Sit on incline board. Place weight between feet or use no weight. Lie supine on incline board with torso elevated. Grasp feet hooks or sides of board for support.
Raise legs by flexing hips and knees until hips are completely flexed. Return until hips and knees are extended. Repeat.
Rectus Abdominis and Obliques only contract dynamically if actual waist flexion occurs. With no waist flexion, Rectus Abdominis and External Oblique will only act to stabilize pelvis and waist during hip flexion. It may be necessary to completely flex hips before waist flexion is possible; see Weighted Incline Leg-Hip Raise. Exercise can be performed without added weight until more resistance is needed. Elevate incline to increase resistance. Knees may be kept extended throughout leg raise to increase intensity; see Weighted Incline Straight Leg Raise. Also see Spot Reduction Myth and Lower Ab Myth.