Kneel on floor with forefeet on gliding discs. Place hands shoulder width apart on floor. With arms vertical and straight, support body off of floor while sliding gliding discs back until body is straight.
From plank position, raise rear end up as high as possible by bending hips. Pull gliding discs toward hands while keeping knees straight. Return by extending hips to original position. Repeat.
Keep arms straight with shoulders positioned above hands. Rectus Abdominis and Obliques only contract dynamically if actual waist flexion occurs. With no waist flexion, Rectus Abdominis and External Oblique act only to stabilize pelvis and waist during hip flexion. If waist flexion were to occur after complete hip flexion, resistive forces are no longer working against abdominal muscles in this final position when knees and hips are flexed. However, abdominal muscles are activated isometrically to keep spine straight when knees are not under body. Also see Spot Reduction Myth and Lower Ab Myth.
Allow knees to bend in a jack-knife movement to decrease intensity.
For greater intensity try performing on slightly inclined slope.