Lie supine on mat or bench. Bend knees and hips and place feet on floor. Extend arms down to sides.
Flex waist to raise upper torso from mat or bench. Keep low back on floor or mat and raise torso up as high as possible. Extend hands toward sides of heels. Return until back of shoulders contact mat or bench. Repeat.
Certain individuals may need to keep their neck in neutral position with space between their chin and sternum, particularly if hands are placed behind head. See Spot Reduction Myth. Also see Curl-up / Half Sit-up Test.
Deconditioned individuals can start on slightly declined board.
Exercise can be made more challenging by placing hands further up toward head. See Arm Position During Waist Exercises. Exercise can also be performed on incline board or with additional weight.