The most important element to a successful marathon is flexibility in your training. And I'm not talking about the ability to bend it like Beckham, or like the contortionist below.
No, I'm talking about the ability to have some 'give' in your training plan. Sure, when some people get their nice and new training plan, all shiny and full of perfect expectations, we promise we will be so utterly devoted to it that it would make a high school girl think we were being a little clingy. We stay up late thinking of ways we will please our new little training plans and how this time things are going to be different.
But, honestly, things won't be different. You are the same lazy slob as last time and if your old training plan ever gets your new training plan's phone number she'd set her straight. Wait...that isn't quite what I wanted to talk about.
Back to training. So, you might wake up on a Tuesday morning and grab all of your workout stuff and plan on doing your track workout later that evening when you car hits black ice and spins on the highway. Then maybe your car decides to hit a wall of concrete and is completely destroyed. Given the propensity of SUV's to do cartwheels, I was glad all that happened was my vehicle smashing into the highway barrier. But, Tuesday's track workout was off the books.
Alas, I was--amazingly--uninjured. And I just pushed that silly little track workout to Wednesday. Yeah, that made my pace workout on Thursday night extremely difficult, and I bailed on the last two miles of it. But I was flexible about it.
If you can't allow for a little flexibility in your training schedule, you are sunk. Training for Grand Rapids I rolled an ankle and had to eat a long run. But the ability to make some adjustment and to trust in both your prior training, and your remaining training, is unquestionably the most important trait necessary to survive the difficulty of training over the course of four months.
So stay bendy my friends.