The effects of pelvic diagonal movements and resistance on the lumbar multifidus.

[Purpose] The purpose of this study was to compare the effects of pelvic diagonal movements, made with and without resistance, on the thickness of lumbar multifidus muscles. [Subjects and Methods] Participants in this study were healthy subjects who had no musculoskeletal disorders or lumbar-related pain. Participants were positioned on their side and instructed to lie with their hip flexor at 40 degrees. Ultrasonography was used for measurement, and the values of two calculations were averaged. [Results] The thickness of ipsilateral lumbar multifidus muscles showed a significant difference following the exercise of pelvic diagonal movements. The results of anterior elevation movements and posterior depression movements also demonstrated significant difference. There was no significant difference in lumbar multifidus muscles thickness between movements made with and without resistance. [Conclusion] These findings suggest that pelvic diagonal movements can be an effective method to promote muscular activation of the ipsilateral multifidus. Furthermore, researchers have concluded that resistance is not required during pelvic diagonal movements to selectively activate the core muscles.