Influence of Pelvic Angles on Back Muscle Activity during Upper Limb Elevation

Abstract

[Purpose] This study investigated the influence of pelvic angles on back muscle activity during upper limb elevation. [Subjects] Ten healthy males participated in this study. [Methods] We measured back muscle activities at 5° anterior pelvic tilt, and 5 and 15° of posterior pelvic tilt while sitting with upper limb elevation of 90°. Surface electromyography of the activities of the right trapezius upper fibers, middle fibers, lower fibers, lumbar erector spinae and lumbar multifidus were recorded. [Results] Posterior tilt of the pelvis decreased the lumbar multifidus activity, but increased trapezius muscle activity. [Conclusion] The results suggest that exercise of the back muscles with 5° anterior pelvic while sitting would effectively activate the lumbar multifidus.