Thursday, September 21, 2017

The Taper: Staring Into The Abyss (Part I)

Heather Cote prepares for
her "Apex" run in the
Pemi Wilderness
Photo: Heather Cote
"Although our intellect always longs for clarity and certainty, our nature often finds uncertainty fascinating." -Carl von Clausewitz

If there's one thing that terrifies an endurance athlete more than anything else it's the dreaded taper.  In endurance sports of marathon distance or greater, tapering is the practice of reducing training volume in the weeks leading up to an event in an effort to optimize performance on race day.  And while endurance athletes intuitively understand the importance of it, that does not preclude them from fearing it.  In Part I of this review on tapering let's look at the purpose, the particulars, and the potential reason's why it's so difficult.  

The Purpose
In my previous entry, "Keep Easy Days Easy", the concept of form was introduced.  By way of review, today's form is the difference between yesterday's fitness and yesterday's fatigue.  Remember that both fitness and fatigue are cumulative.  The purpose of tapering is to reduce accumulated fatigue while maintaining fitness in an effort to bring form close to zero.  The exact ratio of fitness and carried fatigued is athlete-specific with some measure of trial and error done during early season "B" events.

The Particulars
There are a number of important specifics of the taper including the length, the volume, and the specific workouts.  Let's look at each individually.

The Length
The length of a taper is based on the duration (or length) of the event.  My general rule is four (4) weeks for events of marathon distance or greater.  That is to say, the training volume is gradually reduced for four weeks following the apex training unit.  The apex training unit is the last long event-specific training unit of the specific-preparation block.  For instance, in marathon training this would mean the last long run of the training cycle (ie. 20-22 miles).  

The Volume
With a taper of up to 27 days it's critical that the volume is reduced gradually.  Remember, the purpose is to shred the fatigue accumulated over the previous two weeks of training while maintaining the fitness gained in the previous three months.  A reduction of weekly training volume of 15-20% works for most athletes.  However, it's important to keep a daily eye on both form and subjective "post-activity" comments from the athlete to assure that fatigue is being adequately reduced.

The Specific Workouts
While reducing fatigue is priority #1, the maintenance of sport-specific fitness is a close #2.  My typical marathon or ultramarathon training plan has two "workouts" a week.  These generally include an up tempo training unit and a long run.  During the taper both of these training units remain on the schedule but their volume is systematically reduced.  The most effective way to reduce fatigue and maintain fitness during a taper is to reduce training unit duration while maintaining training unit intensity.  An example would be the following;

Apex Week
Tuesday Tempo: 30 minutes @ 1/2 marathon pace

Taper (1)
Tuesday Tempo: 20 minutes @ 1/2 marathon pace

This also holds true for the long run.  The total distance is reduced but the athlete is still expected to run a prescribed number of miles during that training unit at marathon goal pace.  

Then why is it so difficult?
While the reduced training volume during a taper is physically easier on the athlete, many report it being psychologically more difficult.  And the reason may surprise you.  

The effects of moderate aerobic exercise on improving mood state, sleep quality, and sense of well-being are well established in the scientific literature.  Yet the underlying causation of these effects has been open for debate.  The "runners high" is the rainbow-colored unicorn of the running world.  In other words, it's the most desirable outcome of running that few experience and none can consciously elicit.  But scientists are getting closer to understanding why the phenomena occurs and one theory suggests it's related to cannabinoids.

Yes indeed these are the same chemical constituent components found in marijuana but these cannabinoids are endogenous meaning that we produce them in the brain.  These endocannabinoids are produced as a result of moderate-high intensity physical activity (like running) and bind to opioid receptors in the brain.  When these opioid receptors are activated they cause two important effects; they blunt pain and act in the "reward" centers of the brain making running feel more "pleasurable".  
It's entirely plausible then that following months of training a runner might adapt to a certain level of circulating endocannabinoids and the resulting stimulation of the reward centers of the brain.  During a taper when training volume is drastically reduced (by either duration or more importantly intensity) a withdrawal may occur and result in the subjective feelings of restlessness, altered mood state, and disordered sleep patterns.  

One way to potentially mitigate these subjective feelings is to slowly reduce circulating levels of endocannabinoids by gradually reducing overall training volume but maintaining training intensity (ie. as in the Tuesday Tempo example above).  

A well designed taper will reduce fatigue, while maintaining fitness, and mitigate the psychological effects of the reduced training load.  

In Part II we will discuss the nutritional and mental priorities and practices during a taper.

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