1) your doing them wrong if you go all the way up, when you go all the way up thats a normal situp and doesnt do much crunches are only where you go up until your stomach is tensed from going up (only a few centimetres or couple or even 1 inch off the ground) feel with your hand... then go back down if your doing it right youll feel it after about 20 of them
2) with the pullups try to do as many as you can
My back is very flexible, so i curl up when I go up doing my crunches. (My trunk lifts go up to 19+ inches above the floor)
My stomach area (abdominals) are very solid since the last 3 years when I had to burn the fat. Just do it to keep the same everyday. My crunches go like this:
Go up, go up while facing left, go up while facing right and that becomes 1 x 400 of these. Then the next do I do it with my legs in the air (these are the crunches that makes your chest not go very high) and do same as before; then do it on the sides (left or right, alternate after done with one side at 150).