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Thanks Joe. This is a fascinating topic with potential wide ranging implications for training.

While the results are clear cut I find the protocol for the HIIT and THR sessions a little confusing. The majority of the participants would, I guess, be using HR as their measure for intensity (since most were not cyclists)

The study says HIIT sessions were 4x4mins@90-95% of HRpeak with 3 mins active recovery in between.

Isn't this a little "low" for HIIT? I would have thought to be real "High" intensity target would be 95%+ or, perhaps preferably, expressed as lactate threshold HR+.

The study does not specify how those conducting THR sessions controlled intensity. It does though say that subjects in this category included 2x20 minute intervals.

What I find weird for this group is that Table 1 of the results show the THR group spent 0% of time at HIIT. If this means over the course of 9 weeks their HR never went above 90% to me this is very strange, even the HVT group recorded 1 hour in this zone.

So I am left asking myself if the THR group actually did threshold training as I would understand it? For me target power for this would be FTP+/- 5% or so. Doing these I would expect HR towards the end of intervals to be 90%+.

The results of the "THR" group look more as if they were training at lowish sweetspot level which makes the relatively poor results on a ramp test more understandable.

This is not to decry the results. They remain very interesting. However, as a cyclist, I would be more interested in a similar study but with only bike riders using power meters to more precisely control intensity and discriminate between groups.

Given how commonplace power meters are now I would have thought this would be a relatively easy process. Perhaps you could even run one yourself, I'd imagine you have a ready cohort of volunteers amongst those who read your blog.

Tommy Johnson

As I was reading the description of the POL Group and the Results, the question that came to my mind was "How is the race intensity determined using POL type training?" Take Ironman for example. The athlete will neither race at HVT nor HIIT intensity. But then in the Conclusions you discussed "specific preparation". I have my athletes spend a significant amount of time on race specific training at the intensity at which they will race. The POL type training could be used earlier in their training.

Luke Majewski

Good review of the latest research, Joe.

I've been following a pretty strict polarized model for CX season. I do Z2 all week and my HIIT is my openers and my races. I'm pretty pleased with the results. However, I'm on such low volume that I am sure I could take on more TSS. That being said, some of the other studies looked at low volume and still found POL to be advantageous. When I say low volume I mean about 4-5 hours of Z2 (1 hour a day) on a trainer and openers and racing outside (maybe another 1.5 hours). Any new take aways for people in my time crunched situation?

Joe Friel

Luke Majewski - Good point. I believe that the less time the athlete has to train in a week, the more emphasis should be placed on >AnT intensity.

Joe Friel

plus.google.com/111510469615380609520 (Don't know why the site assigned this "handle" to you--sorry about that). Yes, heart rate was used by all of the athletes, including the cyclists, to gauge intensity.


Typepad assigned this to me.

Yes I missed the fact that HR was used in my first read through. I must say that in light of this I find the headline of this study misleading.

To my mind this study has nothing to say about "threshold" training since no-one actually trained at threshold level.

The so-called threshold group actually did short sweetspot intervals. The HIIT group were actually closer to threshold than the THR group.

What I think this study showed again was;
- HR is a poor indicator of intensity. While it has to be used for some sports there is simply no excuse for using it rather than power for cyclists. The cyclists in this study should have had separate measure of power. The fact that they didn't makes me question the quality of the investigation. Apart from the calibration of zones power would also have allowed some objective comparison between groups in terms of TSS/TSB. Done correctly this would yield interesting extra information.
- The first rule of training is specificity. The "Threshold" group actually spent 9 solid weeks doing efforts at sub-threshold levels, with their HR never going above 90% of max. It's not a surprise then that when they do a test measuring effort at threshold/VO2 they have not improved. They were actually de-training wrt to this intensity level.



I'm a little confused as to how to designate the percentage of training done at low vs high intensity. If I do a 60 minute trainer workout with a 20 min warm up, then 5 x (2 min @ V02max x 2 min RI) and finish with a 20 min cool down would you consider this to be 50 min at low intensity and 10 min at high with regards to polarized training. On a 3 hour weekend ride if I did 2 1/2 hours at low intensity and 30 min of hill climbing at V02max (in multiple segments, of course) is this 150 min low and 30 min high intensity?
How realistic do you think this type of training is? One thing you emphasize is to make your training more race like as you get close to your "A" race. I spend a large amount of my race time at a tempo HR. I would think to make my training race like I would spend a lot of time at tempo. Comments?

Thanks, George

Joe Friel

geocof2249-- I would calculate high-low just as you suggested in your explanation. I can't tell you how much, but I'd suggest increasing your tempo time as a % of training as you get closer to your A race (and, of course, allowing for R&R).

Luis Ig Caballero

Dear Joe,
A month ago I had my VO2max estimated in a lab test after starting with your fantastic "total heart rate training" book. I am enjoying it so much. Although I am just an amateur I enjoy learning about how body reacts and improves since being a diabetic type 1 I have to take care of myself anyway :). Now I have reached the ATP (annual training program) phase described in your book. When I did the effort test the doctor told me about a newer way of training with very interesting achivements (Polarized training). Do you know of amateurs sporters that tried the polarized training while increasing training volume from scratch? I'm already happy being able to train 6.5h a week with family and 40h job, however I wonder if that volume training will be enough to finish A-races like Olimpic triathlon or whole marathon by May and Oct 2015. I agree with you that there is not "one" way of training, but when it starts making sense to include polarized training in the Base 2 & 3 as well as in Build 1 & 2 phases when still in the "beginners" phase of the sport(s) year(s)?. The other question would be when certain goals start to become unrealistic for a given training volume (maybe in that case polarized training sold as holly grail of time vs performance improvement starts making sense or it will just lead to injuries).

Thanks a lot in advance!

With best regards,


Joe Friel

Luis Ig Caballero--Yes, I've had amateur athletes tell me they train with a polarized approach. Good luck!

Elizabeth Weidling


Would it be effective to approach this with doing your low intensity efforts on the run and keeping the high intensity efforts on the bike and swim (specifically if you have an athlete who needs to develop their aerobic base)? Thank you - Liz

Joe Friel

Elizabeth Weidling--It really comes down to which sports do you need to improve high-intensity (e.g., VO2max) fitness the most. (BTW, it's "Joe")

Mack H. Williams IV

Coach Friel,
Excellent topic to open a coach's eye to an advance approach to training. Based on your topic the focus for setting base should remain in base 1, and 2 while dabbling in Build 3. However, high intensity should remain in Build 1 and post Build 1.
What percentage of mileage would you consider for AeT vs Vo2 intervals in both cycling and running during Build 1 and 2? Should this percentage be based on days trained, volume, or mileage...
Thanks again, Mack

Joe Friel

Mack H. Williams IV - I don't think there's a one-size-fits-all intensity distribution as there are so many variables such as race distance, physiological limiters and seasonal variations. The ratio is going to grow out of the consideration of these things and will be quite individualized. Some trial and error will be necessary to figure this out also. And even after all of this is parsed out for the individual athlete the ratio will still just be a rather big ballpark as things change in people's lives on a fairly regular basis affecting how much high-intensity training they can tolerate. This is what makes the wise coach so valuable.

Dorian Jawoszek


I like the concept of POL, however I'm bit sceptical when it comes to comparing with LTH group and overall design of this a study.

First of all there is no information WHEN the study was taken place, and where were athlete with their training when coming into study, which is a major factor here. Keeping aside the training history of participants, it looks like the study was taken in early spring(late build) after base/build periods. So, let's say' after they completed they base/early build blocks - assuming that they follow general periodization paradigm- they turn into this study training, which for LTH group looks pretty much the same as the work they've done in previous weeks. That would break the periodization rule, which would results in performance plateau for LTH group.

It, just doesn't seem legit that LHT didn't improve at all over 9 weeks when the training is aplied correctly. Sure they are highly trained but V02max at 62ml/kg isn't sky high either. I'm curious how results would look like if participants were detrained before this program.

I'm not advocating that LTH is worse or better than others, but it's a single study and the design could be better. and I would love to see more of this kind research.

BTW, There is another Seiler's study on recreational cyclists, and Sandbakk's study on highly trained(VO2max 67.4 +- 7 ml/kg) XC skiers, and both conclude that longer intervals(5-10min) at and above AnT lead to greater improvements in endurance performance and oxygen uptake when comparing to shorter intervals(<5min) group. That's very interesting, a bit contradictory with what have here.

Thank You Joe, for this exciting information.

I have a question: I You were up to prescribing POL training plan, how would You periodize it over the Year??



Joe Friel

Dorian Jawoszek--Good comments and insights. Enjoyed reading your thoughts. I, too, look forward to more such studies. As for your question about POL relative to periodization, please see my comments near the end above. It comes down to what type of event are we talking about.

Frederic Carrier

I'm not clear about what the POL subjects did on their 3rd week?
Often as a triathlete, I train twice in same day: same sport twice or 2 different sports.
Quote " Every third week (recovery week) they alternated days off with a single HIIT session and long workouts done below AeT."

Did they do
i) Monday off; Tue: 1 HIIT and 1AeT Wed: off Thu: 1 HIIT + 1 AeT Fri: off Sat: 1 HIIT + AeT Sun: off

ii) Mon: off Tue: 1 HIIT Wed: off Thu: 1 AeT Fri: off Sat: 1 HIIT Sun: off

Joe Friel

Frederic Carrier--They did: MON-day off, TUE-HIIT, WED-day off, THU-long, etc

Pete Garrod

Hi Joe,

I have been incorporating the high intensity work within longer training sessions and trying to maintain an 80%/5%/15% polarization on an aggregate basis. Subsequent sessions do therefore vary in intensity based upon the intention to maintain those percentages...

Is this a wise approach? I note that it is a different regimen to that in the study and to what you advocate above but does it make a difference?

What troubles me is that if an hour of HIIT was 10% of a weekly load, but say only half of that time is spent >AnT, it still seems to count as an hour towards AnT - or have I misunderstood?

Joe Friel

Pete Garrod--I'm still learning about polarized training. I don't have any firm answers as I believe the ratios must vary based on the event you are training for (crit? IM? etc) and the time in the season. The only thing I can say with a degree of certainty is that a huge chunk of time should occur at AnT even if heart rate or power or pace didn't actually achieve those levels. This could happen, for example, with very short intervals when using a heart rate monitor. Hope that all makes sense. But if not let me know.I'd be interested in your experiences from training this way. Thanks!

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