Everybody that runs a marathon train over numerous weeks to get to run a marathon. All runners are different, and there are many other training plans when training for the marathon. Some have the longest run, as low as 16 miles, while some will be 20 and some will be 22. I will recommend what I believe is the best training plan later on in this post, but first, I will look at how many 20 mile runs before a marathon.
How Many 20-Mile Runs Before A Marathon?
Many runners have a fixation with the idea that they have to be able to run at least 20 miles before they run a marathon. The answer to the question of how many 20-mile runs before a marathon is a very subjective question. The answer to this will vary with experience, injury record, and the pace at that the runner is running the marathon. I will go through each of these in detail below, but first, I will give you an answer to this question.
I believe you don’t need to run 20 miles before the marathon once you get to the start line feeling fresh, with the motivation to push yourself when things are getting tough. If we suffer from burnout, we won’t be able to do this. Under experience, injury record, and pace below, I will explain in more detail.
Experience
Experience of marathon running varies from runners running their first marathon to runners running their 30th or more. Many novice marathon runners want to run one 20 miles before the big day. 20 miles for one runner will have a different effect on your body than another. Just because other people are running 20 miles before the marathon doesn’t mean you have to do it as well. As a novice runner, you need to listen to your body. Runners that have many marathons in their legs will often run 3 or more 20 miles, some of them even going to 22 or 23 miles.
Injury Record
If you are a runner continuously picking up injury after injury, running 20 miles as a training run is not an option. Much of your training will be on the bike or rowing machine to tire your legs before you do your longish run, which might only be 10 or 12 miles. If we force our legs that are susceptible to injuries to run long mileage week after week before the marathon, these legs are more likely to break down, finishing our marathon before we even start.
Pace
The pace or speed at which you will run the marathon significantly affects how many 20 miles you can run before the marathon. If you are a runner that can run the marathon in under 3:45, you will be more inclined to run more 20-mile runs than a runner that will take 5, 6, or 7 hours. When training for a marathon, runners are recommended not to spend longer than 3 hours on a training run as once we run longer than that, we are not receiving any benefits, and we are reducing our glycogen levels. When these levels are reduced, our running for the next 3 or 4 days is negatively affected.
Why Should You Run 20 Miles Before Marathon
There are many reasons why runners should run 20 miles before the marathon, including the following:
- develop aerobic capacity and efficiency
- help build our metabolic pathway
- durability and stamina
- experience how to fuel our body, have proper hydration and run at a pace you can maintain.
Should You Run 20 Miles Before The Marathon?
Now that we have decided to run 20 miles before the marathon, when should we run these 20 miles? We may not get the desired benefits if we run it too early. If we leave it too late, it may harm our race day.
When you are only doing one 20-mile run before the marathon, we probably should run it about three weeks before. If we are running two 20-mile runs, we should run the first one five weeks before the marathon and then step back the next week and run the last three weeks before.
Recommended Marathon Training Plan
There are many different marathon training plans available. Still, I think the best plan for runners interested in races from 5k up to a marathon is Daniels Running Formula.
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In Daniel’s Running Formula, he gives training plans for various race lengths. He also has charts that help you plan your marathon time based on the shorter race distance times. He has different plans for the marathon based on how much mileage you want to run each week. In my opinion, it is the most comprehensive running book.
20 Mile Run FAQ
Runners have many questions about the 20-mile run. I will answer a few of the most popular below.
What Does A 20-Mile Run Do To Your Body?
A 20-mile run is severe on our bodies; the severity depends on our pace. If we can do the 20-mile run in under 3 hours, it is less severe than if we are a runner, which will take 4 to 5 hours to complete. The longer we run over 3 hours, the greater the likelihood of picking up an injury. It is said that we don’t receive any benefit once we run past 3 hours and are only reducing our glycogen levels after that.
Our legs will tire after a 20-mile run, and our bodies must recover.
How Long Should I Rest After Running 20 Miles?
We should have at least 3 weeks of rest after running 20 miles. Most runners run this as part of a marathon training plan, so we generally start our taper after our last 20-mile run. A 20-mile run will be more severe on an inexperienced runner as they will never have run this distance before, whereas an elite runner will run 20 miles very often, and their body will get used to this.
Is Running 20 Miles A Lot?
Running 20 miles is a long run for anyone. Some runners will never get as far as running 20 miles, but others will run lots of 20 miles over their running lives. Even some runners that train for a marathon should not run 20 miles as their pace is too slow and will take too long to run the 20 miles, doing more damage than good.
How Much Water Do I Need For A 20-Mile Run?
When doing a 20-mile run, our body must be adequately hydrated before running. If you sweat when running, we need to replace all this sweat lost when running. Drinking 4-6 oz (118ml to 177ml) every 20 mins is recommended. It might be hard to keep drinking at this pace when doing a long run without running to the toilet. I use salt tablets to replace my lost salt when running.
How Hard Is A 20-Mile Run?
A 20-mile run takes a significant toll on our bodies. It will have different effects on different runners. As I have explained above, if running a marathon takes 5 hours or more, a 20-mile run may severely affect our training, making us extremely tired in the lead-up and during our marathon.
A 20-mile run will tire our muscles, drain our energy, and reduce our freshness for race day. In addition, when doing a 20-mile run, you are more liable to get injured.
Should I Eat Before A 20-Mile Run?
When planning what you eat before a 20-mile run, include plenty of carbohydrates in the days leading up to the 20-mile run. Maybe try your carb loading that is recommended for when you are running your marathon just for a trial run. For example, if running in the morning, get up a couple of hours before running and eat a light breakfast, such as oats, a banana, toast, or a smoothie, to allow time to digest. Avoid fiber, protein, and fat, which are slow to digest.
How Do I Prepare For A 20-Mile Run?
When preparing for a 20-mile run, we need to build up our mileage slowly over the weeks leading up to the 20-mile run. Fuel the body properly with food and water. Ensure you have eaten some carbohydrates before the long run. Know the pace that you need to run your 20 miles to enable you to complete it. Use the 20-mile run to prepare your marathon food and hydration plan. Practice using mantras that may help you on the day of the marathon. Don’t overthink it; just run with how you feel on the day.
Final Thoughts
We have examined how many 20 miles a runner should run before the marathon. We have looked at the factors affecting whether we should run 20 miles. These are running experience, injury record, and pace. We must listen to our bodies and only run 20 miles if it benefits our marathon training. Now we know what a 20-mile run does to our bodies and the benefits of a 20-mile run.
I have also answered some of the most frequently asked questions concerning the 20-mile run.
