I've realized that my physical ability to continue training on a given day is directly linked to my spirit. For instance, here in Baltimore it gets awful-heinous hot and humid in the summer. It kills me, and after an hour of training I feel like keeling over. I have nothing left to do the second hour with, except spirit. I find some of the most profound revelations about the nature of what I'm trying to learn occur in this state. I think that experiencing this, and noticing it has caused me to grow in ways I hadn't considered possible.
Not sure if this is what you mean, but that's all I've got!