Hanging oblique knee raise

Hang from a pull-up bar with your arms fully extended and your palms facing away from you. Engage your core and lift your knees towards your chest, twisting your torso to the side as you do so. Pause for a moment at the top, then slowly lower your legs back down to the starting position. Repeat on the other side, twisting your torso in the opposite direction. Continue alternating sides for the desired number of repetitions.