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Polarised training for runners

Polarised training for runners

Back in the 2000s, Stephen Seiler, a professor in Sports Science at University of Agder, Norway, started to investigate more about endurance training structure and intensity distribution by observing the training routine of elite athletes such as cyclists, rowers, XC skiers and distance runners. Seiler realized that more than 80% of their training time was dedicated to low-intensity exercises, with very light effort. The remaining percentage was dedicated to work at a very high intensity level. In summary, when they were training easy, they would go very easy. But when they had to train hard, they would go really hard.

Over the years, other researchers corroborated with Seiler's first findings to describe the training methodology of intensity distribution, known today as polarised training model.

The essence of polarised training is to do 80% of training sessions at easy effort and about 20% or slightly less at hard effort, with relatively very little moderate effort in between.

It is a common mistake for amateur runners who train without proper guidance to spend most of the time training at high intensity, seeking high speed averages, always looking for doing impressive workouts. In times of social apps like Strava, each training becomes a competition. Sequential hard training sessions without light runs in between could give a false idea that it is the best way to achieve great performance. In the short term, it can give you a feeling of satisfaction and the illusory certainty that you are getting your job done. However, in the long term, training always hard can lead to plateaus and performance limitation or even decreased performance due to lack of recovery and overtraining.

Training zones

Before understanding how polarised training works in practical means, you need to understand how your body works during exercise. The first step is to identify training intensity levels. Several training guidelines use a multi-zone approach to set intensity levels, generally from 1 to 5, whether in heart rate or power levels. However, many studies have followed the principle of using three zones for polarised training, simply explained by the chart below:

Heart Rate


Perceived Effort (1-10)

Low intensity

<77% max HR


1- 4

Moderate intensity

77–92% max HR

You can speak in short sentences

5 - 6

High intensity

>92% max HR

Breathing hard after a few minutes of effort

7 - 10 

Low intensity is above the ventilatory threshold, lactate threshold or aerobic threshold and corresponds to the level of effort at which breathing is slow, there are no great muscle demands and there is a sense of easy workout. You could maintain this effort for several hours. It is the intensity most commonly used by athletes in endurance events such as long-distance triathlon or ultra running races, the effort that you would normally use for a recovery workout.

High intensity is the level of effort above the anaerobic threshold with hard rate of perceived exertion, high respiratory rate, which means you cannot keep a conversation during running, and the well-known sensation of burning legs. This is the type of effort that you could maintain for about an hour.

Between both, you will find the moderate intensity. It is neither easy nor too difficult.

Implementing polarised training method in your training routine

Firstly you must have an overview of your weekly training routine, including total hours of running to know how much time you will spend on easy runs and how much time you will spend doing high-intensity workouts. If you run 10 hours per week, you will basically do 8 hours of low-intensity runs and 2 hours of high-intensity workouts.

It is a very good idea to use a heart rate monitor on each run to make sure you are doing your workouts in the right training zone. Test your zones regularly, so you know they are accurate.

Following the principle of polarised training, high-intensity workouts must be really intense. If you can perform what you consider hard workouts day after day with no need to recover, you must understand that you are not doing workouts hard enough under the polarized training perspective. High-intensity workouts follow some basic guidelines. They need to be specific, at the correct intensity, with the right duration and recovery period.

Training in low intensity is about making your aerobic energy system more efficient. You teach your body to work for a long period with unnecessary energy expenditures that could compromise your performance. You optimize the mechanisms of fat metabolism which improves oxygen transport to your muscles, reduces the rate of lactate formation, improves the rate of lactate removal and increases energy production. Your body becomes more efficient to break down and utilize fat as energy source. Those physiological adaptations are especially important for long-distance events.

It also increases the number of mitochondrias, responsible for oxidative metabolism, providing energy from fat to your muscles in the presence of oxygen.

Although it is a light effort, it is not a "walk in the park", so you must focus on your cadence, breathing, consistent rhythm and running form. Doing runs in low intensity requires discipline and consistency. Nevertheless, your body adaptations will lead you to higher power and speed and, over time, you will find great improvements in endurance, recovery and performance.

Training in moderate intensity has shown to be not intense enough to stimulate positive physiological adaptations, however, it is still intense enough to accumulate fatigue and delay recovery. Athletes who spend a lot of time training in that level of intensity are more likely to feel tired all the time, struggling to properly recover and have limited gains in terms of performance.

Low-intensity workouts should precede and follow hard efforts and that is especially important for age group runners who need longer recovery periods between high-intensity sessions. Make sure that your easy runs are easy enough, so you feel fully recovered from hard workouts.

Even though you will be running slowly most of the time, there is some solid evidence that a polarised methodology approach is very effective in maximising positive results. Sports scientists suggest that high-intensity activity promotes significant changes in the muscle cells biochemistry and that seems to be even more effective when it is combined with a well-built foundation of aerobic training. Soon after adopting this training approach you are going to notice a decrease in overall fatigue, an increase of comfort in high-intensity zone and as a result an increase in performance.