This movement must occur from your hip joint, not your back, so you should experience the muscles of your respective buttocks working, these are your gluteal muscles. The hip joint is the biggest and strongest joint in Your system that bears bodyweight. It’s inside the ball and socket joint composition https://www.theorthopaedicandpainpractice.com/what-is-avascular-necrosis-of-the-hip/?_gl=1*xbbxlb*_up*MQ..&gclid=Cj0KCQjwkt6aBhDKARIsAAyeLJ2krYJSOuy5mZksrNqH-VDjQwW1ScD49yD8BUWysDG6u6bJPCSbXVUaAuCPEALw_wcB