“You can’t improve fitness two weeks before the marathon, but you can ruin your race by trying.”

The fall marathon season is almost upon us. Next week, the TCS Sydney Marathon makes its debut as a world major, which means thousands of runners all over the world are now “tapering.”

Tapering simply means reducing your training load or “resting” before a race to optimize performance.

A proper marathon training block, which can last anywhere from 16 weeks to six months, can be grueling and a runner’s body needs to recover fully from all the accumulated fatigue. A proper taper, on the other hand, should last at least two to three weeks.

Oddly, runners’ bodies react differently to tapering. While one would think that taper time is most awaited, some get really sick after diminishing training load. Some runners feel depressed or anxious about “losing fitness” as they have become used to high mileage.

The temptation to continue doing hard efforts til race day can be difficult to resist, especially those who are “cramming.” But resist it, you must.

One cannot really improve on fitness in those last two weeks.

According to science, physiological adaptations like mitochondrial density, capillaryization, VO2 max changes typically take 10 to 21 days to show measurable effects. Any hard training after that point just builds fatigue without performance benefit.

This doesn’t mean that one should stop running or any physical activity altogether. The key is maintaining intensity while significantly reducing volume, and avoiding workouts that are too fatiguing or risk injury.

A paper published in the International Journal of Sports Medicine reviewed more than 50 scientific studies on tapering found an improvement of about 3 percent in performance when athletes reduced their training before competition. This can spell the difference between getting one’s PR or not.

According to a Runner’s World article, tapering does not just result in proper recovery of muscles. Many of the biggest gains actually occur in the circulatory system, where total blood volume and red blood cell counts increase. Tapered athletes note increases in VO2 max and running economy, and increased ability to store more glycogen.

“Reducing training allows your body to consolidate its gains,” said Pete Pfitzinger, author of Advanced Marathoning.

“Physiologically, every athlete will benefit from a taper. If an athlete does not respond well to a taper, then either the taper was not well-designed or the athlete has it in their head that they do not need to taper.”

Admittedly, I was a bit skeptical too about the benefits of tapering years back when I was new to marathon running. But as a relatively older runner, I now find that tapering is even more important.

I may not feel the fatigue, but that doesn’t mean it doesn’t exist. Proof is that I am able to do harder efforts after periods of proper rest.

Tapering, of course, does not just entail deloading. This is when one should be even more meticulous about diet like increasing protein intake, dropping alcohol and excessive caffeine, and frontloading electrolytes.

Finally, this is also the period to really catch up on sleep. Sleep promotes muscle protein synthesis and reduces systemic inflammation.

Remember, at this point in one’s training, whatever fitness one has gained is already in the bank.

You simply withdraw from it on race day.