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C is for Critical Volume

Several weeks ago, my husband ran the Harrisburg Marathon.  It was his eleventh 26.2er and so, while I wouldn't say he is a VERY experienced marathoner, he has been around the block a time or two.  His PR is 2:59:12, which he set at this year's Boston Marathon.  

Going into Harrisburg, my husband aimed to run under 2:55.  But he also took on some new responsibilities (namely, coaching a high school cross country team) that limited the amount of time he could train.  Instead of the 60 mile per week that he put in for Boston, he averaged in the 40 mile per week range.  He made sure to get a good long run in each weekend, but slacked (his own words) on his weekday running, usually never getting above 5 or 6 miles on a given day.  As the fall progressed, he was starting to question the idea of a 2:55 and wondered if perhaps he should pursue a less aggressive goal.  But then a funny thing happened.  He ran two lead-up races, one 10K and one 5K, and he ran them both superbly.  In the 10K, he ran very close to what he thought was an untouchable PR and in the 5K he DID PR, by almost 15 seconds.  Perhaps he was in better shape than he thought!  Perhaps 2:55 WAS an appropriate goal.  2:55 or bust!

On race day, he went out at 2:55 pace.  And he held that until about mile 23.  When I saw him at mile 25, he was not a happy camper.  He struggled mightily those last few miles, but still finished in a respectable 3:04.  When I asked him afterwards what happened he said "the conditions were perfect, my nutrition was spot on, I felt great, but then at mile 23 my legs just stopped working."  And then he finished with the most telling of all, "I guess there aren't any shortcuts in the marathon, like I had hoped."  Yep, those 20 miles/week that was missing from his training all fall came back to bite.

This story is a (rather long) way of illustrating critical volume.  Critical volume, as it relates to endurance sports, is a concept that QT2 founder Jesse Kropelnicki coined, that defines the training volume thresholds that must be met in order to achieve one's speed potential.  Wait, what?!

Let's start with "speed potential".  Have you ever used a running calculator (like the ones found here, here and here) before?  These calculators will predict a race finishing time for you, based on a time you input from a race of a different distance.  For example, you might type in your 5K PR and the running calculator will spit out a time that you should be able to run a marathon in, as based on a curve that defines how your pace changes relative to race distance.  The only problem with these calculators is, they assume you've done the volume of training needed to maintain your place on the speed potential curve.  If my 5K PR is 16:30, for example, but I only run 25 miles per week and my long run is 8 miles, that is a very bad assumption to make.  This is precisely why the running calculator on Your 26.2, also requires you to input training volume and years of experience (another measure of durability).

Nevertheless, THAT volume, the volume needed to maintain your place on the speed potential curve, THAT is the definition of critical volume.  

So what does critical volume look like for various distances?  According to Kropelnicki, it's 7/3 of the event distance, per week.  These volumes should be met for at least 5 weeks during the previous 10 prior to the taper (not necessarily 5 weeks in a row), for single sports like running.  For the marathon, this would be about 60 miles per week.  The story of my husband's marathon in Harrisburg is now starting to make sense.  He had put in the training for a good 5K and 10K (speed potential) but not the volume needed to maintain that same spot on his speed potential curve, for a full marathon.  Hence those painfully slow last several miles.  

You might be reading this and think, 60 MILES PER WEEK?  Impossible!  To which I respond, yes, that might very well be!  Running that kind of volume is certainly not for new runners, may not be for those that are often injuried, and is definitely something that should be gradually built towards.  I'd like to make it clear that I'm definitely NOT suggesting that you MUST consistently run 60 miles per week before even considering a marathon.  There are many people who successfully complete marathons and other distances without reaching critical volume.  However, it is important to note that without reaching critical volume, that speed potential curve will likely not hold true to form.  Therefore, expectations and MOST importantly, race pacing should be adjusted accordingly.  At Your 26.2, these are the types of factors that help direct our training plans and race pacing plans.  

Read more about critical volume in Kropelnicki's own words here.



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