And when you do both hands and both feet it's called the superman stretch. I agree that this one is hard - I don't think I can raise my shoulders more than an inch when I do both together. And it is very hard for me not to hold my breath during these.
These are the last exercises in the infamous Core DVD where you finish by flutter kicking your arms and legs. I can hear the voice saying "and swimming and swimming for 5, 4, 3, 2, 1" as I gratefully collapse down to end the workout.
Brutal. You guys are animals.