However, Physical Therapist and Strength Coach, Jeff Cavaliere, says it doesn’t need to be. Bringing your feet towards your head works the lower abs, while the incorporated twist works the obliques. Bringing your feet towards your head works the lower abs, while the incorporated twist works the obliques. This works the obliques, while moving your head towards your lower torso will work your upper abs. And there you have it, two ab exercises that target your upper and lower abdominals, as well as your obliques.