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October 29, 2010 / elodie kaye

Measure of a Season

The final race in a season is as much a test of the training approach I followed, as it is a measurement of my progress.  It’s also a crude check on my qualitative judgement.  Your feelings about the totality of your season are usually more trustworthy I’ve found, but sometimes a disappointing result turns out to be closer to the mark than you realised when you attempt to quantify it.  Here then, is one more number you can apply to that 16-week journey.

I use Jack Daniels’ VDOT metric as a sort of point system for judging the comparative value of whatever plan I followed, whether it was boilerplate from another source, a personal or online coach, or a random one of my own devising.  With some caveats, a training plan that stimulated a bigger increase in VDOT presumably worked better.  One convenient reason to use this particular system over others is that Daniels himself claims that a single VDOT unit increase every 4 – 6 weeks is attainable under an effective program.  Other coaches don’t go out on a limb like this, and farther down I’ll explain why.

Assuming for the moment that he’s right, an optimal 16-week marathon training plan could improve your performance in principle by a maximum of 4 VDOT points or roughly, 25 min. if you run 4:30 or slower.  As you’d expect, the improvement in race times represented by one VDOT point gets smaller, the faster you are.  For a 3:30 marathoner, an improvement of 15 min. represents the same amount of progress.  At the risk of belabouring his point, Daniels does not claim you can literally take 25 min. off your last spring marathon time.  He means you can improve your fitness by an equivalent amount from the moment you begin training. There is inevitable fitness loss in the weeks after a marathon due to the taper as well as the recovery.  (The taper boosts performance during the race but it hurts your fitness afterward, when it really doesn’t matter.)  For shorter races, taper and recovery are correspondingly less dramatic so fitness loss may be minimised.


It’s as simple as taking a 5K race time or time trial from early in your season, and plugging it into a VDOT calculator of your choice.  Take your final race distance and time, and do the same.  Subtract the first number from the second and round to the nearest whole VDOT.  This is your season’s harvest boiled down to one hard number.

This evaluation is only useful if you ran a race, or a best-effort time trial, before you began training in earnest.  I hate this part of the exercise the most; early in the season I’m not into putting myself through a lot of pain, which is what’s required for a good test.  Later on, I’m a bit more calloused about running hard.  On the other hand, a significant part of training is mental, and a training plan that gave you the confidence to push hard at the end of your season is a better one.

With race distances and times in hand, here are some online VDOT calculators:

  • Attackpoint – My personal choice for the clarity of the layout, but the input interface could be better.
  • Runworks – This one has interesting calculators to correct for heat, altitude and body weight, but apply with caution.
  • Donovan Rebbechi – A basic, clear interface that’s easy to use.


  1. A time trial at the end of May – (30:30 for 3M) = 29*
  2. A time trial in mid-July – (29:27 for 3M) = 30
  3. The first race in mid-August – (1:33:48 for 15K) = 33
  4. The second race at the end of September – (2:06 for 13.1M) = 34
  5. The last race in mid-October – (2:02 for 13.1M) = 36†

* For the sake of clarity, I rounded off the VDOT for each result.  If you’re doing it for yourself, preserve better accuracy by recording the full decimal value and round off after you’ve subtracted the first and last results for your net improvement.

The final race was only 3 weeks from the half-marathon before, but with a full taper.

Over 16 weeks of training from June to October, I gained 7 VDOT points which exceeds the maximum that Daniels thinks I could have reasonably expected.  That doesn’t make me a training genius, it shows that the plan I cooked up out of thin air, and changed on the fly from week to week, was good enough.  I probably would have had the same improvement with almost any half-marathon plan that didn’t injure me.

I don’t feel that training for a full marathon would have been equally beneficial.  Part of the reason I had good progress is because I chose a race distance that suited my strength.  Threshold running is an adaptation my body makes relatively easily and quickly.  Pure endurance comes to me more slowly; I wouldn’t have been as motivated or as encouraged if I’d chosen to develop that first.


Daniels is often writing to an audience of well-developed runners — people who have already achieved a high level of fitness, race experience, and are training for performance.  Even though I’ve been running for over 10 years and have learned to race competently, I’m not and never have been close to developed.  For the most part, I’ve been able to count on recording ever faster times for one or more race distances every year that I was able to train.  This is the mark of a runner who has lots of room for improvement.  Thoroughly developed runners have already fulfilled much of their potential, so they can no longer take PRs for granted every year.  This is chiefly why coaches don’t publish claims about how much improvement a runner can expect over a given time period.  The rate of progress is very sensitive to an individual’s starting point, their athletic and running history, biology, chosen race distance, and more.

Environmental conditions like heat, altitude, and wind, and hills can have a big impact on VDOT.  Some of the calculators referenced attempt to correct for these variables based on Daniels’ own findings, but performance in heat for example, is still highly individual.  There is little change in my VDOT from May through July, a span of almost 8 weeks probably because of heat.  The August result likely reflects full heat conditioning, in addition to the effects of training.  In general, the larger a runner you are, the greater your heat penalty.  All things being equal (which they rarely are) a 180 lb. man will slow down more than a 130 lb. man, but losing 10 – 20 lbs. is unlikely to make an appreciable difference.  As well, the heat penalty is greater if you are slower, or if the race takes more than an hour to run.

VDOT is an imprecise measurement. Some of the calculators referenced provide output to the hundredth decimal; do not believe in that implied accuracy.  A change of half a VDOT may or may not be real; in fact, I don’t put much weight in an increment of one full point unless it’s part of an overall trend.  Like all kinds of measurements, this one is subject to how skilled you are at taking the test, as much as how fit you are.  It’s best to mitigate some of the inaccuracy of the initial test, by repeating it monthly or preferably by running some races during training.  In this way, you’re able to see a pattern; this is far more reliable than a simple before/after snapshot, and potentially valuable in identifying where things may have gone wrong if your season falls short of what you’d hoped.

A bad day happens to everyone.  There’s a multitude of reasons why a final race fails to reflect all that you’ve achieved.  This analysis is just one of many perspectives on a total effort spanning months.  The technicality of it should not be mistaken for greater validity.

A good day occasionally falls out of the sky, and you are graced with swiftness and power that you were not aware of.  Be thankful and exult in it, but also keep one hand trailing on your humility.  Equally significant and rapid progress may not be repeatable from one season to the next.

Notes on Procedure:

To gauge your starting point you can use a fast workout in the absence of any early races or time trials,  but bear in mind that it will probably underestimate your fitness.

It’s best to choose a distance that’s short enough that endurance wasn’t a limiting factor for an early season assessment.  You must be able to run fast and hard throughout, so that you measure all aspects of your fitness: some each of endurance, lactate threshold, and anaerobic tolerance.  It’s possible to use any race or workout distance to measure VDOT, but you may not have had the endurance to race hard over a long distance.  Distances less than a mile aren’t very useful, unless your goal race for the season was a 5K.

A final observation:

My initial VDOT (29) corresponds to a marathon equivalent of 4:57.  My final VDOT (36) gives 4:10 as a prediction.  The difference in pace is almost two minutes per mile, and yet my easy paces over the same period improved only 30 – 45s.  This doesn’t reflect a deliberate effort to keep my daily running slow, it’s more a consequence of indifference.

All calculators and many coaches have told me for years that I could be running faster on a daily basis.  Maybe so.  However, it’s worth noting that my lackadaisical attitude didn’t significantly impede progress.  Of course, there may come a time in the future when it does — it just hasn’t happened yet.  Running a full minute faster for every mile would typically buy me only 6 minutes a day.  There’s precious few things I’d rather be doing for six minutes, than being outside soaking in the feeling of open air against bare skin, for what could be the last time in six months.  Some numbers capture more than others.


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