AzT, it's interesting you mentioned "shallow pain-cave". I had exactly that thought today when I was preriding the road I want to use for the next FTP test. Barb was riding me off her wheel, again, and I was wondering what I had to do to either catch her, or stay with her. I was in the pain-cave, but not terribly deep, but still, I hurt like hell. When we stopped for a little break I thought about that, and I felt that I could go deeper, but I also realized that I didn't really know how. The pain-cave can be scary, but what's interesting to me about it is that the few times I have REALLY dug deep into it (in races), I always come out the other side none the worse for wear. Even knowing that, I am more often than not reluctant to push over that edge.