How do you Develop Toughness?

At 6 AM this morning I saw a high school cross country team out running on the coldest morning of the last four months. I've learned enough to know over the years morning runs (in addition to afternoon runs) are probably only beneficial for 10% of high school students physiologically. The reason they don't get much benefit is they don't run enough in the afternoon to start. However, there is a very real benefit mentally from waking up at 5 AM or 5:30 AM and going for a run before the rest of the world has gotten up. At least there is a benefit for a high school student, the benefit seems to fade once you get out of college.

I don't have the answer to this question. I think much of toughness is internal, that is to say it is very difficult to teach another person. This is just a thought to ponder, I may follow this up with more thoughts, but no guarantee.

Trail Running Make-Up from Last Night at the Mines of Spain