This exercise works the abs muscles and deep back muscles.
Stand up straight with your feet shoulder width apart.
Place a bar on your shoulders.
As you inhale, bend to the side slowly.
As you exhale return to the starting position.
Now repeat the movement bending to the other side.
Do the exercise slowly, otherwise you can injure your back!
This exercise impacts the lower back. If you feel discomfort while performing this exercise, it is better to avoid it.