It doesn't matter if you can do 1,000 classic situps in one go if you're not doing them correctly. Additionally, if you're trying to lose weight or firm up there are ab workouts significantly more effective than sit ups for toning your abs. Doing just a few of these ab exercises gives you the results equivalent of lots of sit ups.
One of these special ab moves is this side twist holding a weight. It combines a sit up with an oblique twist, all while you're holding a weight in one hand. Do this exercise now and get flat abs fast.