This exercise works the abs muscles and deep back muscles.
Stand up straight with your feet shoulder width apart.
Hold a dumbbell in one hand with your other hand behind your head.
As you inhale, slowly bend your body in the opposite direction from the dumbbell.
Exhale and return to the starting position.
Do the exercise slowly and don't try to jerk the dumbbell up with your body.
This exercise involves the back muscles actively that can result in waist expanding.
It impacts the lower back and can cause pain for people with back problems.
If you feel discomfort while performing this exercise, it's better to avoid it.