Run Slow To Run Fast: Use The 80/20 Method To Run Faster

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One of the most common questions that every runner asks at one point or another is, “How do I run faster?”

Of course, everything with running comes down to numbers— in order to get a PR, you have to get a faster finish time, which means maintaining a faster pace throughout the race. What is simple in theory is difficult to execute, as many frustrated runners know that sometimes your progress in terms of becoming a faster runner is slow.

Most runners assume that the way to run faster is to do just that—run faster. In practice, this entails tackling speed workouts like interval sessions on the track, hill sprints, and tempo runs.

However, there are also prominent running coaches who believe that you actually need to run slow to run faster.

The 80/20 method of running embodies this very notion: run slow for 80% of your training volume and run fast for the remaining 20%. This approach can be thought of as polarized training, with the emphasis on the need to run slow most of the time in order to be able to run fast when it comes.

In this article, we will explore the popular 80/20 method of running and how the 80/20 method uses the idea of run slow to run fast.

We will cover:

  • What Is the 80/20 Method of Running?
  • Who Uses the 80/20 Method of Running
  • The 80/20 Method: Why You Should Run Slow to Run Fast
  • How to Do the 80/20 Method of Running
  • How Slow Should Your Easy Runs Be?

Let’s get started!

A person jogging on the beach.

What Is the 80/20 Method of Running?

The 80/20 method of running, also called the 80/20 rule in running, involves performing 80% of your training runs of volume for the week at a slow, easy, conversational pace, and performing the remaining 20% of your training volume at a hard effort or high intensity.

In this way, the 80/20 rule in running is a form of polarized training. 

Your easy days need to be easy, and your hard days need to be hard. The murky middle ground of “somewhat hard” is not where you want to land.

The primary purpose of the 80/20 method in running is to ensure that your body is fully recovering on your recovery days so that you are able to maximize your effort and performance on the hard days while simultaneously reducing the risk of overtraining and overuse injuries because your tissues have actually recovered.

Three people running on the road.

Who Uses the 80/20 Approach In Running?

The 80/20 approach was developed by Stephen Seiler, an exercise physiologist at the University of Agder in Norway, after decades of analyzing the training of elite athletes.

Seller noticed these elite endurance athletes all exhibited a similar distribution of their training loads, and a very polarized one at that—with about 80% of their training volume at a super easy effort and 20% very intense.

There was very little time spent in the middle.

The run slow to run fast 80/20 method of running was later popularized by Matt Fitzgerald and has been adopted by competitive and recreational runners alike, from distances from the 5k to the marathon and beyond.

A group of people running in the park.

The 80/20 Method: Why You Should Run Slow to Run Fast

If you are concerned that running such a significant percentage of your training at a slow pace will make you a slower runner, you are certainly not alone. 

The concept that you should run slow to run fast is definitely counterintuitive.

However, there are several ways in which running slower can potentially help you to run faster. 

Benefits of the 80/20 method of running include the following:

#1: Running Slow Improves the Efficiency Of the Aerobic System

Running slowly keeps your heart rate in the aerobic zone, which means that you are taking in enough oxygen through your respiratory system to meet the oxygen demands of your working muscles.

Your muscles have to generate ATP (cellular energy) while you exercise in order to sustain physical activity.

This energy can be generated through several different metabolic pathways, one of which is the Krebs cycle, or aerobic metabolism.

People running over a bridge.

Both fat and glycogen (stored carbohydrates) can be broken down to create energy through aerobic metabolism.

The benefit of generating energy through aerobic pathways is that the metabolic byproducts do not “pollute” your muscles or cause fatigue

This is in contrast to what occurs with anaerobic glycolysis, an energy-generating metabolic pathway that occurs when your muscles aren’t getting enough oxygen.

If you’ve been running for some time, there’s a good chance you’ve heard of “lactic acid buildup” in your legs.

And, while this is a bit of a misnomer (it’s not actually lactic acid accumulating in your muscles but rather an increase in hydrogen ions), what people are referring to when they cite this lactic acid buildup is the detrimental metabolic byproducts of anaerobic glycolysis that cause a burning, painful feeling in your legs and extreme fatigue.

Essentially, when the muscles produce energy in the aerobic zone, you won’t have any acidic buildup in your muscles, so you can keep running comfortably and for much longer.

Running slowly improves the efficiency of your aerobic system due to adaptations such as increases in capillary and mitochondrial densities in your muscles, increases in the strength and chamber size of your heart muscle, and increases in blood plasma volume. 

As a result of these adaptations to aerobic training, your heart and lungs are better able to take in and circulate more oxygen at higher workloads, and your muscles and tissues are able to extract and use the oxygen to generate energy aerobically.

The more efficient your aerobic system becomes, the faster and longer you can run without getting winded or needing to produce a significant percentage of energy from exhaustive anaerobic metabolism.

A close-up of someone's shoes while jogging.

#2: Running Slow Reduces the Risk of Injury

When you run slower, there is less strain on your muscles and connective tissues and less stress on your bones and joints. The ground reaction force decreases at slower speeds, and your stride length shortens.

These changes decrease the risk of injuries.

#3: Running Slow Reduces the Risk of Overtraining and Allows You to Actually Run Fast

One of the primary problems with running in the middle zone—the moderately hard gray area between easy and hard—is that it’s not easy enough to allow your body to actually recover.

As such, runners who run their long runs and easy runs too hard are always flirting with the risk of overtraining because the accumulated fatigue drives the stress up in the body.

Let’s say that a hard workout takes you from feeling 100% down to 60%. A full recovery doesn’t occur unless you’ve bounced back to nearly 100%.

If your recovery run the day after the hard workout is run too fast and or is too intense, instead of coming back to 90-100% or so, you might recover only to about 80-85%.

This is problematic for two reasons: it decreases potential performance and increases the risk of overtraining. 

If you’ve only recovered to 80-85%, when it’s time to do the next hard speed workout, your body will already be starting at a reduced capacity–you only have 80-85% of your effort to give to the workout, instead of nearly 100%.

This means your ability to run as hard or as fast during the workout is impaired, which impedes your potential performance gains.

In practical terms, if you’re supposed to be running 6 x 1,000 at your 10k pace, but you’re only able to muster about 5 reps, or you are falling 5 seconds off your pace for each interval, your body will not have as potent of a training stimulus for inducing positive fitness adaptations.

A person running fast on a dirt road.

By running your easy runs easily, you will actually have the strength and energy to maximize your hard workouts and nail the times you are striving for. Studies show that polarizing training indeed improves running performance. 

One study compared the effectiveness of four different approaches to training on improvements in aerobic capacity (VO2 max) over the course of nine weeks.

The researchers split 48 highly-trained endurance athletes (runners, cyclists, triathletes, and cross-country skiers) into one of four training programs: high-volume training, “threshold-training,” high-intensity interval training (HIIT), or polarized training (which is akin to the 80/20 method of running).

Out of all four approaches, the athletes in the polarized training group demonstrated the greatest increases in VO2 max, time to exhaustion, and peak velocity/power after the nine weeks.

In addition to affecting performance, if you only recover to 80-85% after the first workout because you did your recovery run too hard, your second workout might set you back to 50% instead of 60%.

Then, if you again run too hard for your recovery, you might bounce back to only 75-80%.

Over time, you’re wearing yourself down and increasing the risk of overtraining.

A person jogging and smiling.

#4: Running Slow Helps Your Body Become More Efficient At Burning Fat

Slow running causes favorable adaptations in fat metabolism, allowing you to run faster while still burning fat for fuel rather than carbohydrates.

At lower intensities of exercise, the muscles are able to burn fat to generate ATP (cellular energy) rather than rely more heavily on stored glycogen (carbohydrates).

Our bodies have a limited capacity to store carbohydrates in the form of glycogen, whereas even the leanest runners have enough body fat to fuel hours upon hours of exercise. 

Running slowly helps your body get better at burning fat and sparing glycogen, which can be hugely beneficial for marathoners as well as those looking to burn body fat.

A person on a track.

How to Do the 80/20 Method Of Running

Again, the 80/20 method of running involves running easy for 80% of your mileage or minutes (depending on your preferred style of workout accounting) and running hard for the other 20% of your mileage or minutes.

For example, if you run 30 miles per week (about 50 km), you will run 24 miles at an easy pace or easy effort, and 6 miles will be devoted to speed work.

Of course, it might not always be as simple as saying if you run 5 days a week, you should run 4 days easy and one day hard, as you may run a different number of days per week where the math isn’t as neat.

Moreover, even if you run five days a week, you might have two hard workouts, but the mileage accrued during warm-ups, cool-downs, and recoveries counts on the “easy” side of the 80/20 rule, not the “hard” side.

So, if your workout is 2 miles warm-up, 3 x 1 mile at 5k pace with 400m in between, and a 1-mile cooldown, you’ve run 3.75 miles easy and 3 miles hard.

A person running on the road.

How Slow Should Your Easy Runs Be?

Surprisingly, one of the hardest parts about following the run slow to run fast 80/20 method is actually running slow enough on the easy days.

We know the concept of the 80/20 method is that you need to run slow to run fast, but what is “slow”? How slow should your easy runs be?

The short answer is slow enough to feel really easy, which will probably feel impossibly slow at first.

Here are a few ways you can determine your pace for easy runs:

  • 90-120 seconds per mile or 60-90 seconds per kilometer slower than your goal race pace goal pace

In terms of goal race pace, for example, if you are training to run at 5k in 24 minutes (7:45 pace), your easy runs should be at 9:15-9:45 pace.

The run slow to run fast 80/20 method of running can be great for anyone who’s finding they aren’t performing as well as they think they should be based on their training. There’s a good chance you need to run slower to run faster!

To help calculate your heart rate zones for low-intensity training, check out our heart rate zone guide.

A person jogging on a track.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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