Polarised training with Stephen Seiler, PhD | EP#177
Stephen Seiler, PhD, is known for his research on how elite endurance athletes actually train. In this research, he discovered that most endurance athletes spend the majority of their training time (~90%) at very low intensities (below the first lactate/ventilatory threshold) with most of the remainder of the training time spent at high intensities (above the second lactate/ventilatory threshold), with little time spent in between. This training intensity distribution has become popularised and known as 'polarised training'.
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In this Episode you'll learn about:
- What is polarised training, and what is the evidence behind it?
- Polarised training and "pyramidal training" - the nuances of training for different kinds of endurance sports and events.
- Does polarised training work for time-limited age group triathletes?
- How to set up your training zones and intensities correctly (and the dangers of short-cutting FTP-tests).
- Triathlon-specific considerations with polarised training.
Overview of polarised training
- We know that if you want to be really good at endurance you have to train a lot - this is fundamental across the disciplines.
- We also know that we need some intensity, so the question is about how to balance these two aspects in a sustainable way.
- We've seen that what almost always characterises gold medal athletes is that they're doing a large percentage of their total volume training at a fairly low intensity.
It's usually below their first lactate turn point.
- We know that it's around 80% of their training sessions tend to be at this lower intensity, and if you measure time in heart rate zone it may be more like 90% of total time at lower intensity.
- Physiologically it's more useful to think in terms of sessions.
It's the entire period of time that will be changed by the stress response that you induce if you work at high intensity.
Certain says you may be trying to avoid triggering a big stress response, and just collect minutes with good metabolic flux and good signalling for adaptation.
- We see that elite athletes generally have tremendous intensity discipline.
- Sometimes it can be appropriate to use heart rate, but generally it can be good to put the training sessions in categories: low, mid and high intensity.
You can then add them up over time and check you're getting the distribution right.
Evidence base for polarised training
- I first started working on this because I was struck by observations I was making in Norway.
- I was then asked to be a reviewer of a study looking at elite Kenyan marathon runners.
What emerged when I looked at the data was that 80% of their km's were below marathon pace. 18% was faster, and a very small percentage was at marathon pace itself.
- At the same time, National team coaches in Norway coaching the best cross country skiers in the world who have huge VO2max values were saying working at threshold was 'too much pain for too little gain'.
- We then started collecting data to quantify what was happening in cross country skiers.
We started with juniors, but also had good case data from Olympic gold medalists with the help of the Norwegian Olympic Federation.
- We started looking at this across a number of disciplines and started to see a pattern: polarisation of training.
- In the early studies we did with skiers and rowers, there was a very clear polarisation:
There was a lot of training at low intensity, a good proportion above lactate threshold and very little at the threshold (zone 2 in a 3-zone model).
This is where I coined the term 'polarised model'.
- There are some groups where the distinction between time in zone 2 vs 3 isn't as clear, but there is always a big volume of zone 1 training.
How athletes solve the zone 2/zone 3 distribution varies on their discipline, technical issues with their sport etc.
- In a 5-zone model, this means 80% of sessions would be in zones 1 & 2.
Differing distributions of zone 2 & 3 work
- Rowers compete over 6-7 minutes, so their whole competition is at VO2max or above.
They are really polarised in their training, they don't do much threshold at all.
- Cross country skiers are also very careful in their training - they do a lot of low intensity.
They use a 5-zone model and tend to do a lot of zone 4 work.
- If you look at triathlon, particularly Ironman, we see the distibution being more pyramidal.
It steps down from 80% at low intensity, and maybe 10:10, or 12:8 percent at zone 2 and 3.
- It's important to note that we have done experimental work where trained athletes come in a do different sessions: either clearly in zone 1, zone 2 or zone 3.
We have then measured their recovery using heart rate variability to see how they recover from this type of work (e.g. 1-hour zone 1, 30 minutes of threshold work, typical intervals session etc).
We could not distinguish the recovery between zone 2 and zone 3 - in both cases when they did these harder sessions they had a delayed recovery.
Compared to zone 1, where they recovered very quickly.
This leads to questioning how different zone 2 and 3 are, and whether we trigger a similar stress response.
- We have to keep in mind that the signal for adaptation and the stress that we impose on our body is not just a function of intensity, but it's intensity times duration.
Intensity in triathlon
- We've found that for HIIT training sessions, we tend to see very good results and a sustainable level of stress by being at the low end of zone 3, or in a 5-zone model in zone 4, instead of zone 5.
Meaning generally that athletes tend to choose to collect more minutes at 90% of heart rate max, and not go all the way into 95-96% of heart rate max, blood lactate at 10+.
- The adaptations seem to occur nicely by collecting 30-40 minutes at 90%, and the recovery comes faster, which is important.
- There is some drift that tends to happen in a workout too, do you may start at 88% but end up in the 90's.
- Athletes tend to spend time in the transition from zone 2-3, and usually just over on the 3 side.
They may collect 60 minutes here - but this would be a very tough session!
One of our professional rowers did this kind of session (6x10 minutes) 27 times in the year leading up to a gold medal. It was a standard zone 4 session for him.
- More typically, you'd do around 30-40 minutes at this intensity (e.g. 4x8 minutes).
Why does polarised training work?
- We tend to overestimate the importance of high intensity training, and think it causes distinct adaptations.
However the research does not support that. There is a lot of overlapping in the adaptive spectrum - for example, if you do enough minutes at low intensity it will improve your VO2max.
- We do have good data that shows when you get above the threshold you start to induce a stress response that you don't see at lower intensities.
This response is costly to recover from if it happens too often.
One of the best ways to overtrain an athlete is to train them 'middle hard' regularly. Having a monotone stress will make them stagnate at best, become overtrained at worse.
- If you want to keep the athlete healthy, and maintain their ability to mobilise a big high intensity response when they need to but also have good metabolic control at low intensities you need to distribute the work with a lot of low intensity, and periodic bouts of high intensity.
- Age group athletes unfortunately can commonly make this mistake.
Amateur athletes who don't have a lot of time to train will go out and do a 45-60 minute run right around threshold or above from the first minute.
It might not feel too bad! But you get stuck there, it's a training intensity black hole - you get sucked into the middle intensity.
The easy sessions get pushed more than they should be, so you're not fully recovered when you do a high intensity session and therefore they're not as hard as they should be and you fall towards the middle.
Distribution of training for time-limited amateurs
- The studies that we've done suggest this can be scaled down, and it still works.
- Age group athletes can really benefit from learning intensity discipline, and keeping low intensity sessions low, and then being able to mobilise when they need to do high quality sessions.
- Experimentally we've seen that the polarised model scales down to the 8-hour a week athlete, and even the 5-hour a week athlete.
- We can also think about how someone uses their hours.
If they have 6 hours a week and currently do one hour a day, you can think about doubling up and making one day a 2-hour session, and having a day off.
This will generate a better signal for adaptation - by stretching the low intensity session.
If you have to take a day free to do this, then that's what I'll do. I'll reassign time to get better low intensity sessions, as well as the good zone 3 sessions.
- Mikael's personal example: I've been focusing on my long rides, and getting rid of some of my intensity and extend the long rides. I've seen great results with doing 5-6 hour rides, which is much longer than half Ironman that I'm aiming for.
- My daughter is preparing for a half marathon and she's currently doing 2-hour long runs to build durability, and to be comfortable.
As we start to peak, we'll combine the long and the hard.
Getting comfortably uncomfortable with the reality of having to go hard when you're already tired.
- We have to think about stretching ourselves both in duration and intensity with different kinds of workouts, and then bringing it together in the competition.
Estimating the first lactate threshold
- Most people don't have access to fancy laboratory testing, they probably don't have access to blood lactate, but thy have heart rate, speed, power, and perception.
- If I'm working with an athlete and I don't have a lab, I want to know what their actual heart rate max is.
You'd be surprised how many athletes don't really know - it's not just 220 minus age!
It works reasonably well at the population level but it's unreliable at the individual level.
- Your heart rate max will likely be different for each discipline because they're movement specific.
Typically running will give the highest heart rate max, and we tend to call the others heart rate 'peak'.
The cycling heart rate peak might be 5-7 beats lower than the heart rate max in running.
Swimming will tend to be the lowest of the three.
- Usually the way you can identify this is through a hard 6-minute bout, even as part of an interval session - making sure you warm up well.
- This sets the top end of zone 3.
- If you want to find the first lactate turn point, you ideally need to measure lactate.
As a reasonable educated guess, keep it below 75% heart rate peak for zone 1.
- If you really are in zone 1, you should not see a big drift in the heart rate. The HR you have after 15 minutes should be the same as at 60 minutes.
If you're drifting up a lot there's a good chance you're working at a higher intensity than you think you are.
You start to see drift when you're closer to threshold.
- When you bring in people for testing who don't have good metabolic control and do a lot of work at threshold, they will be at 2.5mmol from the first stage of lactate testing.
They just don't have the low lactate starting point.
Whereas an elite endurance athlete will often be at below 1mmol, and may even go down from the first load to the second, before it eventually starts to increase.
- The good news is, when you take amateurs and get them to train in a disciplined way for a few weeks, it gets better!
The lactate profile starts to flatten out and look more like a well-trained athlete.
- Specifically for people who find their heart rate increases very quickly while running, there is no shame walking up a hill!
That was one of the first observations I made in Norway that started me on this - I watched a female athlete who I knew had a VO2max of 65mmol/kg, which is good, walk up a steep hill during a run session.
I learnt that she was doing a low intensity session and she was disciplined. She walked fast up the hill, kept her heart rate stable and kept going.
- We need to remember that training is training. Don't be afraid to be disciplined and walk when needed to follow your plan.
Elite athletes generally know what they're good for, they don't need to compete every day so they can remain disciplined.
Check the ego at the door!
- Women tend to be better at discipline, but men generally find it harder. However, learning discipline will be one of the best things you do.
- Slower can make you faster.
Estimating the second lactate threshold
- With cyclists I generally recommend doing an hour of power.
Do a 60 minute test and take your average power for those 60 minutes, and we'll call that your zone 2 threshold. This is the marker between zone 2 and 3.
- Research shows that well-trained subjects can hold maximum lactate steady state for an hour, so it's a reasonable surrogate measure.
- I often recommend doing the hour test, and then doing a 20-30 minute test, and work out what your calibration is.
You then don't need to do the 60 minute test often but you have it calibrated to your 20-30 test and you know your personal calibration.
- We can call that FTP and say it's your zone 2-3 demarcation.
- If you do an hour of power, your average rate rate for that hour will probably be around 90% of max.
- For me, when I do an hour of power, if I'm at 90% of heart rate max 20 minutes in, I can hang on.
By the end I'm at 95% of heart rate peak, but that's heart rate drift.
- The moment of truth comes around two thirds in - you know your body will start wanting to quit here so you need a mental strategy for how you can get past this.
- Using 20-minute tests to estimate FTP can often dramatically over-estimate it which has negative effects downstream.
You will tend to think you are at low intensity when you're at threshold intensity, which can be detrimental.
- Men tend to want bigger numbers, so they have a tendency to fall into this trap more.
- Cycling is such a power dominant sport these days but heart rate is still a really important tool in keeping to low intensity.
- For me personally, I tend to do my 100-120 minute low intensity sessions watching heart rate as well as power.
I can tell if I'm where I need to be from watching my heart rate.
- Keeping your easy rides at the same power and watching your heart rate come down as you adapt to the training can be really satisfying.
- Extending low intensity sessions can also be beneficial, and doing this slowly while keeping your heart rate flat builds durability.
This pays dividends down the road when you're racing.
- It's not always about doing more power, it's about being able to do the same power for longer, and feel comfortable with this.
This means you have a bigger aerobic base.
- If you were to look at the peloton of the pro tour, they tend to have a really high LT1 - this is what distinguishes these riders.
They very best have an exceptional ability to produce reasonably high power without it costing them anything.
- At the Tour of Flanders this weekend the winning time was 6hrs 18mins, in the last hour the cyclist had a lot of minutes at 400-500 watts, peaking at 900 watts.
So after 5 hours work the race begins - which requires an athlete with a fantastic base.
The only way to get this is to do the hours over time. There are no shortcuts.
Setting zones for running
- In theory it's essentially the same as cycling because the physiology is the physiology!
In practical terms, using a 10km may be a bit too fast as you're likely to be above maximum lactate steady state (MMLS) at the end, but it's close.
What you can do for an hour is a pretty good measure of your MMLS for running, but an hour run is tough.
- I would probably take 10km time and add some amount, but I'm not totally sure how much.
If you have a 10km and a half marathon, you can potentially use the time between them.
- The physiology is still related to the duration at the 60 minutes tends to work well as a surrogate measure.
I'd want at least 40 minutes, and up to 60 minutes as a functional test.
What's the speed and power you can hold in this range.
- For a well-trained athlete you could add 5 seconds per km of 10km pace, and for a less well-trained athlete maybe add 9-10 seconds.
Triathlon specific considerations
- Triathlon age groupers are often doing more than one session a day, which is great if you can manage it.
However, I would be more comfortable with an athlete doing two hard sessions on one day (e.g. hard bike and hard run), and then being able to have a really good low intensity or rest day after.
This is better than spreading hard sessions so you're doing something hard almost every day.
- Low intensity days may be high volume, but all at low intensity.
- It's important to remember that the best in the game are different beasts!
One of the things that makes them different is that they can absorb a lot of training.
What they can absorb is not necessarily for what the 7 hour a week athlete can handle.
- This is why the stacking your hard sessions together may be more sustainable.
- Taking the Olympic distance, the run is so critical and you need to be a strong runner for this distance.
For those doing this distance I would weigh more interval sessions on running.
- With other distances I think it depends on what your strengths and weaknesses are.
- I suspect a lot of swimmers can't actually swim at low intensity.
For that athlete, for swimming we may totally focus on getting comfortable in the water and let the technique carry you, not flailing with high intensity sessions.
I would focus on good swim mechanics, moving through the water well and breathing etc.
Example age-grouper training week
- 3 work outs per week in each discipline, 9-10 hours of training.
- As a starting point if we're going to follow the 80/20 rule, out of 9 sessions I wouldn't want more than 2-3 hard sessions.
For some this may even be too much, and there will be a tendency to try and solve all problems with intensity which is not a solution.
- I would be working with the athlete to keep them patient, and make sure the low intensity sessions are just that, making sure we have the heart rate on to calibrate these sessions.
- Then we're going to make sure our high intensity sessions are in the correct zone where they don't go into the highest intensity, but keep it around the 90%.
- Every week doesn't have to be the same - you can do 3 interval sessions one week and only 2 the next.
You could do 2 running sessions this week and next week do 2 bike sessions.
- The training process is hundreds of sessions in the course of a year.
Even an age grouper that's training 6 times a week, that's 300 sessions a year!
Each session is a tiny part of the picture.
- If the plan was to achieve 300 sessions with 75% of them being hard, were we able to achieve that?
Were they able to stay healthy enough that they achieved their goals, and this will be a measure of the overall success.
This is where you see long term progress.
- Stretch out your perspective when looking at your training.
- Cross country skiers that we work with are aware of their big picture - they know they need around 100 hard sessions out of their 500 a year to achieve their ideal fitness.
This helps you relax a bit if you get sick for 3 days!
- Unfortunately we have a tendency to think that every little detail is very critical, but I'm afraid to say I don't think the body is that sensitive.
Keep it simple.
- Some of the best athletes in the world (e.g. Kenyan runners) don't even own a heart rate monitor.
Evidence for high intensity loads
- Obviously I'm biased because I've been doing this a long time, but I really haven't seen any evidence of the benefits of a lot of high intensity work.
- I was speaking to a Norwegian coach once who had coached 12 different world champions in 4 different sports.
He said there is one certainty with endurance training - if you want to be great you have to train a lot and train smart.
- I haven't seen the short cut moments.
- I have seen athletes who have a long background of doing the volume, and they have a year where they try and cut their hours from 1000 to 800 and they can still have some success.
But they have the base, they know how their body works and they can get away with a season doing more high intensity less time.
What we tend to see though is that they are less consistent, and they have to start cherry picking when they will be good.
- Whereas a top class world cup athlete will generally say they had a great preparation period and they got the volume in.
- There will always be the exception, but I wouldn't want to base my coaching on that.
- There's a wonderful case study on a female Norwegian athlete who has won the most races as a cross country skier in the history of the sport on the women's side.
She won a world championship in 2005 and her coach was very in favour of a lot of high intensity training, so did some high intensity blocks.
She responded to it, she won a world championship.
However, then she was not able to keep making progress and she started to stagnate. She was considering quitting the sport in 2008/2009 as she was basically off the podium completely.
She ended up having to go back to basics and cut out the block high intensity work and return to the tradition model with lots of low intensity.
She then had a 5-year period where she was essentially unbeatable.
She achieved success with a high intensity loaded approach but it wasn't sustainable and she ended up stagnating. She only went back to a sustained period of success after returning to a more heavy low intensity model.
Rapid fire questions
- What is your favourite book, blog or resource related to triathlon or endurance sport?
- What is a personal habit that has helped you achieve success?
- When I get my head wrapped around something I don't let go easily. I'm passionate about this stuff too which helps.
- You need some endurance in your work process because it takes time to get good answers.
- What do you wish you had known or done differently at some point in your career?
- In endurance sports I did everything I'm telling the listeners not to do! I wish somebody had told me what I'm telling you now. I killed myself with interval training and I stagnated.
- Do a lot of easy training volume. Try to go and get a lactate test done, or listen back to how to set your zones, to make sure you are actually doing the easy training easy!
- Take a big picture view of your training, rather than a microcycle view.
It can feel like it's difficult to get faster when you're going slow for 80% of your sessions, but having a big picture view can help.
You're not going to improve in a week if you do some easy workouts, but when you stack them up and up for a year, or many years, that's when you see the changes.
- In terms of research, there isn't anything Stephen was aware of about the benefit of more intensity work. Anecdotally there are some examples, but it's usually a short term solution, not a long term success.
- This model fits in with what the best coaches in triathlon are doing.
Some of the best episodes we've had suggests this too, so it might be worth re-listening to these:
How Norway became a triathlon powerhouse with head coach Arild Tveiten | EP#154
World Champions keep things simple: training masterclass with Joel Filliol | EP#172
They may not call it polarised training, but the key thing is that what they are doing fit these concepts.
Links, resources and contact
Links and resources mentioned
- Training Priorities: Seiler's Hierarchy of Endurance Training Needs | EP#120
- How Norway became a triathlon powerhouse with head coach Arild Tveiten | EP#154
- World Champions keep things simple: training masterclass with Joel Filliol | EP#172
- The Training Characteristics of the World's Most Successful Female Cross-Country Skier
- Seiler's Hierarchy of Endurance Training Needs.
- Does Polarized Training Improve Performance in Recreational Runners?
- Quantifying training intensity distribution in elite endurance athletes: is there evidence for an “optimal” distribution?
- Autonomic Recovery after Exercise in Trained Athletes: Intensity and Duration Effects
- What is Best Practice for Training Intensity and Duration Distribution in Endurance Athletes?
- Intervals, Thresholds, and Long Slow Distance: the Role of Intensity and Duration in Endurance Training
Connect with Stephen Seiler
Connect with host Mikael Eriksson
Hi! I'm your host Mikael,
I am a full-time triathlon coach and an ambitious age-group triathlete. My goal is podium at the Finnish national championships within the next few years.
I first started the website Scientific Triathlon in autumn 2015 as a passion project to share my learnings with a larger triathlon audience. Later on, in early 2017 I started the podcast That Triathlon Show.
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