Sit on the floor, knees bent, lean back slightly, and twist your torso side to side while holding a weight or medicine ball. This engages the obliques.
Get into a side plank position, then slowly lower your hips towards the floor and lift back up, engaging your obliques and core muscles.
Lie on your back, hands behind your head, and bring your knees up. Alternately bring opposite elbow to knee in a cycling motion, engaging both the upper and lower abs.
Use a resistance band or a cable machine, starting with arms high and pulling down diagonally across your body to engage obliques and core.
Stand with feet shoulder-width apart, raise one arm and lift the same side knee towards it, crunching sideways. Alternate sides.
Lie on your side, legs extended, and lift both legs and upper body towards each other, engaging the side abdominal muscles.
Stand tall, hold a dumbbell or a kettlebell in one hand, and bend sideways, engaging the obliques. Alternate sides.
Get into a plank position and alternate bringing your knees towards your chest quickly, engaging both core and obliques.