nothing. i dont believe in giving them direct work. i want to keep a small waist line with an exaggerated v-taper.
i think u get enuf oblique work from core exercises. i never do ab work while on heavy cycle. i like the size and shape of my abs. they are muscles just like biceps. if u work biceps hard and eat right they will grow. if u work abs hard what is to prevent them from getting too big??? so i just skip them
i always have felt that u get enough oblique work from core exercises such as deads, squats, standing presses, etc.