Polarized Training for Runners: Why 80/20 Training Works So Well

Your hard runs should be hard. Your easy runs should be easy. If you feel like you’ve been kicking your heels without much progress, you might want to adopt a polarized training model — a popular training approach used by endurance athletes including cyclists, triathletes, and runners.

Polarized training for runners limits time spent training at moderate intensities and instead focuses on running at a very low or high intensity.

Traditional threshold, high training volume, and higher intensity endurance training models often result in overreaching, overtraining, and burnout, as noted in a review in The Journal of Strength and Conditioning Research amongst all levels of athletes.

By eliminating time spent in the “gray area,” each training session serves a purpose without making too big an inroad into your recovery ability.

Simply put: Your easy sessions are easy, and your hard sessions are hard.

Keep reading to learn:

  • how the polarized training method works for runners
  • how effective it is compared to other training methods
  • how to try it yourself

Two women running in the park at a slow pace part of polarized training.

What is the polarized training method?

Polarized training is a mix of low volume, high intensity training, and high-volume, low intensity exercise. This mix of intensity allows the body to compensate and adapt to training for long-term results in a sustainable way.

But what are we polarizing?

In an interview with Fast Talk Laboratories, sports scientist, professor at the Norwegian University of Agder, and one of the biggest proponents of polarized training, Dr. Stephen Seiler mentioned that “polarization of the stress of the daily training sessions” is imperative.

In other words, it’s about finding the right balance of stress to facilitate the required adaptations to improve performance without impacting recovery too much.

High intensity running (e.g. VO2 Max efforts and 800m repeats) performed too often increases your risk of burnout, injury, and overtraining.

It’s generally accepted that 80% of your training should be performed at low intensity and 20% at high intensity to best balance stress and training adaptations.

Heart Rate Zone Training 101

In order to fully comprehend how polarized training works, you’ll need a general understanding of different heart rate zones.

  • Zone 1: This is the lowest Lactic Threshold zone. Less than ~2 mmol of lactate is produced in this heart rate zone. Think of this as very easy running, a warm up, or cool down.
  • Zone 2: This is the lactic threshold zone between one and two. You’ll see between 2 mmol and 4 mmol of lactate produced during this type of training. And, because we know you’re not in a lab getting a VO2 Max test, the easiest way to find your Zone 2 is with a Rate of Perceived Effort (RPE) of 4 or 5 out of 10. You should be able to hold a conversation at this effort.
  • Zone 3: Above the Lactic Threshold 2. This should be a harder intensity effort.

For a more comprehensive guide on heart rates, we’ve created a guide on heart rate zone training for runners.

How does polarized training compare to other endurance sports training methods?

One study by Dr. Seiler and colleagues investigated the impact of training intensity distribution on 30 recreational endurance runners. Participants were assigned to one of two groups:

  1. Low intensity, polarized training 
  2. Moderate high intensity (between thresholds) 

Results after 10 weeks showed both groups significantly improved their 10km time but the best results were attributed to the polarized training model.

These results suggest greater training improvement effects in recreational runners.

A second study from Dr. Seiler et al. also compared the effect of two training programs, differing in intensity, on sub-elite endurance runners.

Study participants were also assigned to one of two groups:

  1. Low intensity (sub-threshold Zone 1 training)
  2. Moderate-high intensity (Zone 2 training)

The runners completed a 10.4km cross country race before and after the 5-month training period.

Results showed significant improvements in the first group (low intensity training) when compared to the second control group as long as paired with high-intensity training.

In both cases, polarized training, compared with another training method, produced the better performance improvements.

A woman running on a sidewalk next to a body of water.

Polarized Training vs. Pyramidal Training

Polarized training and pyramidal training look similar at first glance.

They both emphasize a large percentage of running at low intensity — but they are slightly different.

In the pyramidal training model, athletes spend most of their time training at low intensity (the base of the pyramid). Moving up the pyramid, the middle consists of threshold and tempo runs at moderate-hard efforts. And finally, the top of the pyramid — where the least amount of time is spent — is devoted to hard training. This is your high intensity VO2 Max efforts and hill repeat sessions.

In the polarized training model, there is no middle section of the pyramid. Instead, there’s even more time spent training at a low intensity with little-to-no-time spent in the moderate intensity zone.

Think, polar opposites.

The hard sessions (the top of the pyramid) are harder than in the pyramidal model because there is no middle section. The polarized model requires you to run very easy most of the time with a few intense workouts built in.

So which training model is better?

There is more research on pyramidal training simply because it’s been around for longer.

But don’t discount polarized training — both models have their advantages. You just need to decide which approach you want to take to your training!

Pyramidal Training and VO2 Max

Within the past few years, VO2 Max has become more popular as an indicator of metabolic flexibility, cardiovascular health, and a predictor of longevity.

VO2 Max is a measure of the maximum amount of oxygen your body can use during exercise. Simply, the higher your VO2 Max is, the more physically capable you might be.

Dr. Peter Attia, author of Outlive: The Science and Art of Longevity, explains in this clip the best way to improve your VO2 Max is to spend 80% of your training time in Zone 2 (65%-75% of your max heart rate) and 20% of your training time with high-intensity interval training

What is the difference between polarized and threshold training?

Threshold training is an intensity. Polarized training is a training framework model. 

In a pyramidal training model, you would perform threshold efforts. In a polarized model, you could still perform these efforts — but typically, you limit time spent at a moderate intensity and instead perform harder sessions.

In a training plan/model that includes threshold efforts, you might spend 35-55% of your time in this moderate threshold zone and less time training at a low intensity. Polarized training, on the other hand, primarily focuses on running at a low intensity with few very hard sessions sprinkled in.

Why does polarized training work?

In the typical polarized training model, there are a total of three training zones as we indicated above.

  • Zone 1 is the lowest intensity; it’s below the lactate point turn.
  • Zone 2 is after the first lactate turn point but before the second.
  • Zone 3 is anything past the second lactate point. This is all high-intensity work VO2 Max efforts and short anaerobic sprints at lactate threshold.

If you were to train using the polarized approach, you would spend the bulk of your time in zone 1 doing easy, long, slow distance runs, done to build your aerobic endurance.

If you feel like you’re running too slow in this zone, then you’re probably still not running slow enough. It will take some practice to find that sweetspot in your slow pace.

Zone 2 is kind of a gray area. This moderate intensity zone — where it’s not easy but not as hard as zone 3 is thought NOT to provide the best training benefit. It produces too much stress and recovery for what you put into it.

Instead, those harder efforts that comprise roughly 20% of your total training should be done in zone 3. Those are the VO2 Max interval training efforts, hill repeats, and other hard runs. The harder you go into zone 3, the less time you can spend in it. 

For example, on the complete end of the zone 3 spectrum is an all-out sprint, maxing out threshold power. You can’t maintain that effort for 1 hour straight.

In other words, your hard sessions should be hard, and your easy runs should be easy. You want to minimize the amount of training in between these intensities. 

Who is polarized training for?

Polarized training is popular with elite endurance athletes and you’ll see it’s growing popularity in Ironman triathlon athletes.

This is because a tremendous amount of their training volume and training time is spent a low intensity, building up a resilient aerobic foundation with a low risk of injury.

This training model also works well for more experienced recreational runners, but not so much for beginners. If you’ve been running for a number of months or years, then adopting the polarized approach may be the adjustment needed to help you improve your running finish times.

To get the most out of it, you have to commit to training hard on your hard days and very easy on your other training days. This is what allows your body to make the necessary adaptations to become a better and faster runner.

Furthermore, polarized training might also work well for those who struggle to find the time to train. Your hard sessions are short and intense, and your easy runs are not too demanding. 

How to get started with polarized training

If you want to try polarized training, you might choose to take a few days off running before doing so. Otherwise, take it easy for a week or so to let your body recover from any moderate-hard runs you’ve done recently. This short break or “recovery week,” although not necessary before you begin, will reduce your risk of injury and ensure your body is fully recovered to start your new training block.

One of the easiest ways to train using the polarized model is to train to heart rate, especially for those low intensity sessions.

Use a heart rate monitor chest strap, such as the Polar H10 for the best results.

As a guide, aim for 60-75% maximum heart rate (MHR). So if your MHR is 196, your low intensity runs would be between 117 and 147 BPM. 

You can use heart rate (HR) for high intensity sessions as well. But be aware of cardiac lag — where your HR takes time to catch up to the intensity you’re running. For this reason, you may choose to run based on previous race results or an effort scale (e.g., 1-10). 

A man running on a track doing polarized training workouts.

Sample Polarized Training Workouts

Dr. Stephen Seiler, in the aforementioned interview, noted how all hard sessions fall into the same bucket: they are hard. Whether that’s a session of hill repeats, VO2Max efforts, or short all-out sprints.

However, we provide a few hard sessions for you to try below if you want to give the polarized model a go.

Before performing any of the hard sessions below, complete a very easy warm-up jog followed by stride and dynamic stretches. Similarly, after each session, perform a short cool down jog of no more than 15 minutes and static stretches.

Hard session 1 

Aim to run each effort at or above your current 5km pace. This is likely to be an 8/9 effort out of 10. The workout:

  • 4×5 minutes hard
  • Jog 2-3 minutes between each interval 

Hard session 2 

Aim to run these at your current 5km or 10km pace. These should be hard, but not as difficult as Workout 1. Aim for 6-8 effort out of 10.

The workout:

  • 4-8 mile repeats
  • Jog 1-mile recovery between each interval

You might need to build up to four repeats. Consider integrating this into other track workouts for your distance running. If you can only do two for now, work to increase this number as you get further into your training. Because it’s a longer session, you’ll also develop mental strength.

Polarized Training Summary

Polarized training focuses on running at a majority low intensity with fewer hard intensity sessions. There is very little, if no, training done in the moderate intensity zone.

To get the most out of this training model, follow a training plan. Furthermore, whatever you do, try to avoid that “gray area” where you expend a lot of energy and create inroads to your recovery ability but make very few aerobic returns for the work you put in.

Stick with it for a few months, and you’ll see results.

If you find that you’re at a training plateau and considering alternative training formats, consider a training app like Runna. Like an Olympic coach right in your pocket, Runna is the training app we recommend the most.


What is the difference between polarized and threshold training?

Polarized training is a model, whereas threshold is a training intensity. Threshold efforts usually fall into the moderate intensity category, whereas polarized mainly sticks to low intensity and high intensity runs. 

What is the goal of polarized training? 

The goal of polarized training is to maximize training adaptations by running either very low intensity or high intensity. The polarized approach avoids moderate intensity as this builds up fatigue and increases injury risk with little return.

How many hours for polarized training?

4-6 hours a week is a good starting point for polarized training. But there is no set number — find what works best for you!

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