Simply put, between two and three weeks out from any Big Race, rookie runners and veterans alike go through a period of uncharacteristic self-doubt and speculation. We call it taper-induced endurance runner neurosis, TERNs for short. It’s a form of temporary lunacy in which the symptomatic runner begins questioning his or her training, or worse yet, changing their habits dramatically, during the final days before the Big Race.

We, as the guardians of all running truths, see a flood of runners asking about whether or not double-knotting will improve performance on race day, whether Body Glide is really that helpful (it is), how much water to drink the night before the race, whether or not a beer will ruin their taper, and myriad other strange, yet fully rational, questions.

And we’re forced to answer these questions, time and time again, in a way that helps to not only reinforce the positive (you’ve done so much work, you’ve got this thing nailed!), but also to dissuade the runner from making any radical changes to their strategy.

What’s our number one response? “If it ain’t broke, don’t fix it.” It may not be original, eloquent, or inspiring, but we’ll be damned if it’s not universally applicable. Try it.

The problem with the taper period in any training regimen is it creates a rather long sentence of pure boredom, characterized by an undeniably high energy level, and punctuated by the event itself. For most first-timers, that punctuation is a big ol’ question mark, which lends itself to a whole lot of uncertainty in the interim.

Runners often enter training campaigns with a relatively pragmatic outlook: if I do A, B, and C exactly as prescribed, I should be able to get through this thing alive. And, by and large, these runners stick to their training regimen as prescribed for the first few weeks, before life gets in the way. The dreaded Norovirus comes along on your winter vacation, wreaks unholy terror on your GI, and wipes out your 16-mile long run. A late March snowstorm makes the 21-miler take a full hour longer than expected.

But for the most part the training takes care of itself, and runners find themselves at the peak of their fitness curve just before the taper. The temptation to scrap the taper runs as prescribed and go for a run twice as long is unbearable. The temptation to scrap the race entirely and just eat ice cream can be equally compelling. Hell, you’re in great shape; you earned a good weekend of JP Licks.

But one must not give into such temptation!

The taper is as much about willpower and resisting the urge to go off the rails as it is about rest and relaxation. As counterintuitive as it may feel to sit on your butt and waste all that precious fitness acquired in the preceding weeks, the taper is all about replenishing the body’s energy stores, restoring hormonal and nutritional balance, and repairing damaged muscles. This simply cannot be achieved through casual neglect of the taper as written.

The workout structure of the taper is centered upon exercise volume and intensity that will neither build additional fitness (hard to do in such a short period) nor further tax the body’s systems.

The taper is not a time in which to, for example, try a brand new model of shoe that just landed on the market. It is not a time to try to acclimate to a different energy gel, nutritional or dietary supplement, nor to test the limits of hydration. And it is unquestionably not a time to “wing it” with your training.

The final weeks before the Big Race are an opportunity to fine tune the machine built in the first three-quarters of the training period. Make the mileage count, stretch, rest, relax, and don’t change anything.

If you need new shoes, buy the same model you’ve been training with unless you have compelling evidence to suggest you need something different (i.e. injury; new, additional toes; etc.). And if you’re not planning on breaking the sound barrier, don’t switch from trainers to racing flats for your first marathon.

The same rules apply to socks. If you’ve managed to run throughout your entire training period in knee high cotton bumblebee-striped toe socks, by all means continue to do so.

If you want to double-knot your shoelaces, you absolutely may. It will have no impact whatsoever on your time (unless, of course, you would otherwise have endured a total blowout on the course with single-knotted laces).

If you’re thirsty, drink water. In reasonable amounts. If you’re able to read this article, we trust your ability to reason AND to estimate your water needs.

If you want a beer, have a beer, especially if it’s been part of your routine for the past several weeks. Just don’t have 20 beers. Unless that, too, has been part of your routine (in which case we suggest changing your habits promptly after the Big Race).

And lastly, for your own sake and for the sake of those around you: don’t skimp on the Body Glide. Trust me.