Sit on the ground with a bench behind you, bending your knees so your feet are planted on the ground and holding a barbell resting below your hips. Lean back so your shoulders are on the bench and position the bar above your hips. Drive your hips up lifting the bar. In the top position your knees should be bent at 90° and your shoulders should be near the top of the bench, with your body forming a straight line between them. Pause at the top of the lift and squeeze your glutes, then lower your hips slowly.