder positions. The participants performed hip extension in the quadruped position without shoulder movement (quadruped hip extension; QHE), QHE with shoulder extension and internal rotation (QHE with SEI), and QHE with shoulder flexion and external rotation (QHE with SFE). EMG of the POS muscles was measured during three different positions. During the QHE with SFE position, the lower trapezius has the highest EMG among all the POS muscles. Additionally, the contralateral erector spinae, ipsilateral erector spinae, and gluteus maximus presented higher EMG activity during QHE with SFE than during QHE and QHE with SEI. Therefore, QHE with SFE position may be clinically recommended as an effective exercise to improve EMG activity of POS muscles and increase lumbopelvic stability.