hey, well i do my ab days every 2 days. i always do crunches till im hot in the face, then byccile things until im red in the face, then reverse crunches. the thing is, when i do crunches for a long long time. then rest, when i start up again, it doesnt burn! i could go on forvere and not feel a thing! and its a waste of time! do i have to do a bunch of sets or jjust quit until im red in the face?
If you wake up the next morning and feel like you've been punched in the stomach you've probably done it right lol, or thats what I think anyway.
If you need more exercises try sitting on a bench, balancing yourself with the palms of your ahnds and slwoly swinging up your legs until they are parralel to the ground.
If you can hold your legs like that (straight inf ront of you) you've already got good abs, and if you can then push them straight up in the air so they are facing straight up in the sky like two arrows then you've get really good abs.
Of course, the important thing is being able to hold the position. Now THATS what abs are all about.