Podcast, Training

Arild Tveiten – coach of Kristian Blummenfelt, Gustav Iden and Casper Stornes on triathlon training the Norwegian way | EP#223

 March 2, 2020

By  Mikael Eriksson

Arild Tveiten - coach of Kristian Blummenfelt, Gustav Iden and Casper Stornes on triathlon training the Norwegian way | EP#223

Arild Tveiten is the coach behind Norwegian triathlon successes such as Kristian Blummenfelt winning the WTS Grand Final 2019, Gustav Iden winning the 70.3 World Championships, and Casper Stornes, Kristian and Gustav sweeping the podium in the WTS Bermuda race in 2018. He returns to That Triathlon Show to discuss his training and coaching methodologies, and how Norway are working towards Olympic medals in Tokyo 2020.

Discuss this episode!

  • Let's discuss this episode and the topic in general. Post any comments or questions in the comments at the bottom of the shownotes. Join the discussion here!

In this Episode you'll learn about:

  • The testing methods used by the Norwegian team to be able to strictly adhere to specified intensities.
  • The training methodology they use, with the main pillars of high volume at low intensity and a substantial amount of work at lactate threshold (LT2).
  • What they've changed in the 1.5 years since our previous interview, including more intensity in swim training.
  • How they are preparing to medal at the 2020 Olympics in Tokyo, including periodisation, training camps, and heat acclimatisation.
  • The differences and similarities between draft-legal sprint and Olympic distance triathlon and non-draft IRONMAN 70.3 and IRONMAN distance racing and training.
  • Arild's top tips for age-groupers.

Sponsored by:

Precision Hydration

Precision Hydration
One size doesn't fit all when it comes to hydration. Take PH's free Triathlon Sweat Test to get personalised hydration advice tailored to what you're training for. Use the promo code THATTRIATHLONSHOW15 to get your first box for free!

The finest triathlon wetsuits, apparel, equipment, and eyewear on the planet. Trusted by Lucy Charles, Javier Gómez-Noya, Flora Duffy, Mario Mola, and others. Visit roka.com/tts for 20% off your order.


February training of the Norwegian national team

05:48 - 

  • This is the only training camp of the year at sea level, and also the only camp with the entire national team including including the juniors.
  • Based on this, the training for this particular camp will be rather different, however, in general we do not intend to do any major changes in the training just because it’s an Olympic year.


We do what we know has worked well before.

    The camp is a chance for the athletes who are all based in Norway to come out and do all the training outdoors.


Even though this is early in the year, the athletes should come well prepared to the camp and have had at least two months of good structured training.


Mostly we are doing plenty of low intensity volume here, but of course some interval sessions is performed as well, in general around threshold.

    For those who are going to race in Abu Dhabi in five weeks are also doing some even higher intensity workouts.
  • Most of the athletes in the national team are very close to race fitness almost every point of the year, compared to others we do not take any longer off season break and let the fitness shrink substantially during the year.

    This year, in total we had two weeks of no structured training after the season ended.


We also tend to start the training rather early with an altitude training camp in October.


One should also point out that this was a very long season for Kristian and Gustav as they among other races raced super league triathlon and Kristian also did Bahrain 70.3.

    Of course we want to peak fitness wise on the Olympics, but we believe that having a high level of fitness throughout the whole year will help us achieve that.

  • In terms of how we train throughout the year, this can vary slightly.

Plenty of low intensity volume and threshold intervals are constant ingredients all year around in our training regime, but closer to the races we use to do higher intensity intervals such as VO2max intervals and specific race pace work.

  • In the preparations for the Olympic test event last year, we did some extensive heat acclimatization in Thailand leading into the event, which we learned was a little bit too hard on the athletes and things didn’t quite work out as we had hoped on the Olympic test event due to this.

    This is something that we of course need to change leading into the Olympics in August, and we have also come up with a new plan that we are certain about will work very well.


During the heat acclimatization camp in Thailand we also did extensive testing, especially of core temperature during very high intensity work, this we learned a massive amount from, one of those things being that one cannot push too hard in very hot conditions.

  • For this year we have focused much more on intensity in the swimming as we for the first time had the chance to measure VO2max in the water and we saw that the athletes didn’t have as high VO2max while swimming as we had anticipated, and that this probably was the reason for why we were loosing a little bit of ground on the swim legs in the races.


It seemed that the high swim volume didn’t impact the VO2max as much as we had anticipated and therefore we decided to restructure the swim training towards more intensity.

Heat acclimatization for the Tokyo olympics

22:12 -

  • I think heat acclimatization is massively important.


One cannot train both as much or as hard in hot conditions as one is used to.

  • When arriving to a hot environment, the HR and RPE of the athletes is much higher at every given pace or power than what they are normally used to, this tells us that the heat has a massive impact on the body.

    In the beginning of a heat acclimatization camp, we let HR and RPE dictate the training and the pace and power will be what it will be.


Most athletes tend to go a little too hard in the beginning of heat camps.

    We also pay extra attention to the nutrition and hydration part in the heat, one tend not to want to eat as much in the heat and the amount of liquid that is required to take in, in order not to get too dehydrated is often much bigger than you think, and you also need to adapt the gut to take in this large amount of liquid.

  • Some data indicates that one tend to utilize more carbohydrates when exercising in hot conditions, however, we do not make any major changes to the athletes diets based on this.


However, we are really diligent when it comes to the diet and the first week of our heat acclimatization camps we have our nutritionist on site to help us make sure that all the athletes are getting in the right track nutrition wise.

In general, this year the athletes have been taking in more carbohydrates than before.

  • In Norway we are quite relaxed when it comes to weight and nutrition.

    That said, we do have a nutritionist that works very closely with the athletes, but the main focus for our nutritionist has been to ensure that the athletes are getting sufficient amount of calories in rather than holding back.

    I have never so far encountered a situation where it has been recommended to initiate a controlled weight loss.


At this point, I think the Norwegian athletes all have a body composition where they perform at their maximum, none of them would probably gain any performance advantages by gaining or loosing a few extra kilograms.

Intensity control during training

35:48 - 

  • We started by implementing a very strict intensity control during our training very early on as we started to develop our Norwegian triathletes.


We had a very long term perspective as we started to build our team of Norwegian triathletes, the goal was to build healthy and sustainably fit athletes.

    In order to do this, the idea was to do plenty of volume and then it came rather naturally that the intensity had to be very low for the majority of the training sessions.

    Consequently, when we do easy training the blood lactate levels should at least be below 1.0 mmol/l, and this we monitor rather closely during a lot of our sessions.
  • Also during the interval sessions, we make sure that these are performed at the right intensity.

Once again, we let the blood lactate levels determine the intensity during many of our interval sessions.

  • We consider three training zones to be of special importance: the FatMax Zone, anaerobic threshold (probably the most important one) and VO2max.

  • Be believe that having as high of an anaerobic threshold as possible is extremely beneficial in almost all triathlon race situations.

    Even though you manage to hold the same pace as someone with a higher anaerobic threshold, that person will have to activate anaerobic processes to a larger extent and that will at a higher rate empty the glycogen stores of that athlete.

    Having a high anaerobic threshold also seems very crucial in order to utilize fat as a fuel at all sub maximal intensity levels, which is very beneficial in longer events.

    When we do anaerobic threshold training, we typically aim for lactate levels between 2.5-3.0 mmol/l on the intervals.
  • In order to determine the lactate threshold, we have developed a standardized ramp test comprising of 8x6 min, which is a considerably longer test protocol compared to most tests designed to determine anaerobic threshold.


We make sure that we start below the first lactate threshold (aerobic threshold/LT1) and have at least two steps that are above the anaerobic threshold (LT2), we increase the power output on the bike by 5 % for each step or 1 km/h on the run.


In the swim we perform 8x500m.


When estimating the threshold according to these protocol, we typically find that the anaerobic threshold lands around 2.5-3.0 mmol/l lactate rather than the typical 4 mmol/l, which is often used as a benchmark lactate level for the anaerob threshold.

    For this well trained athletes, I believe that it is crucial that every step is long enough so that any eventual lactate build up will be visible.


For age group athletes, these long steps may not be ideal as they may not express the fitness level to endure the full test protocol.

4 mmol/l of blood lactate would be significantly anaerobic efforts for my athletes.

    To measure VO2max, we do another test.

  • We have also started to track VlaMax as a parameter, even though we do not follow it as closely as VO2max and the thresholds yet.

    I have seen that the VlaMax is highly reactive to training and also very individual.

    For instance, after the WTS finals in Lausanne, both Kristian and Gustav’s VlaMax was quite high as they were going into the 70.3 World Championships in Nice, so given that we had to be extra diligent when it comes to nutrition as we know that a fairly high VlaMax brings the carbohydrate consumption up.

    The VlaMax is still something that is quite new for us, and I do not possess that much knowledge about it yet, but it is something very interesting and I look forward to learn more about.

Training for age group athletes

58:40 - 

  • I think that many age groupers tend to down prioritize all the easy sessions and instead focus a little bit too much on the intensity.

    However, I still think that improving the anaerobic threshold (by performing threshold intervals) should be the highest priority for age group athletes as well.

    For many age groupers, doing extremely easy training would probably not be the best investment of the time.

    Then I would rather see that they do plenty of work around the aerobic threshold and/or their Ironman race pace (if the Ironman distance is the main target).

    It is, however, important to make sure that you’re fresh for the important interval workouts.
  • Sometimes, I think many amateurs could benefit from skipping the structure of their training and just go out and do the kind of training that they enjoy most, most age groupers live a much more stressful life than the professionals and the importance of relaxing and just enjoy yourself becomes even more crucial.

Confidence level before the WTS final and the 70.3 worlds

1:04:05 -

  • Before the 70.3 World Championships I said that I would be surprised if Gustav or Kristian didn’t win this race given the fitness level they had displayed in training prior to the event.
  • I was not equally certain that some of them would win the WTS final in Lausanne even though I knew that their chances were really great.


In the Olympics test event Casper (Stornaes) was second and unfortunately Kristian didn’t finish due to a bad cycle crash during the race.

    However, in the training leading up to the Tokyo test event, Kristian was the Norwegian showing the best shape, so if he hadn’t crashed there, I am pretty certain that he would have won that race.

    Before the WTS final, it was all a matter of time if he would be sufficiently recovered from the bike crash and that he hadn’t lost too much of fitness due to it.

Level of competitiveness in WTS and 70.3 racing

1:07:00 -

  • I would say that the level of competitiveness in the top is rather similar between the WTS and the half Ironman distance.
  • All the athletes racing the WTS display an incredibly high level of fitness and maybe only 1/3 of the pro athletes racing the 70.3 world championship have a similar fitness level to that, but in the absolute top I think it is rather equally competitive.

Learning from long distance racing for short short course triathlon

1:08:35 -

  • As a short course triathlete, it is probably easier to enter and perform well at a long distance triathlon event than vice versa.

Basically, the swimming of most long course triathletes is simply not fast enough.
  • One thing that we have learned from long course racing is the importance of a strong cycling capacity, and we try to incorporate this into short course racing.

Advice to age groupers

1:10:45 -

  • Most amateurs pay too much attention to the small details and forget the most important and biggest pieces of the puzzle.
  • Many age groupers are so incredibly structured in every way of their lives so sometimes they should just go out and train without heart rate monitors, power meter or any other equipment and just relax and enjoy the training1

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. 

I sincerely want you to contact me to

  • Send me feedback
  • Give constructive critic​ism 
  • Request topics and guests for the podcast
  • Send me your triathlon-related questions 
  • Tell me that you've rated and reviewed That Triathlon Show so I can give you a shout-out on the show and tell you how much it means to me!
Subscribe to That Triathlon Show and never miss an episode!


Let's discuss this episode and the topic in general. Post any comments or questions in the comments below. I'll be here to reply and take an active part in the conversation, so don't be shy! 

Insert Image
Insert Content Template or Symbol
Insert Content Template or Symbol
Quick Navigation

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.

If you are a long-time listener and appreciate the value the podcast brings, please consider taking a couple of minutes for leaving a rating and review on iTunes/Apple Podcasts, or wherever else you can think of leaving a rating and review.

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

Explore our products and services