Sit on exercise ball. Walk forward on ball and lie back on ball with shoulders and head hanging off and knees and hips bent. Gently hyperextend back to contour of ball. Hold plate behind neck or on chest with both hands or use no weight.
Flex waist to raise upper torso. Return to original position. Repeat.
Certain individuals may need to keep their neck in neutral position with space between their chin and sternum. Exercise can be performed without added weight until more resistance is needed. Movement can be made easier by positioning hips low on ball. In contrast, exercise can be made more challenging by using positioning ball lower on back and hips higher. Some individuals may experience low back discomfort if hips are not bent so they must use smaller ball size or lower their hip position on ball. See Arm Position During Waist Exercises and Spot Reduction Myth.