The 80/20 rule of running was first popularized by Dr. Stephen Seiler, a sports scientist at the University of Agder in Norway. Seiler’s research showed that elite endurance athletes, such as marathoners and triathletes, tend to spend 80% of their training time at a low intensity and 20% at a high intensity.
Seiler’s research has been supported by other studies, and the 80/20 rule is now widely accepted as a sound approach to running training. There are a few reasons why the 80/20 rule works.
Why does the 80/20 rule work?
There are a few reasons why the 80/20 rule works. First, running at a low intensity helps you build your aerobic base. This is the foundation of all endurance training, and it’s essential for running fast. When you run at a low intensity, your body is able to use fat as a fuel source, which helps you conserve glycogen (stored energy) for when you need it most.
Second, running at a low intensity helps you improve your running economy. This is the efficiency with which you use energy when you run. The better your running economy, the less energy you’ll need to expend to run a certain distance.
Finally, running at a low intensity helps you recover from hard workouts. When you do a hard workout, your body needs time to rest and repair itself. If you don’t give your body enough time to recover, you’ll be more likely to get injured.
How to follow the 80/20 rule
The 80/20 rule is easy to follow. Firstly we need to find a measure of intensity that works for us.
There are three ways to measure running intensity: pace, heart rate, and power. Each metric has its own advantages and disadvantages.
- Pace is a performance-relevant variable, meaning it is directly related to your running speed. This makes it a good choice for runners who want to train based on their race pace. However, pace can be unreliable when running uphill or downhill, as the terrain can significantly affect your speed.
- Heart rate reflects your physiological intensity, or how hard your body is working. This makes it a good choice for runners who want to train based on their heart rate zones. However, heart rate can be a lagging indicator of intensity, meaning it may not accurately reflect your current effort level. Additionally, heart rate can be affected by factors such as temperature and hydration, which can make it difficult to use as a reliable measure of intensity.
- Power is a measure of your running output, or the amount of work you are doing. This makes it a versatile and accurate way to measure intensity, regardless of the terrain or environmental conditions. However, power is not as widely used as pace or heart rate, so it may take some time to get used to using it.
The best way to choose your preferred intensity metric is to consider your individual goals and preferences. If you are training for a specific race, then pace may be the best choice for you. If you are more concerned with your overall fitness, then heart rate or power may be a better option.
Here is a table that summarizes the advantages and disadvantages of each intensity metric:
| Intensity Metric | Advantages | Disadvantages |
| Pace | It’s easy to adopt and easily comparable to other athletes. | Unreliable on when the terrain and conditions aren’t consistent |
| Heart rate | Reflects physiological intensity and takes into account other stressors. | Lagging indicator which can be affected by external factors |
| Power | Versatile and accurate | Requires a power meter or lots of math. Also takes time to get used to. |
Don’t have a fancy sports watch? Use the Talk Test
The talk test is a simple way to gauge your running intensity. It is based on the idea that if you can comfortably talk while running, then you are running at an easy pace. However, if you can only speak in short bursts or not at all, then you are running too hard.
To use the talk test, simply start running at a comfortable pace and see if you can talk in full sentences without gasping for breath. If you can, then you are running at an easy pace. If you can’t, then you need to slow down.
The talk test is a useful tool for runners of all levels. It is a simple way to make sure that you are running at the right intensity for your fitness level and goals.
Here are some other things to keep in mind when using the talk test:
- Your ability to talk will vary depending on the terrain. It will be more difficult to talk when running uphill or on a treadmill.
- Your ability to talk will also vary depending on your fitness level. As you get fitter, you will be able to run at a faster pace while still being able to talk.
- If you are new to running, it is a good idea to start with a very slow pace and gradually increase your speed as you get fitter.
How do I split my training 80/20?
Secondly, we need to identify the portion of your training that will be at an easier pace. A very basic way to do this is to simply divide your weekly running mileage by 5 and that’s how many easy runs you should do. For example, if you run 30 miles per week, you should do 6 easy runs.
Your easy runs should be done at a pace that you can comfortably hold a conversation. You shouldn’t be gasping for breath or struggling to keep up.
You can do your hard runs on the weekend or on a separate day during the week. Hard runs can include intervals, tempo runs, and hill repeats.
Here is an example of a training week that follows the 80/20 rule:
Monday: Easy run for 30 minutes
Tuesday: Hard run for 45 minutes
Wednesday: Easy run for 20 minutes
Thursday: Rest or cross-training
Friday: Easy run for 30 minutes
Saturday: Long run for 60 minutes
Sunday: Rest or cross-training
This is just an example, and you can adjust it to fit your own needs and goals. The important thing is to make sure that the majority of your runs are easy and that you only do a few hard runs each week.
If you’re new to running, it’s a good idea to start with a 70/30 split and gradually work your way up to an 80/20 split. This will give your body time to adapt to the new training load.
