What's the point? Considering the various reasons to go for a run

If you know your physiology— or if you've read my book, Modern Training and Physiology—you can probably rattle off a number of reasons.  Increased red blood cell count, more mitochondria, deeper capillary beds, et cetera, et cetera.  All of this improves your aerobic capabilities, and this is why the first thing to do in order to get faster is to run consistently, and run more.

If you approach the question of why you should go for a run with the mindset of a complete novice, you'll realize there are some obvious points to consider.  How far should you run? How fast should you run? Should you run the same speed every day, and the same speed year-round?

"Going running" is the staple starch of a distance runner's training.  But I've come to realize that a lot of athletes can't articulate what purpose the plain old boring run serves in training.  They know VO₂ max, they know lactate threshold, they know marathon pace and critical velocity and hill sprints and creatine phosphate sprints and any number of other highly technical tools of training, but have only a vague inclination of the purpose of just going for a run.

Part of why this question is a little tricky to answer is because the standard run has a number of different uses.  This leads to confusion about how fast to run, how far to run, and so on.  In order to get a better intuition about the purpose of running generally, and easy running specifically, it will be instructive to look at the range of uses of the "regular run."

First, a thought experiment: If a total newcomer to the sport—say, a high school boy who runs 5:30 for the mile in gym class with no running-specific training—starts running 30 minutes at an easy effort every day, will he improve? Certainly, yes.  The new stress on his body will stimulate a physiological response in the form of improvements in the "oxygen delivery system"—all those physiological markers of performance that you read about in textbooks.

The same high school runner, a year later, decides to start training harder.  He still runs 30 minutes per day, but increases the effort level, running at a moderate to fast pace at least 4-5 times per week.  Will he improve? Again, yes.  Though the volume of training is the same, the intensity is higher.  This, again, creates a new, stronger stimulus on the aerobic system, which responds in turn.

Now consider an alternative: Instead of running faster, our runner decides to run 60 minutes per day, still at the same easy effort as before.  Will he improve? Yes.  A new and greater stimulus leads to a proportional increase in fitness.

Finally, a third situation: our runner, a year after starting his training program, decides instead to keep doing the same thing—running 30 minutes per day at an easy effort.  Will he still improve? Maybe a little bit...but eventually, his aerobic fitness will not get any better.  This is one mistake that die-hard Lydiard fans often make—believing that the same training (e.g. 100 miles a week) can produce improvements in aerobic fitness forever.

In reality, of course, high schoolers often do continue to improve year after year with the same training, because they're maturing and developing, which also contributes to performance.  And our simplistic thought experiment doesn't take into account the effects of workouts and races.  If your workouts are progressing over time, in volume, speed, intensity, or some combination thereof, you can improve your performances even if your off-season training is the same, but that's outside the scope of our topic for today.

So, we might conclude that the purpose of running—in the off-season at least—is to produce a new stimulus on the aerobic system in order to improve our fitness.  This is correct, but it's only part of the purpose of the easy (or not-so-easy) run in training.

Easy to moderate running also serves as a foundation for supporting faster or longer running later.  If one of your staple sessions during the cross country season is a six-mile tempo run with a two mile warmup and a two mile cooldown, you'll be able to run that session much better if you are accustomed to easy to moderate runs of at least ten miles.  Easy to moderate running also serves as a base for more easy to moderate running.  It's very hard (and often injurious) to run 70 mile a week next month if you haven't been running 50 miles a week this month.  Coaches often describe summer or winter running as "base work," and in this sense, it really is foundational—the more structured workouts you do later benefit greatly from a solid base of easy to moderate running. 

Understanding this puts some constraints on what kind of mileage is necessary for a given event, since the specific demands of each event dictate what level of support you need. 

For the 800m, the benefits of easy to moderate running are only distantly related to the demands of the actual event: running at speeds of seven or eight minutes per mile is worlds away from running 55-second 400 pace.  Still, some quantity of easy to moderate running is beneficial because it improves your ability to run shorter and faster in workouts. 

If you are an endurance-oriented 800m runner, a 60 minute easy run supports your ability to do a 40 minute moderate run, which in turn supports your ability to do 15-20 minutes fast, which ultimately leads to better performance in endurance-focused interval sessions, like 9x500m at 80% of 800m pace or 6x500m at 90% of 800m pace.  So, easy to moderate mileage can be useful to the 800m runner, but to insist that it's the most important part of training for this event is a big mistake.  For 800m runners, hundred-mile weeks are a thing of the past.  An 800m runner will never need to do a race-specific session totaling 15 miles of running, so 15 miles a day is not a productive or efficient use of training time.  It might "work," but better training works better. 

At the other end of the spectrum, we have the marathon.  This is an event of extreme extension: to build your body's ability to run 26.2 miles at a fast pace requires workouts that regularly total 18-24 miles of fast running.  The only* way to support this is a lot of easy to moderate running.  There's just no way you can have success with workouts like 5x5k at marathon pace with 1km of recovery at 90% of marathon pace if you're only doing an hour of running per day before you start marathon-specific work.  In this case, one hundred miles a week for a marathoner is low mileage—the race is 26 miles, so running 15 miles a day might not enable peak performance.

For now, we're ignoring the matter of recovery.  Some people are not capable of handling 120 or 140 miles a week without getting injured or succumbing to overtraining.  While you can tremendously increase your ability to recover with patient and gradual increases in training, there is a limit to the size of a training stimulus you can recover from—you can't keep increasing your mileage forever.  Even world-class marathoners typically top out around 130-160 miles a week.  So, your current ability to recover and adapt to training is another constraint you need to consider.  Training stress is (roughly) the combined effect of pace and duration—this is why many people, including me, recommend keeping the effort level on normal runs very easy when pushing up into new mileage territory, or when sustaining high mileage and a good bit of high end aerobic work too.  Even if the pace is very easy, high mileage still serves as a foundation for long, fast running later.  The same is not always true for lower but higher intensity running.

Individual recovery ability varies greatly from person to person.  Some division one teams run six-minute miles for every single run, while others keep the pace of many of their runs well over seven-minute pace.  You'll have to explore for a bit before you find out what's right for you.

*I've been thinking a lot recently about whether it's possible to run a good marathon with lower mileage (circa 70-85 miles a week).  The demands of the marathon surely necessitate high volume days, but perhaps not high volume weeks.  It may be possible to prepare for marathon workouts with, for example, a 75 mile week with the following structure:

5

7

12 / 6

12 / 6

4

5

18

Finally, we should consider the concept of the recovery run.  Many coaches and runners extol the regenerative properties of going for an easy run the day following a hard workout or a race.  This line of thinking dates back to the days when people believed that "lactic acid" (a misnomer; see Chapter 1 of my book for details
) sat around in muscles for hours or days following a hard session and needed to be flushed out.  While physiologists insist that lactate is cleared out of muscles very quickly following fast, anaerobic running, there's no denying the real-world evidence that an easy run does make you feel better after a hard effort.  I'll leave it to the laboratory scientists to figure out whether this is a psychological or physiological phenomenon.  In the case of a recovery run, the pace is not important.  Renato Canova recounts a story about 1:43.03 800m runner Kenneth Kimwetich, whose preferred method for recovering the day after an extremely tough workout was to run in the forest for three hours—at ten-minute mile pace! Though Canova knew that this wasn't the optimal physiological way to recover, Kimwetich nevertheless ran worse when he tried doing a more typical 60 minute recovery run.  So, for the recovery run, you must do whatever makes you feel better.

There's another lesson to be learned here: If the purpose of a run is primarily for recovery, you should consider whether going for that run is actually going to help you recover or not.  If you are sick, feeling a nagging injury, or have to travel all day, is going running at all going to benefit you? I've spent a lot of time reviewing the training logs of elite Kenyan runners, and one thing that surprised me was their sang-froid with regards to the inconveniences of travel.  Where an American might get up at 4am to sneak in a run the day of an international flight, or stay up late to go for a shakeout jog after arriving, Kenyans will just take the day off.  Often, Kenyans won't run for several days in a row because of how long it takes to travel to Europe, Asia, or America from rural Kenya!

To distill what we've learned in this sprawling article, let's bring our focus back to specifics.  If we consider a typical six-month training cycle leading up to a short period of important races (or one important race), what is the purpose of going for a run in each phase of training?

Primary purpose: Build up your body's ability to do more easy to moderate running

Secondary purpose: Increase your aerobic fitness

During the first phase of training, your focus is completely on preparing yourself for the real meat and potatoes to come.  As such, it is not particularly important, nor even desirable, to do very much of this running at a fast pace.  Yes, it provides a stronger stimulus, but the risk of injury will be higher if you start doing a lot of fast running without first building up your body's ability to run at an easy pace.

It's important to note that runners vary greatly in how much introductory running they need and how rapidly they can build up their mileage.  Some need only two or three weeks before they're right back in the swing of things, while others may need six or eight weeks of very patient, methodical increases in training volume and intensity.

Primary purpose: Increase your aerobic fitness

Secondary purpose: Build up your body's ability to do fast, high volume workouts

During traditional base work, your primary goal is improving aerobic fitness.  Because of this, when you go running, it's okay (and indeed, good!) to run at a moderate or fast pace.  A lot of runners get overexuberant about "keeping easy runs easy" during the base phase.  Obviously, if you are tired or worn-down, you should take it easy, but if you run solely at an easy pace for two solid months, you're short-changing your fitness later in the season.  Especially if you don't have a lot of scheduled workouts, your "easy" runs should sometimes morph into moderate runs or fast, high-end aerobic runs.  Not always, not every time, but at least once in a while.  If that's not happening, something's not going right with your training. 

The situation is a little different for a true 800m runner, but we'll leave that discussion for another day. 

(Semi)-Primary purpose: Recover from and adapt to race-specific workouts

Secondary purpose: Increase/maintain your aerobic fitness

Co-secondary purpose: Build up/maintain your body's ability to do fast, high volume workouts

The relative importance of your priorities during race-specific training varies from day to day.  For example, you might do a challenging interval session on Monday, so Tuesday's run serves mostly to recover from the previous day's workout.  But if your next scheduled workout isn't until Thursday, your Wednesday run can be at a steadier pace, serving to augment or maintain the aerobic fitness you built in the months prior.  Likewise, a long easy run isn't exactly regenerative, but rather serves to bolster aerobic fitness and support long, fast running later in the season.  For this reason, I've added the "semi-" and "co-" qualifiers.

Primary purpose: Recover from and adapt to race-specific workouts and races

Secondary purpose: Maintain your body's ability to do fast, high volume workouts and races

Tertiary purpose: Maintain your aerobic fitness

By the time the racing season has arrived, your marginal gains in aerobic fitness will be essentially nil.  This is why maintaining (and not building) aerobic fitness is relegated to a distant third in priority order.  It's still important to support your ability to run fast, which is why you do usually need to run something more substantive than a 20-30 minute shakeout every single day, but as you approach your most important races, recovery and adaptation are paramount.

You'll notice that regular runs have multiple purposes in all phases of training.  No type of training exists or acts in isolation—training sessions, even just going for a run, have a composite effect on your body.  While the main purpose of going running during the racing season might be to recover and refresh your mind and body,  you're also providing some aerobic stimulus and basic foundational work.  Still, this isn't the primary purpose of the run—that's why it's a bad idea to hammer the pace on a run the day after a hard workout, or to drag yourself out of bed for a run if you're sick the week of an important race. 

Hopefully you've come away from all of this with a better understanding of why "going running" is a basic necessity in any distance runner's training schedule.  When you understand why, you can more clearly apply the how—should I run fast today, or easy? Long or short? High mileage or low? Consider what we've learned in this article when you answer these questions.  Now get out the door and go running!