back extension

Usage notes
This term is a misnomer since if applied to the variation where the pelvis is placed above the pad of the device it is performed upon the hip is flexed and extended and the trunk is only trained isometrically so no back extension is present, whereas when the pelvis is lying on the pad the trunk will be flexed and inasmuch extended only to its upright default (or neutral) position so the back is exactly not hyperextended.