Polarized Training Guide: Focus Only On The Hard And Easy Workouts

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Runners tend to be driven, goal-oriented, competitive people so it’s only natural that most runners want to know how to get faster.

There are any number of approaches to training for distance runners, many of which are indeed designed to help you run faster. 

Some runners run high mileage at a very low intensity. Some runners try to incorporate a lot of tempo runs and threshold intervals into their training.

Another popular approach to programming your running workouts is known as polarized training. Polarized training involves focusing on keeping your easy runs easy and your hard runs hard and getting rid of runs that fall in the middle.

But, does polarized training work for runners? Should you only focus on hard and easy workouts?

In this guide, we will explore the benefits of polarized training and how to implement polarized training to your own running.

We will cover: 

  • What Is Polarized Training?
  • What Are the Benefits of Polarized Training for Runners?
  • How Do You Do Polarized Training?
  • Does Polarized Training Work for Runners?

Let’s get started!

A person running hard on a track, doing polarized training.

What Is Polarized Training?

Much in the way that the North Pole and South Pole are on the extreme ends of the planet, polarized training involves splitting your intensity levels for your workouts into two extremes—very easy and very hard.

In other words, if you practice polarized training, you run your easy days easy and your hard days hard. The murky middle is all but eliminated, or at least minimized to nearly nothing.

Runners who engage in polarized training typically use an 80/20 approach to polarized training, which means that they run 80% of their mileage at an easy, conversational pace and 20% of their mileage at a high-intensity.

For example, if you run 20 miles a week, you’d run 16 miles at your easy pace and 4 miles would be high-intensity work.

Polarized training for endurance athletes emerged about 20 years ago in response to the observation that most elite endurance athletes seemed to inherently be practicing this method.

In other words, elite athletes, who competed in sports such as running, cycling, and cross-country skiing, were seemingly spending the bulk of their training time doing low-intensity workouts, with some training time at a high intensity, and little to no time in the murky middle.

A group of people running on a track.

What Are the Benefits of Polarized Training for Runners?

Many runners fall into the trap of running roughly the same pace every day. 

At best, many runners who try to incorporate speed workouts and long runs do end up having some distinction between paces for different workouts, but the magnitude of the difference is compromised by the fact that recovery runs aren’t easy enough to truly allow the body to fully recover.

If, for example, a hard workout takes you from feeling 100% down to 60%, a proper recovery doesn’t occur unless you’ve bounced back to nearly 100%.

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

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

This, in turn, impairs your ability to run as hard or as fast during the workout, reducing your potential performance gains.

A person running and smiling.

In practical terms, if you’re supposed to be running 6 x 800 at 5k 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.

Proponents of this polarized training model argue that Zone 2 is not actually hard enough to effectively trigger the physiological adaptations required for improved performance, and also not easy enough to facilitate recovery or increase endurance.

Not only does falling into the trap of running almost every run at the same pace limit your overall progress, it can also lead to overtraining and overuse injuries, because the same stresses and intensities are placed on the body stride after stride, run after run. 

In contrast, runners that train at drastically different paces—running speed workouts and slow runs—introduce more variability into their stride and the resultant stresses on bones, muscles, and connective tissues. 

This can reduce the risk of injury and increase overall strength.

In sum, the main benefits of polarized training for runners include the following:

  • Allows you to maximize your potential to perform well in hard workouts, thus leading to more rapid and significant performance improvements.
  • Improves the ability to recover after workouts.
  • Reduces the risk of overuse injuries.
Two people running in the middle of a road.

How Do You Do Polarized Training?

Rather than the five different intensity zones used with traditional heart rate training, polarized training model divides training intensities into three zones.

Zone 1

Zone 1, the low-intensity zone, involves running at an easy, conversational pace that allows you to talk in complete sentences.

On a physiological level, Zone 1 would be any effort below your lactate threshold or ventilatory threshold, and typically corresponds to a heart rate of 70-75% of your maximum rate.

Zone 2

Zone 2, moderate-intensity running, is a “comfortably hard” level, where you can probably speak in short sentences.

This zone equates to your tempo run or threshold effort, and falls between your lactate threshold and critical speed.

In the polarized training framework, Zone 2 corresponds to a heart rate of about 80-85% of your maximum heart rate.

A person sprinting.

Zone 3

Zone 3, the high-intensity zone, is anything faster or more intense than your critical speed. 

When running in Zone 3, you will only be able to utter a couple of words at a time, or very choppy sentences.

Your heart rate when running in Zone 3 is above 85% of your maximum heart rate.

With polarized training in its purest form, athletes usually spend about 80% of their training time in Zone 1 and 20% of their training time in Zone 3, but polarized training has adapted to have several different iterations in distributions of training volume and zones over time.

Some coaches who still consider themselves practicing polarized training group zones 2 and 3 together, and therefore athletes do 80% of their training in zone 1 and 20% of their training in zones 2 and 3 combined.

Others morph polarized training further, by training 70% of the time in Zone 1, 20% of their mileage in Zone 2, and 10% in Zone 3.

This should be distinguished as pyramidal training, but the term polarized training is still often ascribed.

Two people running a park talking and laughing.

Does Polarized Training Work for Runners?

Studies have shown that polarized training for runners can be an effective way to improve performance and get faster over time.

For example, one study compared the effects of a polarized training program and more traditional running training program on 10k running performance over the course of 10 weeks.

The researchers split 30 endurance runners into one of two groups.

The polarized training group did 77% of their mileage in zone 1 (defined as an intensity below ventilatory threshold), 3% of the mileage was run in zone 2 (defined as an intensity between ventilatory threshold and respiratory compensation threshold), and 20% of the mileage was in Zone 3 (defined as high intensity above respiratory compensation threshold).

The “between thresholds endurance training” group ran nearly the same amount of mileage in Zone 3, but the distribution of training time in zones 1 and 2 were quite different.

This group ran 46% of their workout time in Zone 1, 35% in Zone 2, and 19% in Zone 3.

To quantify and qualify the type and time spent in each training zone, runners wore heart rate monitors and their exercise heart rates were compared to their baseline testing in which their ventilatory threshold and respiratory compensation thresholds, and associated heart rates, were identified.

After 10 weeks, both groups demonstrated significant improvements in 10k run times. Although not statistically significant, the polarized training group did improve more than the more balanced training group.

Runners in the polarized training group improved their performance by 5%, whereas the other group improved by 3.6%. 

This difference in improvements between the two groups equated to roughly 41 seconds, meaning that runners who had followed polarized training reduced their 10K run times by an additional 41 seconds over the other training group.

Moreover, when the researchers took a deep dive into which runners in the polarized training group had polarized their training most dramatically, those who had the least training time in Zone 2 had the greatest performance improvements.

A person running on a track.

Another 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.

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.

Polarized training increased VO2 max by 11.7%, time to exhaustion by 17.4%, and peak velocity/power by 5.1%.

Not only did polarized training yield significant improvements in endurance performance parameters, but the other training programs were found to not cause improvements in any of the variables measured.

If you find you aren’t making the improvements you’d hope to with your current training program, it might be worth following the lead of many elite runners and jumping on the polarized training bandwagon.

Although you don’t have to strictly do away with every tempo run or moderate-intensity workout, see if you start to feel fitter and faster if you focus on taking your easy days really easy and pushing yourself to the max in your hard workouts. 

To become familiar with all of the different types of running workouts, look at our All Types of Running Explained guide.

A person standing on the road, flexing her biceps.
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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