Dumbbell side bend

Stand up straight with your feet shoulder-width apart and hold a dumbbell in one hand, letting it hang down by your side. Keeping your back straight and your core engaged, slowly bend sideways at the waist towards the opposite side of the dumbbell, lowering the weight as far as you comfortably can. Pause for a moment, then slowly return to the starting position. Repeat for the desired number of repetitions, then switch sides and repeat.