Hold a bar at hip level with a pronated (palms facing down) grip. Your shoulders should be back, your back arched, and your knees slightly bent. This will be your starting position.
Lower the bar by moving your butt back as far as you can. Keep the bar close to your body, your head looking forward, and your shoulders back. Done correctly, you should reach the maximum range of your hamstring flexibility just below the knee. Any further movement will be compensation and should be avoided for this movement.
At the bottom of your range of motion, return the starting position by driving the hips forward to stand up tall.