Training intensity distribution

Notes on polarized and pyramidal training for beginner endurance athletes

marathon training is different.

If you’ve been following me for a while, you know I am a proponent of what some call polarized training.

And yet, I just came back from a 2-hour tempo run, all in the infamous “zone 3” (see image above).

Due to the different contexts in which the term polarized training is used (e.g. elite vs beginner athletes), and different interpretations of the term polarized, this can be a somewhat confusing topic.

This is unfortunate, as our failure to communicate something that is in fact rather simple, results in conflicting messaging for beginner or less experienced endurance athletes looking at ways to better structure their training or improve their performance.

In this blog, I’d like to spend some time trying to better convey this message to beginner endurance athletes. Let’s get better.

Terminology: zones, polarized and pyramidal training

I want to keep this section really light, so that we have the tools to understand what follows, without getting lost in a myriad of terms. Broadly speaking, we can break down training intensity distribution into 3 or 5 zones.

If we use three, we have an easy zone, a moderate zone, and a hard zone. The easy zone is below our aerobic threshold (first lactate or ventilatory threshold): think very easy, conversational pace. The second zone is below our critical power or speed (near the second lactate or ventilatory threshold): think some difficulty in saying a full sentence. The third zone is… well, hard.

If we use 5 zones, as it is often done, then zones 1 and 2 are the easy zone, zone 3 is the moderate zone and zones 4 and 5 are the hard zone.

Polarized training in the traditional sense means that more emphasis is given to the easy (1-2) and hard (4-5) zones, and less on the moderate one (3). An alternative would be pyramidal training, in which more emphasis is given to easy (1-2) and moderate (3) zones, and less on the hard ones (4-5).

Context: elite vs beginner athletes

The first source of confusion is often our own bias or the context we typically consider or deal with in our work.

For example, many will be quick at reminding us that elite athletes do not necessarily train polarized and that polarization might come only from high-volume training. It makes sense of course that if you train a lot, much of that training needs to be low intensity, or you would not be able to sustain it. Similarly, if we talk about long-distance endurance athletes (marathon, ironman, etc.), it also makes sense that much of the training is done close to the demands of the event, especially as we approach the goal event (this is the principle of specificity, more on this later).

However, when we try to communicate in a simple manner the benefits of properly structuring training to beginner endurance athletes, the context is dramatically different.

For most people, polarizing training means breaking an unproductive pattern: running always too hard, always doing the same type of training. Nobody is arguing for Kipchoge to stop doing his 40 km long runs near marathon pace. We are arguing for beginner athletes to better structure their training, and learn what it means to run easy.

When we look at the problem from this angle, it is a good idea to polarize more your training regardless of volume (total amount of hours in a week). This is just a first step towards learning to run easy.

But there’s more.

Beginners are different

For beginner endurance athletes, I do not think there is much of a distinction between polarized and pyramidal. Why? Because there is no well-developed aerobic base. Exercise intensity is much more binary at this stage: either you are going very easy, typically that’s near walking speed, or you are going hard.

The ability to sustain long, moderate efforts, in a stable physiological state, is just not there without a good aerobic base that normally takes years to develop.

Note also how the demands of the events are dramatically different for beginners: even if you build towards the long distance (say a marathon or ironman), the intensity is likely going to be the intensity of your easy training. A long event is moderate in intensity only for a small percentage of athletes. For the rest, even the principle of specificity says that it makes little sense to train at moderate intensity (when we are beginners!).

All of this points to the same direction: learn to run easy, so that you can recover faster, accumulate more volume, and make progress. Later, you can worry about polarized or pyramidal distributions.

Interpretation of the term polarized

When I talk about polarized training, I consider pyramidal a subset of polarized. This is exactly how Matt Fitzgerald has popularized the research, through his 8020 endurance work. We are not arguing to neglect intensities or neglect specificity, but to break the monotony and focusing on doing plenty of easy, low-stress training, combined with some higher intensity sessions.

Polarized training for us means that much of your training is easy, and the rest is not easy. Not easy can mean just a bit harder than easy (zone 3), or very hard (zones 4 and 5). It is a large spectrum of intensities, and you should pick what you need depending on your history, limiters, and target event.

But remember, beginners are different, and intensity is much more binary at that stage. Thus, the term polarized is in my view the most meaningful in this context. It matches their physiology, and is simple enough for prescription (go easy most of the time, go hard sometimes).

The point is still missed by many: polarized training is about not always training the same (which ends up being too hard for most beginners), it is not about avoiding intensities (zone 3 is totally fine!).

From beginners to experienced

Regardless of our athletic talent, we can all make huge progress in endurance exercise. In my view, as I often argue, a good place to start, for beginners, is to polarize more your training. This way we can break the unhealthy and stagnating pattern of always hard, always the same type of training.

This will lead to a positive cycle, as you will feel fresher after running (which will shift from too hard to easy), and this will in turn allow you to run more, bringing the additional benefits of higher volume.

At this point, once you have been training high volume for a little longer, have developed a good aerobic base, and your thresholds are getting where they should be (see Gordo’s great overview here), then it makes more sense to start being more nuanced about your training intensity distribution.

Here is where the non-easy training starts to take different shapes, which we can call polarized or pyramidal, depending on how much time we spend in zones 3, 4, and 5.

The demands of your event are key at this point. For example, a recent study led by Luca Filipas showed that starting with pyramidal training and then shifting to polarized was optimal for performance, but what was the target event? A 5 km time trial. In my training, I have done the exact opposite: started with polarized and then went full pyramidal, and what was my event? A marathon. Then, I went again pyramidal to polarized for a shorter race (10 km).

In all three cases, the principle of specificity applies: start with generic training, and get more specific as you approach the race, eventually running more time at or near race pace. This is nothing new or groundbreaking, but part of coaches’ wisdom for a long time.

Above is an example from HRV4Training Pro, where you can see my training intensity distribution in different training phases. The middle section, which includes more marathon pace, has plenty of zone 3 or moderate intensity, while the other training blocks are more polarized, in the traditional sense. These are approximations, based on average heart rate during exercise, but hopefully, you get the point.

Takeaways

When I try to communicate the importance of a meaningful training intensity distribution to the ones that I believe need it the most (beginners!), polarized is in my view the most meaningful term. It matches their physiology, and is simple enough for prescription (go easy most of the time, go hard sometimes).

This is why I stick with this term, even though I understand that training intensity distribution is more nuanced, and my own training clearly reflects this (depending on how far is the event, current fitness, weakness and strengths as well as the demands of the event, intensities will change, as shown in the figure above).

It should not be so difficult to find common ground, if we care about helping others and communicating the relevant aspects, more than winning some stupid debate or wasting our lives on terminology.

To sum up:

• Try not to get lost in terminology. Learn to run easy, and to do that most of your time. Easy means conversational pace, or low heart rate, and might require some walking breaks if you just started with endurance exercise. Mixing easy and hard will break the monotony of always doing the same thing, and likely bring additional benefits. Give it 4-6 months with high consistency and compliance, and you will start seeing improvements (your effort will be lower at a given pace or your pace faster at the same effort).

• As a beginner, training intensity is often rather binary, either easy or hard. As we start polarizing more our training, the easy runs will allow for faster recovery, which in turn will allow for more volume, which will lead to additional benefits, improving our fitness. Otherwise, we are not going to be able to get there if we are always tired from too hard efforts.

• Once we have developed some fitness and a better aerobic base, training intensity distribution becomes more nuanced, with time spent in different zones increasing or decreasing depending on the time of the year (e.g. how far from the goal event), current limiters, and the demands of the goal event (principle of specificity).

Take it easy!

Other resources

• 8020 training for beginners, my case study

• Combining polarized and pyramidal training, another case study of mine

• My training log for 2023

Marco holds a PhD cum laude in applied machine learning, a M.Sc. cum laude in computer science engineering, and a M.Sc. cum laude in human movement sciences and high-performance coaching.

He has published more than 50 papers and patents at the intersection between physiology, health, technology, and human performance.

He is co-founder of HRV4Training, advisor at Oura, guest lecturer at VU Amsterdam, and editor for IEEE Pervasive Computing Magazine. He loves running.

Twitter: @altini_marco

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