Training volume is about more than mileage

One runner does a 12 mile run on the weekend. The only other run he does is a 6 mile run on Wednesday night.

One runner runs 3 miles every day, except for a rest day on Sunday.

One runner does a 5 mile run Tuesday and Thursday, then she does a longer 8 mile run on Saturday.

A sprinter practices 3200 meters of reps plus 2 miles of warmup and cooldown jogging on Monday, Wednesday and Friday. On Tuesday and Thursday she does an easy 3 mile run. She takes the weekend off.

All of these runners run the exact same mileage every week (18 miles). Would you consider their training equal? Do you think they’ll all develop their running ability the same way?

More importantly, is it accurate to cast a firm judgment on the quality of their training largely based on the fact that they run 18 miles a week?

I would say not. And yet that’s the pedestal on which so many runners and coaches put weekly mileage.

I didn’t even mention the runner who logs 18 miles a week, but also does cross training between those runs. Or the runner who logs 18 miles a week, but ends several workouts with some functional strength training. In most cases I didn’t even mention the pace or intensity at which any of those miles were run.

And I certainly didn’t mention any of their recovery habits, their nutrition, the amount of rest they get, how active they have to be outside of training, what they do for work and how that impacts their training, etc.

I didn’t mention how long they’ve been running, their body composition, their strengths or weaknesses, their injury or health history, etc.


Now, that doesn’t make mileage irrelevant. Obviously, races are run at a specific distance and you need to be able to cover it. As you get beyond the 10K distance your ability to run a lot of miles in one go becomes more important, and mileage becomes a key factor in determining how well you can do that.

But not all mileage is equal. Not all mileage is run the same way, and our ability to run and bounce back from X miles of running depends so much on everything else about not just what we run, but what we do before, during and after every run.

The old Riegel Predictor was based on the traditional postulate that you are capable of running a certain volume of miles every week, and you could only increase that by about 10% without getting injured. On the plus side, it got a lot of runners to be careful about building up their mileage. But it also traps a lot of runners into not running as much as they may be capable of running.

See, the predictor and such traditional advice has to operate under the controlled assumption that all miles in question are the same. Anyone who has sprinted a few meters, and also jogged a much longer distance, can tell you that’s not true.

Likewise, the assumption is that your current weekly average is your exact running capability, and that going beyond 110% of that is a problem. An elite marathoner who takes a month off following a goal race will certainly take it easy on mileage coming back, but they can probably go from 0 miles to 110 miles (or whatever their typical training volume may be) in far less than the umpteen weeks that a Riegel style predictor would indicate.

Or, in a more down to Earth example, someone who ran 50 miles a week with no days off during training that took two weeks off after running a goal marathon… will come back running fewer miles for a couple weeks. But according to the predictor, their rolling 6-week average of maybe 25ish miles a week indicates they shouldn’t try to run more than 27-30 the next week.

However, if that person tried to run 50 easy miles the next week, their legs probably would not explode. They just finished a training cycle where they ran that much, even harder than easy, every week for months! If they, say, ran 7 miles easy every weekday and then a long easy 15 miles on Saturday (aka 50 miles), they’d probably be okay.

Now, as I mentioned above… all this makes a ton of assumptions about the person’s diet, lifestyle, etc… that they have all of this in order to allow for running these miles. If this person cut their calories in tandem with their mileage drop, I don’t know that they manage it if they don’t eat more. If this person suffered an injury in the race that they worked through to finish but it’s lingered, I don’t know that it wouldn’t affect their running. If this person doesn’t do any speedwork, then maybe none of their miles are easy, and so the Predictor might be more accurate in their case (aka 50 miles now might be too much!).

Maybe the weather really sucks that week, and 50 miles is a problem if there’s a torrential downpour, or it’s -15°F outside!

Maybe this runner has a lot going on at work, and the stress is higher than usual, or the kids are sick (or (s)he’s sick!), and 30 miles would be too much right now, let alone 50.


That’s a lot of concepts to unpack for one post, I realize. And I can always come back to them in more detail later. But basically,

– Even if the miles are the same, the quality of a training program can vary widely based on how they’re run, and how the runner handles themselves between runs.
– How many miles you can run isn’t a simple calculation. It depends a lot on what kind of runner you are, what you’ve done and are capable of doing, where you’re at in life now, and what kind of running those miles entail… not to mention your lifestyle and training habits as a whole.
– Predictors and metrics make a ton of base assumptions that are rarely true across the board for everyone. All of us come from different contexts, and we have to weigh those effects against whatever general rules exist.

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