Myths, Legends and Polarised Training

You may have heard of polarised training. In fact if you’re a competitive cyclist you almost certainly have and it’s held up by many as the holy grail of endurance training, which will result in you almost certainly result in you being recruited into the pro ranks even if you’re fifty two years old, slightly overweight and only ride your bike for 5 hours a week.

All you need to do is make sure than 80% of those 5 hours is really, really slow and easy and in the other 20% you chuck in a few 30s sprints and bingo you’ve cracked it. You’ll also be aware that at no time at all must you ever dream of doing any kind of extended effort at sweet spot, that hard intensity just below your functional threshold power. This as everyone who has studied the reports on polarised training knows is evil and like kryptonite to superman. If you stick any of this into your five hours a week you can kiss your pro contract goodbye. Or can you?

If you’re really bored and have a bit of time on your hands I would recommend you have a good read of the research paper below. While writing this article I did a fair bit of googling and this paper came up again and again as an example of why polarised training is amazing.  

Stöggl T and Sperlich B (2014) Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training. Front. Physiol5:33. doi: 10.3389/fphys.2014.00033

I’ll summarise it for you. 48 well trained (I don’t think they were that well trained and there is no mention of what level of fitness they were at before the programme began) endurance athletes who were a combination of runners, cyclists, triathletes and cross country skiers all did a 9 week training programme which consisted of 3 x 3 week blocks. Each block consisted of 2 build weeks and an easier week. They had they’re V02 max test before and after the programme which for the cyclists was by a ramp test on indoor trainer

Of these 48 well trained (but sickly) athletes only 41 finished the survey as 7 dropped out due to illness, boredom and in one case insanity. I made that bit up. I can’t say for sure if insanity played a part in the test. It’s sure played a part people’s thinking since though.

I don’t know how many of the remaining 41 were pure cyclists but assuming it was an even mix I’d guess about 10 or 11.

They were then split across four groups. One group did a high volume of training exclusively at below lactate threshold 1 (zone 1).

Bit of an aside here. Don’t think of lactate threshold as like riding at bang on the ragged edge in a 25 mile TT. Lactate threshold one is the point where lactate levels get to about 2mmol / litre which by and large happens at about 75% of max HR – not very intense at all. Kind of at the bottom of your tempo training intensity. So if you were riding at about 75-85% of your FTP and you were in decent nick you’d be around your first lactate threshold.

The second lactate threshold occurs when blood lactate levels get to about 3.5 / 5 mmol / litre. This is happening at somewhere between 80-90% of max HR. You’re just about getting to sweet spot intensity here, maybe 20-40 watts below riding bang on the raged end of functional threshold power / the best effort you can hold for an hour. This is actually well above your lactate threshold 2.

Disciples of the polarised training model believe all riding between lactate threshold 1 and 2 is evil and must be avoided at all costs. They also believe the earth is flat and electricity is the work of witches. This evil zone of death between the lactate thresholds is classed as zone 2 in polarised training. Work above this zone is classed as very intense and is known as zone 3. No surprises there.

So basically this group just plodded about at really low intensities.

Another group did very low volume and nothing but intervals above lactate threshold 2 in zone 3. Don’t confuse this with balls out interval training – just efforts at or below FTP (assuming they were long enough) would be enough to exceed lactate threshold two.

Not surprisingly both these groups did pretty badly over the course of 9 weeks. The poor fools.

Then we had a group who were allocated to threshold training. That is their key sessions took place between the lactate thresholds – zone 2. Some work was done below this in zone 1 and nothing in zone 3.

Each build week of the 9 week block consisted of

  1. 2 sessions of an hour each with 5 x 6 min around lactate threshold 2 (so probably around top of tempo, maybe 30 watts below FTP.
  2. A 90 min ride with 3 x 15 min tempo efforts – maybe 40-50 watts below FTP
  3. A 75 min fartlek ride with random efforts in zone 2 – no mention of duration and frequency of these efforts
  4. 2 x 90 min rides in zone 1 – so very easy

In each block there was some small progression of the time spent in zone 2 but not much. What strikes me here is that overall the load here is pretty low. Less than 500 TSS (Training stress score) points I would say and there is no intensity at all. 6 min up near the top of lactate threshold – so just on the verge of sweet spot is not going to ask many questions. Remember we’ve probably only got 2 or 3 cyclists in each group too.

The easy weeks consisted of 1 x 60 min zone 1 ride and 2 x 1 hour rides with some work at lactate threshold – doesn’t state what that involved but can’t imagine it was any more intense than the work in the build blocks.

Now we had a polarised group. They did their key sessions in zone 3, nothing in zone 2 and the rest at an easy zone 1. Each build week for them consisted of the following

  1. 2 sessions of an hour each comprising high intensity efforts in zone 3 – doesn’t state what these effort were.
  2. 2 rides of 2 to 4 hours in zone 1 but with a number of 5s all out sprints
  3. 2 rides of 90 min in zone 1

I would guesstimate that this would generate a TSS of 500-600 points a week AND on top of that there was some intensity. If I wanted to make any progress I’d choose this group.

The easy weeks had 1 ride of 2 to 3 hours in zone 1, a 1 hour high intensity session and 90 min in zone 1. So again more load than the polarised group.

At the end of the 9 weeks both the threshold group and the polarised group had made progress in V02 max in the ramp test but the polarised group had done considerably better. Therefore polarised training is the best – hoorah!

Well no. This is what it actually tells me.

  1. Not enough cyclists in the study to give a definitive trend
  2. None of them can have been all that well trained to start with a relatively modest training load like this created such a big jump in V02 max
  3. The polarised group did more overall work and more intensity than the threshold group. This was why they made more progress not because they were working in a polarised way. E.g. If I do 2 x 1 hour sweet spot sessions a week and a 60 min steady ride and my mate does 3 x 3 hour steady ride and a session with some balls out intervals after a few weeks he is going to have made much more progress than me because overall he is stressing his aerobic system more by doing a lot more work.  End of.
  4. The whole paper and study simply proves that one inefficient poor training plan is better than another inefficient, poor training plan because it has more total work and some intense work in it. It DOES NOT make a case for polarised training.

I always thought that the mortal enemy of polarised training was the threshold model which involved a lot of strong riding either just below functional threshold power, at functional threshold power or just over. The more I’ve read it seems to be that work around FTP would actually fall into zone 3. In other words what you would class as very hard training in the polarised model.

So actually polarised training’s real mortal enemy is a training model which gravitates to doing pretty much but doing nothing but riding at tempo intensities. I.e. no intervals, no steady riding just endless mindless middle of the road neither hard nor easy plodding along. There is certainly a time to do rides like this but not ALL the time.

So yes. You won’t get very far if that’s all you do. But not that many people actually do train like that. So this silly middle of the road training model which hides under its misleading title of threshold training is what is continually put up as cannon fodder against the polarised training model in the various studies that are out there.

I found another report here

This one had only cyclists and had a controlled detraining period for all of them before the training began. So far so good. Their V02 max and other various parameters were tested before and after a 6 week training plan which pitched the mighty polarised training model where all riding in zone 2 is verboten against the hated ‘’threshold model” were riding in the degenerate zone 2 was positively encouraged. I was initially excited but that soon waned.

Essentially the groups were split into 2 groups of 6 and each rider in the group visited the lab 3 times a week for 6 weeks.

The polarised group came in on a Monday and a did a session on a computrainer which included 6 x 4 min in zone 3 with 2 min recoveries, again on a Wednesday and on a Friday a 1 hour bimble in zone 1.

The threshold group came in on the same days but instead of the 6 x 4s did an hour continuous in the middle of Z2 – so tempo basically and a one hour bimble.

Now if you ask me what would yield the best results over a 6 week period – 2 x 6 x 4 min over threshold and a 1 hour bimble or 2 steady tempo hour and a 1 hour bimble I would say the former because overall it generates a slightly greater training stress and it has some intensity. It is not comparing two models of training. It’s simply saying that in the short term doing some hard intervals are more likely to make your numbers go up than doing a steady tempo hour. No shit Sherlock!

But the real kicker which makes the whole test invalid was that away from the lab each rider did 2 to 3. Not 2 OR 3 zone 1 rides and the duration was not specified. So in theory we could have one rider who did 3 x 3 hour zone 1 rides which would generate a very big training stress score and another who just did 2 x 1 hour bimbles.

You can’t possibly have a meaningful study with such huge variables in it.

Yes the polarised group won this meaningless contest but what actual logical conclusions you can draw from that I know not what.

What would make for a really good scientific research paper would be to get 12 riders of similar ability, split them into 2 groups of 6 and limit them to a max training time of 8 hours a week. I.e. about the same as the normal working person with a young family. Limit one group to only being able to train in zones 1 and 3 and the other to train it whatever damned zones they like! Then see who does best at the end of that.

Ultimately in the end quantity will always triumph over quality. Just look at Weatherspoons! If there were two identical riders and both were allowed to train for 7 hours a week maximum and with one rider you were allowed to train in zone 2 and with the other only in zones 1 and 3 I guarantee the rider who was allowed to train in zone would do better. That’s assuming he / she knew what they were doing.

However if one of those riders was allowed to train for 14 hours a week, even if most of those hours were in zone 1 the overall aerobic training load would be higher and assuming they didn’t get run down and ill all things being equal they would do better.

Pro cyclists do huge volumes of riding and by necessity if you’re going to 20 plus hours a week of riding it needs to be at a pretty low intensity. If you try and do 20 hours of work in zone 2 you’re going to end up destroyed.

It doesn’t follow however that looking at the ratio of time a pro cyclist spends in zones 1 and 2 and 3 will scale down for an amateur with a lot less time to train.

Ultimately it comes down to the basic principles of progressive overload. Riding in power zone 1 for an hour does not create the same level of aerobic training stimulus as training up near the top of zone 2 for an hour would. I would need to do at least twice as much time in zone 1 to achieve that.

Without a doubt there is a saturation point for gains that can be achieved by riding in zone 2. As an example back in 2012 I got myself a coach. Near the start of the racing season I picked up a really bad bug which knocked me for six and I was ill for many weeks and physically and mentally terrible.  I felt a coach would really help me get my mojo back. Indeed they did. Between the end of April and the middle of June I was doing maybe 7 or 8 hours or riding a week and most of it was in zone 2. July and August saw me in great form and I got my PB 10 mile TT time of a 19.04 in that period. I was flying.

During the offseason I kept the coach and I have never trained as hard. I was often doing 12 hours a week and by March I had a CTL score in the 100s far beyond anything I’d ever done before. This was mostly made up of hard riding in zone 2. I have to say though I felt terrible. Hard riding day in day 2 close to your aerobic threshold is incredibly draining. I don’t know how I did it but I’m glad I did because I learned a valuable lesson. It doesn’t work.

I had a very average season. My numbers weren’t terrible but they were very slightly down on what I’d done the season before. I now know that had I done less zone 2 work and more zone 1 work even though my ctl would have been lower my actual power numbers would be much better.

Like everything there the key word is OPTIMUM. Depending on who you are and how much time you have to train there is an optimum amount of time you can spend each week in ALL the zones.

(As a postscript I sacked his sorry ass half way into the season and turned a terrible season into an ok / mediocre season with a few weeks of polarised training. In this instance a body that was exhausted from too much work in zone 2 did respond well to a diet of very easy riding and a few intervals. If I’d trained properly though from the outset with a good balance of training across all 3 zones it would never have come to that.)

Great things happen in zone 1, great things happen in zone 2 and great things happen in zone 5.

If I was coaching a pro rider who had huge amounts of time to train and recover I would very probably gravitate towards a polarised approach. If you have a lot of time there is no doubt that it does work. We’re talking about ever diminishing returns however. A pro training 20 hours a week using a polarised model compared to the same rider doing 10 hours a week who utilised all 3 zones would be better but not by very much. But I guess if you’re livelihood depends on it the extra hours are worth it.

Anyone who trained less than 10 hours a week I would not bother with a polarised approach unless it was peak season between races. You just cannot adequately build a powerful aerobic engine without being able to utilise the amazing things that happen in such a time efficient way in zone 2 AND zone 3.

That’s important to note too. Many really good sessions straddle two zone and can’t be classed as one of thing or the other. As an example imagine I ask a rider which doesn’t have great muscular endurance to do 2 x 20 min sweet spot efforts at 90-100% of their functional threshold power.

Effort one might not feel too bad and the in terms of blood lactate it may all be in zone 2. Effort 2 might start to get grippy half way in and in the last 10 min blood lactate levels are up in zone 3. Would we want to abort the session as soon as that happened? Of course not. The message we are giving the body then is – yeah its fine to stay as you are, don’t bother adapting because as soon as it gets grippy we’ll back off!

With riders I coach when I’m trying to build the engine and by that I mean the basics of aerobic fitness;

  1. Increased mitochondrial volume
  2. Increased capillarisation
  3. Increased mitochondrial power
  4. Increased pumping capacity of the heart
  5. Increased muscular endurance

I use training in zones 1, 2 and 3. I see no reason to neglect any of them. What doesn’t seem important is the ratio of time spent in all zones and it should be like a pyramid. The Unless you really are super time strapped the real bedrock of your weekly plan through the winter months should be a long ride that straddles zones 1 and 2 at about 60-80% of your FTP. This is best done when you’re carrying a fair bit of fatigue from the other sessions of the week. This ride is the base of your pyramid which supports everything else. Aim for 30-40% of your training time to be done here.

Then spend about 30% of your time slap bang in the middle of zone 2 – tempo riding at 75-95% of FTP. Maybe 20% of your time should be straddling that threshold between zones 2 and 3 – strong, sustained riding just below to just at FTP. Only about 10-15% of your riding should be in zone 3, certainly no more than that.

This of course varies on a case by case basis. I need to consider such factors as how much the rider has to train, the age of the rider, the depth of the fitness the rider has and a thousand other factors.

But I won’t be asking any rider I coach to spend the entire winter creeping about at speeds so low frostbite becomes a danger interspersed with coronary inducing sprints any time soon.

John Morgan