What's past is prologue.
It's one of Shakespeare's most famous lines (The Tempest), though it's not always - or even often - attributed to him. It's crossed over into existing as a sort of pop culture truism instead, and in so doing, having lost its original context, has lost a great deal of intent.
Typically, it's invoked as a kind of motivational quip. What's past is past. Our future lies ahead, and we can make of it what we will.
The original context is a touch more bleak. The conversants are about to commit murder, and rationalize it as merely another domino pushed over. That is, past is prologue, inasmuch as it sets in motion the acts to come. Our past is not merely what comes before our present - it largely creates it.
We're not choosing to murder. I mean, circumstances have conspired such that we can't not murder. Right? Right. Totally.
Anyway, the latter option is basically how I feel about racing. There's a lot of anxiety at the start line, but really, the matter is largely decided. Sure, fueling and pacing matters (keeping your ass on course doesn't hurt either); but for the most part, you're going to run a time that represents your fitness. (In fact, accepting that fact can go a long way towards running a smarter pace. You can't outrun your fitness; and if you try, shit goes downhill quickly.)
I like this notion.
It robs race day of some measure of crippling fear, granting it instead a sense of discovery. How good is my fitness? Lets roll it out and see.
Moreover, it assigns real significance to daily training, which could otherwise seem something of a mundane grind. You're not just doing it because you're a crippled addict - though you are, and I am, and that's ok - but to achieve an end. You're writing the prologue for your next great act. (This is also true if you don't indulge in the everyday. Tragedy is a classic form, remember.)
But, I don't know.
Some of this - all of it? - is just my rationalizing my inability to take a single solitary day off. Half marathon a week before my target full marathon. Race like hell. Run the next day. And the next. Hills Tuesday. Trail Wednesday. Tempo Thursday, then right to a concert. Wake up twice last night to calf seizures.
Enough, maybe, to make you think about the story you're writing.
Maybe. But then again, maybe not.
Maybe the sheer force of forward momentum perpetuates forward motion, maybe you go because you go, do because you do, past is prologue, the next step could only be what it is because what has come before is what it is.
Maybe. Maybe not. I don't know but it's all good because the calf feels good, and so does everything else.