The most common mistake people make is not to consciously contract ther abs. I could tell you to do planks, but you know what? I have a surface e m g unit that measures muscle activity. Do a plank have zero ab activation? What? None? Where? Where is their activation? Loback, lowback. K, high plank position. Is it better to be on your hands? I usually do a on my forearms, on my elbowsi i definitely don't want to say there's a better and worse. But what it is is the starting with scoop. You need to actually press your shoulder blades around your ribs, towards your nipples. They have to move around