So my trainer did this one exercise for the belly. You lay on your back and someone stands over you by your shoulders, and you hold on to their ankles. You bring up both your legs together and whom ever is standing over you. They push your legs down quickly and you bring legs back up and they push them back down again. You want to do this quickly. And to work on your side the person pushes your legs to the side. And when you so this you don’t want your legs touching the floor.