Calculus final coming up tomorrow?

No problem. Brew a pot of coffee and cram, right?

Presentation for the corporate bigwigs in a week?

You can't practice enough.

Marathon two weeks away?

Sit. Take a load off. Fix yourself an iced tea. Catch up on your "Grey's Anatomy."

As counterintuitive as it may feel to distance runners who have spent the better part of the summer and fall training their bodies to run 26.2 miles, the weeks just before the marathon are a time for reigning in the mileage and tempering the compulsion to run long and hard.

"We tell our runners that there's nothing they can do at this point," says Norman Uyeda, a volunteer coach at the Honolulu Marathon Clinic. "If you didn't train consistently before, there's nothing you can do at this point. The only thing you can do (by training hard) now is injure yourself."

Regardless of a runner's level of ability and experience, a successful marathon training program will always conclude with at least a couple of weeks of tapering — an incremental decrease in mileage and exertion that allows for recovery from fatigue and minor injury and a gathering of physical and psychological resources.

Veteran runner and coach Brian Clarke has safely guided hundreds of beginning marathoners to successful — and enjoyable — marathon finishes, in part because of his emphasis on effective tapering.

"We expect our runners to really hold themselves back during the last two weeks," Clarke says. "A lot of times, runners will forget themselves on a training run and really rip it. That's a mistake because they won't be that energetic for the marathon. This is a completely different period in their training."

Many inexperienced distance runners struggle with the idea that not training can be beneficial.

"Some feel that if they don't train, they're de-training," Clarke said. "You don't de-train in two weeks. Some have to take it on faith that if you hold back, you'll have tremendous energy for the race."

After logging 20, 30 or 40 miles a week for several months, many runners are brimming with newfound confidence and, perhaps, a deceptive feeling of good health. In fact, even with appropriate rest days scheduled into their weekly regimens, many would-be marathoners experience some level of fatigue or chronic dehydration by the time the marathon approaches. Many also suffer from nagging injuries — from sore muscles to tendinitis — that they've trained themselves to ignore.

"Training is a process of breaking down and recovering," Clarke says. "Tapering is a process of building up."

The tapering period does not allow runners to recover from their rigorous training, but allows them to rehydrate, refuel, and most importantly, put themselves in the best position to enjoy bountiful energy during the race.

Reactions to the new regimen of shorter distances and lower exertion can be mixed. While some find themselves chomping at the bit, others may feel more fatigued than usual.

"Runners have to realize that the mind is withholding psychic energy during the week before the marathon," Clarke says. "The activity of tapering is meant to compensate for this withholding."

As Clarke explains, the mind's unconscious reaction to the knowledge of impending major exertion is to control the hormonal process that governs the bodies preparedness for a long run. As it does this, the runner's capacity to run hard is diminished. However, once the race starts, the floodgates open and — as long as the runner has trained consistently and tapered intelligently — he or she will have the energy for optimal performance.

"I've been exhausted before during the week before a race, even when I was running shorter and slower," Clarke says. "But once the race begins, I had tremendous energy and good ability."

Reach Michael Tsai at mtsai@honoluluadvertiser.com.