Seiler’s 8-minute intervals (Polarized)

Lols, I struggled with Mount Hope-2 a few days ago which is 4x10mins at 95-99% FTP and 6min recoveries! I was a little fatigued from the weekend of training, but still…I did however really enjoy the workout.

I previously did sustained power build and I am DONE with anything 80-100% FTP. How I even thought that would be of benefit I do not know (I have a Masters Degree in Sport Science). Sweet spot is nothing more than a no-mans-zone intensity that’s too low to create adaptation but high enough to create fatigue.

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Sweet spot and threshold have worked for me. So have VO2max and sprint work. Not everyone responds the same.

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Didn’t think the sustained power had that much sweetspot work. Thought it was more threshold, U/O’s and VO2. My experience with sweetspot (90% ftp) is that it’s hard enough to bring about adaptations but not so hard that you can’t do back to back days. Think it works well for building a base early on in the season. Horses for courses and all that!

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Sounds like the Polarised training thread is where you need to be

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The intensity factor is 1.03 but the workout length is only 38 minutes. I don’t understand why you think that a rider shouldn’t be able to complete that.


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Well, yes, but the subjects were asked to do even pacing across all four of the intervals, so it makes sense that the intervals should all be at the same power. The trick is to decide what power that need to be at to get to the end only just able to complete the last interval. This is were it becomes very individualised.



Maybe you’re right. I think I was mixing up the numbers I put in for 105 and 108.

Though by the time you get past 30 minutes, the power curve is pretty flat. 38 minutes at 103% is a seriously tall order. TT race pace territory.

These intervals are very hard.

It will depend on the specific rider too. My numbers are a percentage of my FTP taken from a ramp test, which I’m pretty sure overestimates my LT2 so the actual percentages could be a little higher.

I’ll be interested to see what happens after my next FTP test.


I just think of those 2x8min tests and trying to hold very close to that with minimal recovery… ouch ouch ouch ouch

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The 8 minute FTP test assumes that your max 8 minute power is ~110% of your FTP, so it would be really surprising if someone could do 4x8 minute at only ~2% below that “max 8 minute” effort, that would be some seriously impressive repeatability.


I think that’s a fair observation, and as it is, I haven’t worked up to the full 4 x 8 minutes yet, and it’s been a while since my last test…

To complete the picture around the different FTP tests:

The 8 minute test is 2 x 8 minutes at 111.1% FTP (100/90) with 10 minutes of rest between. The IF for this is 0.99 for 26 minutes.

The 20 minute test is 1 x 20 minutes at 105.3% FTP (100/95) with a 110% 5 minute effort before that to reduce the anaerobic contribution. The IF for this is 1.01 for 30 minutes.

On reflection I could see the intensity being reduced back a little to get to the full 4 x 8 minutes.


Although many people believe that 95% of 20 minute test overestimates most people’s FTP. Which would - if the ramp test is a better test for FTP - tilt things back towards 1.03 intensity for 38 minutes being just about possible.

Just adding my 2 cents. I was going to try a polarised plan this year but have since changed my mind. However I did try a scaled down version of the 8min intervals, 3 x 8, using Seilers method of let the athlete figure it out. I’m no athlete but I soon figured out I went too hard on the first interval when the 2nd kicked in!

1st was just a smidge under 110% ftp. 2nd was 106% and third 105%. Had I not gone as hard on the 1st interval, I’m fairly sure I could have ridden all three at 107% or just under.

One thing to note, the 2 min recovery intervals are not set in stone. Seiler said that he found most athletes only needed 2 mins before going again. If I were to do these again, I would increase them from 2 mins to 3.

Try Raymond +7 first and see how it goes.

I modified that workout and reduced the intervals to 2 minutes and completed it. Not sure I was hitting the 108% though with my naff trainer.

Yes, that’s correct. If I remember correctly there was a study into self selected rest periods and the result was that 2 minutes was perceived to be enough. Seiler has said himself that it isn’t crucial.

Maybe like with most of this it’s very easy for people to latch onto the result of a study and decide that it means something it was never intended to show.



Then why assume extended rest would be critical to total time in zone?

You have taken my quote out of context. That was specifically referring to the number of rest periods not the length of them.

However, I was thinking about how extended rest periods could change the amount of time in zone. By starting at a lower heart rate after 3 minutes rest compared to 2 minutes rest you would have to work for longer to get to the desired zone.


Forgot it was 2x8, thanks for the clarification. So it’s actually 4x8 at 3% lower than 2x8 power, tough but might be doable!

It’s all dependant on fitness. Seiler was looking at highly trained athletes. For them, 2 mins was probably enough time for their heart rate to drop low enough for them to want to go again. For me, I needed longer. I’m sure he has said that it doesn’t matter if your rest interval is longer.