Podcast, Science and Physiology

Polarized versus Moderate intensity training: a controlled trial in triathletes with Dr. Golo Röhrken | EP#278

 March 22, 2021

By  Mikael Eriksson


Golo Röhrken is a medical doctor, sports scientist, and triathlon coach. In this interview we discuss a study he conducted, which was the first ever randomised controlled trial comparing polarised training with other training intensity distributions specifically in the sport of triathlon.

In this Episode you'll learn about:

  • The first ever randomised controlled trial of polarised training and moderate intensity training distributions in triathletes
  • How the two training programs were implemented and executed
  • Different ways of quantifying training intensity distributions, and problems or misunderstandings that these differences lead to
  • Golo's coaching advice and practical takehome messages from this study and beyond

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05:25 -

  • My name is Golo Roken and I am a medical doctor as well as having a master in exercise physiology.

    Moreover, I am also a triathlon coach and an avid triathlete myself.

Polarized versus moderate intensity training study in triathletes

06:30 -

  • Quite recently I published a study that investigated the training response among triathletes from a polarized training approach compared to a training distribution where plenty of the training is conducted in the moderate intensity zone.

    The effect of a polarized training approach compared to strongly emphasizing moderate intensity work has been well studied in many other endurance sports but to our knowledge, no study has solely focused on triathletes.
  • First, however, I would like to define polarized training and exactly what we mean with the training zones.

    Polarized training means that the vast majority of the training is conducted in the low intensity training zone and that the remaining part of the training is performed in the high intensity zone (almost no training is done at a medium intensity).

    By low intensity training, we mean a training intensity below the ”first” lactate threshold (where one recognizes an increase in serum lactate during a ramped lactate threshold test).

    High intensity training is training conducted above the ”second” lactate threshold (the anaerobic threshold) and medium intensity training is defined as all training between these two zones.
  • It’s also important to define how the ratio between low, medium and high intensity training is determined.

    There is basically two approaches for this, the first one labels one single session as either high, moderate or low intensity depending on the intent of the session and the second approach is based on the actual ratio of time spent in each training zone.
  • Our study spanned over six weeks and were conducted on fairly well-trained triathletes.

    The medium intensity group spent around 30 % of their total training time in the medium intensity zone and the rest of the time in the low intensity zone (based on HR).

    The polarized training group had one high intensity session every week in each discipline.
  • In our study we could not see any significant difference between the medium intensity group and the polarized training group.

Limitations of the study

23:40 -

  • There was a quite big drop out in the polarized training group and the actual distribution between the training zones were rather far from the pre study intent.

    The medium intensity group could to a much larger extend keep the intended training distribution and fewer subjects dropped out.

    This raises the question that the polarized training approach could be too taxing for many athletes to cope with (many of the subjects in this group failed to reach the HR target by the end of the study indicating this).

    However, a polarized training approach could be very effective, but it seems like it is very taxing to the body and maybe one can do some minor alterations to make it slightly more manageable (like reducing the intensity of the intervals a little bit).

Real world applications

34:30 -

  • After the study, I have actually become more and more reserved with my prescription of high intensity training since it seems to be so easy to push the athletes ”over the edge” if they get too much of it.
  • The importance of having a very high central VO2max (which is what you are mainly training with high intensity intervals) might not also be of similar importance for triathlon compared to sports like rowing and cross country skiing.

    I have seen many amateur athletes having insanely high VO2maxes (70-75) and they are desperately trying everything to get it towards 80, while they simultaneously exhibit a quite poor metabolic efficiency (a high VlaMax), making them extremely dependent on carbohydrates as work fuel, which simply isn’t feasible for an Ironman.
  • I found rather race specific intervals to be very effective (20-30mins long tempo/sweetspot intervals preferably as low cadence) performed in the aero position.

Top advice to listeners

44:40 -

  • I would like to say that staying healthy and managing fatigue is the first thing.

    From this baseline one can start thinking about the next basic principle for success: continuity.

    After that my best advice would be to train specifically for your targeted event.

Rapid fire questions

45:50 -

  • What is your favorite book, blog or resource related to endurance sports? From a scientific perspective I really like what Inigo San Millan has published and from a coaching perspective I like much of what Dan Lorang is saying.
  • What is your favorite piece of gear or equipment? The HR monitor.
  • What is a personal habit that has helped you achieve success? Getting up early in the morning where I do something for myself that I like.

Short personal comment on the subject from Mikael

49:00 -

  • I would like to state that I am of the firm opinion that training intensity distribution is something that should only be used for descriptive purposes and not for prescribing purposes.

    There are so many factors impacting the final training intensity distribution, such as overall training volume and what primary event the athlete is targeting.
  • I think that many athletes are paying too much attention to small details like what exact percentage they are spending in each training zone instead of looking at the broader picture.

    One of my greatest advice is to look at the demands of the race that you’re targeting and plan your training to prepare in the best possible way for that!


Mikael Eriksson

I am a full-time triathlon coach, founder of Scientific Triathlon, and host of the top-rated podcast That Triathlon Show. I am from Finland but live in Lisbon, Portugal.

Please contact me if you have feedback on the podcast or want to make suggestions for improvement or send in a question for a Q&A episode.

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