How Far to Go on a Marathon Long Run

Audio Transcript

Coach Sinead: Hi everyone. Today, we have a really great question about the marathon long run. I’m excited to answer this one.

Questioner: While marathon training, how far should your longest long run be and why?

Coach Sinead: This is a fantastic question, one we get pretty often at RunnersConnect. I think it’s a question that is surrounded by a lot of false information.

A lot of runners feel like they need to pack a lot of 20 to 22 milers in our training segment.

This is reasonable because you feel like you really need to put that work in so that you are both mentally and physically capable of going the distance on race day. I can definitely see the thought process there.

That said, the reality of it is that you just don’t need to do this. You shouldn’t do this because packing in, multiple runs of upwards of 20 miles in your marathon build-up starts to do more harm than good.

It inhibits your ability to improve more critical physiological systems. Not only that, but you’re putting your body at a greater risk for injury and you’re also just doing more work than you need to.

I don’t feel like too many people want to do more work than they have to in a marathon build-up, and scientific research shows that runs of over three hours offer very little aerobic benefit compared to runs of two hours.

This is where we feel at RunnersConnect that there is way too much emphasis placed on the long run in a marathon build-up.

There are so many different elements that contribute to your success at the marathon, and by overemphasizing the long run, you’re actually doing yourself a disservice.

This again is because you are increasing your risk for injury, and you’re also increasing your recovery time, which means you’re not able to attack your marathon-specific workouts later in the week, and you’re just not able to recover and build off each workout progressively as a marathon build-up should.

By trying to fit in multiple long runs of 20 miles and more into your training segment, you’re sacrificing your body’s ability to improve on other physiological systems, critical to marathon success.

One of these systems includes your aerobic threshold, which you help to build through these marathon-specific workouts, like tempo runs and steady state runs; any sort of long interval workouts.

Those really help to improve your aerobic threshold.

Another physiological adaptation essential to the marathon is your body’s ability to use fat as a fuel source.

This one is extremely important in those later stages of the race when you have become significantly glycogen-depleted, and your body has to switch over to using fat for energy.

The last big adaptation I’ll talk about is your body’s overall tolerance for running on tired legs through accumulated fatigue.

A lot of runners put so much emphasis on the marathon long run, that a lot of the times they end up sacrificing some of these other benefits that are crucial to marathon success.

I will say that the marathon long run really does depend on the runner, and the runner’s experience as well.

For these elite marathoners who have been running for years upon years, these guys have really worked all these other physiological systems, and they accumulated a lot of strength throughout these systems.

They’ve got a good foundation on which to build on, and they can afford to go on these lengthier long runs without sacrificing these other systems, and also putting themselves at risk for injury.

On the other hand, for the average runner and especially for the beginner runners, the marathon build-up is going to look a bit different.

The average runner and most of our members at RunnersConnect, run somewhere between 9 to 12 minutes per mile on their long runs.

You take a 21-mile long run, that would take somewhere between three hours and forty five minutes to five hours to finish a long run of that distance.

While there is no doubt that a long run of maybe twenty one miles would be a great confidence boost, it would definitely give you confidence, going into the marathon, that you are physically and capable ready to run the distance.

It’s going to do you more harm than good from a physiological standpoint. This is because studies have shown that your body doesn’t see any real significant increase in aerobic development, especially your mitochondrial development, when running over ninety minutes.

The majority of your physiological benefit from long runs occurs between the sixty to ninety minute mark.

What that means is that after running for three hours, your aerobic benefits, like your capillary-building and your mitochondrial development, aren’t going to be significantly better than when you just run for two hours.

Again, you don’t want to have to do more work than you need to, and you also don’t want to increase you risk for injury and increase your recovery time.

Studies show that running for longer than three hours significantly increases your chance of injury.

This is because your form begins to break down, your muscles start to get weak, and this is where your body becomes extremely susceptible to overuse injuries.

I will say again that this comes back down to experience and physical capability. For a lot of beginner runners, often their aerobic capacity exceeds their muscular and skeletal system capacities.

What this means is that, while a lot of runners have the lung capacity, their bodies aren’t yet equipped to keep up with that aerobic [strength 00:07:54].

So again, not only is your risk for injury increased by doing all of these lengthy long runs, but your recovery time is also significantly increased as well.

A long run of three hours or more adds considerable fatigue to your legs and this inhibits your ability to hit your target times, and a marathon-specific workout later in the week.

Research shows that these workouts are more important to marathon success than long runs.

This is because you’re improving your aerobic threshold, which is the fastest pace you can run aerobically and burn fat efficiently.

It’s also because you are benefiting from accumulated fatigue. This means that you are preparing your body to handle the full 26 miles that you’re going to be racing on race day, but you’re doing so without having to run the full distance in training.

This is why you should spread out your workouts and mileage over the course of the week, instead of having 40 to 50% of your weekly mileage come from the long run.

This significantly increases the quality of your runs, decreases the chance for injury, and also lets you accumulate the fatigue you’ll experience on your legs on race day.

However, you do so in a healthy way that doesn’t require you do more work than you have to.

To answer your question today, we recommend that you keep your long runs between sixteen to eighteen miles, but you’ll juxtapose it against a shorter, steady-paced run the day before.

What this will do is help simulate that fatigue you’ll experience at the end of a marathon, and it also ensures you’re recovering in time to take full advantage of your aerobic threshold workout later in the week.

Developing your aerobic threshold is the most important thing you can do in preparation for a marathon, because it lowers the effort required to run goal pace.

It also teaches your body how to conserve fuel so that you avoid bulking at the end of a marathon.

In short, you always want to focus on quality over quantity, and that’s why we recommend you do no more than sixteen to eighteen miles on your long runs in preparation for a marathon.

This ensures you’re getting all the physiological benefits from your other workouts and you’re not leaving your race in your training.

Thank you so much to our questioner today and thank you for listening in. I hope this podcast has helped you. If you have a question you would like to submit for one of our coaches to answer, you can go on over to runnersconnect.net/daily. Thank you so much again and I hope you have a great day.

Finally, sometimes it can be nice to take in your surroundings and be left to your own thoughts on a long, quiet run. Sometimes it can be pure agony.

I started running with music about a year ago and while it helps me get out the door and made solo runs more enjoyable, even music can get old especially when you’re exhausting your playlist every third run.

Podcasts like this one definitely help spice things up, but it’s hard to beat a good book when you’re logging mile after mile training for a marathon.

That’s why I decided to give Audible a try and I’m so glad I did. It’s got a ton of great running-related books to keep your mind off the run, and adds some comedic relief during those inevitable rough patches.

They expose you to new insights on training, nutrition, and mental gain. I’m currently listening to Once a Runner and it really gets me pumped to go for a run even when I’m tired, because it means I finally get to listen to the next few chapters.

The other cool thing about Audible is the first 30 days are free, which gives you a chance to try it out and see if it’s for you. Check out Audible’s extensive library and start your first month free at runnersconnect.net/audible.