Running 100 miles is hard. Or is it? To be honest, very few people, even elite ultra-marathoners actually run anywhere near that distance, even when they win a race of the same length. But it feels a lot more empowering to use the word run rather than walk, jog, shuffle, limp, hobble...you get the idea. The point is that for many who might otherwise aspire to participate in events of marathon length or longer (aka 'ultra-marathons), it's hard to get past the (rather normal) notion that they are incapable of doing so. But that's ok, because as I've mentioned, it's not really about the running.
I've completed 'running' events up to 62 miles on very limited training. I've even found myself on the podium in some of the regional races at this distance**, and I certainly didn't 'run' all the way. The point is that ultra-running is really about relentless forward progress. The biggest challenges lie in the mind, not the body. That isn't to say that it doesn't help to have a fit body--but it means that elite level fitness isn't required. With enough mental tenacity, being 'fit enough' is, at least in my experience, 'good enough' for just about anything I want to do.
The idea with this training program is thus to simply get you 'fit enough' to tackle these so called 'runs' of any length, assuming you've got a bit of that mental tenacity we talked about. And as with all things, when you've got less time (ONE HOUR!) to do something in, how you're using that time becomes more important. In this case, that means focusing on increasing speed over volume and utilizing the fact that getting faster has the a very convenient collateral effect of improving endurance at slower paces, like hobbles, shuffles, limps and jogs. Sweet!