One of the most frequent marathon training questions I am asked has to do with the “best” distance for the weekly long run. At first I thought everyone was obsessed with the long run, but I have come to realize that people are really asking me something entirely different, as in:

“How far do I need to run in training to be ready for a marathon?”

This isn’t some minimalist running craze; it’s a function of reality — mos people only have so much time every week to train. So when you reduce your training to it’s minimum, what’s the shortest distance to run in order to be ready?

There is no one answer to this question, but there are quite a few lessons to be learned.

The Difference isn’t in the Distance

While the long run is the “sexy” component of marathon training, it’s not the difference maker. Rather, the long run is the product of the other work that you have done to this point.

If you think of your marathon training as a pyramid building project, it’s easy to see how countless shorter runs combine to create the foundation of fitness that enable your long runs to happen.

So while we are debating that long run question, it’s easy to miss the point: run more frequently, not longer, to be ready. That’s the point of the first six to eight weeks of your marathon training — building the fitness and durability to be able to complete a long run.

Instead of worrying about one individual run, focus on your total weekly mileage:

You can run a 36 mile week by doing three six-mile runs and one eighteen-miler. But you can also run a 36 mile week by doing six six-mile runs. Option #2 requires less recovery and presents less scheduling friction.

If you are faced with the choice of having to choose between running long or not, I suggest you need to reframe your training. At the end of the day, all your body knows is that it ran 36 miles last week.

One Run Does Not a Marathon Make

The second half of reframing the distance question comes down to understanding the fitness and experience required to be able to complete a marathon. Focusing on the long run puts a lot of eggs in one basket: there’s pacing, nutrition, technique, form and fitness. In other words, the long run is equal parts physical and mental — that’s why you are getting a little stressed out by it!!

But no one has finished a marathon and said, “The only reason I finished today was because of that one long run I did four weeks ago!”

The secret to making it to the marathon finishline is the 12 or 16 weeks of consistent training. Logging four to five to six runs a week. Running through the weather. Through the scheduling conflicts. Running what you could despite what the training plan called for.

A twenty-mile long run is equal parts good and bad for your marathon training. It needs to be approached with respect, fitness and some serious planning. You earn the right to run that long by compiling several weeks of quality, consistent training. If you aren’t ready for that distance, you can split the long run and make it more manageable.

Plan Weeks Instead of Single Runs

Every year thousands of runners are unable to do their long run because of injury, illness or other factors. Yet there’s no mass exodus on race day, no empty corrals. Everyone still races because they can race — missing the long run, or _a_ long run is no reason to pack up and head home.

Before missing a long run, there’s a lot of anxiety and tension around what making the decision will mean on race day. But afterwards, whether the choice was yours or not to make, it’s easy to rationalize how that individual session won’t affect your race day.

I want you to frame your long run decision from that post-decision mindset: If it was already gone, how do you manage your training?

The best answer is to plan the rest of your week, instead of planning that one run. Think of it like planning a birthday party. You can put all your time and energy into baking the best Elmo cake in the world, but we all know that it’s the countless details (invitations, games, party hats, balloons) that build the experience. And more often than not, one or more of those elements will be what makes the day so special.

Run Long Based On Your Current Fitness

So in the spirit of making the best damn birthday party / marathon epxerience, here’s a quick equation to help you manage the long run component of your training.

Your Long Run Potential = (Total Weeks of Marathon Training) x (Average Weekly Run Volume) x (Mileage Factor)

The Mileage Factor is determined by your weekly average run volume:

• If you run 35 miles a week or LESS, then your Mileage Factor is .0625.
• If you run 36 miles a week or MORE, then your Mileage Factor is .0375.

So, if you are in Week Six of your program, and you are averaging 35 miles a week, your math looks like this: 6 x 35 x .0625 = 13.1 miles

If you are in Week Two and you average 30 miles a week, your Long Run Potential is only 3.75 miles (round it up to four!). The point here…you really aren’t ready for a long run!

If you are in Week Twelve and you have been averaging 45 miles a week, your Long Run Potential is 20.25 miles.

Please Note: Just because the math says you CAN run 22 miles doesn’t mean that you SHOULD. The point here is that quality, consistent training can prepare you to run long…the math is here to show you what you can do. If you’ve never run longer than six miles, putting up a 15 miler will be a challenge. Possible? Yes. A good idea? No.

How Do You Manage Your Long Run?

More often than not, beginner marathoners run too hard on their long runs and sabotage their race day performance (spoken from experience!). That’s an article for another day, but I hope you share with us your long run training experience. What’s your “target” distance, and why?