Lie supine on floor or bench with knees and hips bent. Hold plate behind neck or on chest with both hands.
Flex and twist waist to raise upper torso off surface to one side. Return until back of shoulders return to surface. Repeat to opposite side alternating twists.
If weight is held behind head, position head hanging off bench. See Spot Reduction Myth. Certain individuals may need to keep their neck in neutral position with space between their chin and sternum. See Arm Position During Waist Exercises.