High intensive interval training for Norseman? - Norseman

High intensive interval training for Norseman?

How do you train to best prepare for a long-distance triathlon like the Norseman? With finisher times spanning the range of 10-20 hours, it is a long haul.

Published: 12.Feb.2020

By Martin Bonnevie-Svendsen.

Martin is a medical doctor at Oslo University Hospital. He is also part of  the research team studying the effects of extreme racing conditions on athletes at Norseman. Aside from being an avid amateur cyclist, his great passion is helping athletes better understand and make use of exercise science. @wattkg


For such events like Norseman, low intensity endurance rides and long intervals at moderate intensity close to race pace are often considered cornerstones of the preparation. But what about high intensity training? Could the shorter and more intensive brother of the threshold interval possibly offer additional benefits to performance?

Long-distance triathlon is a game of conservation. You want to achieve the highest possible speed for the least amount of effort. As such, you would want to train to be able to:

  • maintain a given speed for a longer duration
  • transfer your energy more efficiently into the water/pedals/ground
  • increase speed without increasing the oxygen or fuel consumption

In physiological terms the properties above can be summarized as muscular endurance, gross efficiency and work economy.When you are able to improve these properties, you stand a better chance of achieving a strong finish.

Experience would suggest that long-distance triathletes do a lot of high volume training at low intensity. Additionally, they tend to favor intervals of long duration at moderate intensity – so called “tempo”, “sweetspot” or “threshold” intervals. This observation is also backed by longitudinal studies.

The above is perfectly aligned with the principle of specificity – you need to practice the relevant skills required for a strong race performance. In other words, “train as you race”. Furthermore, a recent study on 18 recreational-level triathletes found that training time at moderate intensity (between ventilatory threshold 1 and 2) was related with better performance in the Half-Ironman distance.

As such, it appears that the use of moderate training for long-distance triathletes is reasonably well founded.

But it´s all low intensity.

For a long time, I have wondered whether or not high intensity training (HIT) could provide long-distance triathletes with potential benefits. The opposing argument is blatantly obvious:

“The duration of the Norseman event dictates a race intensity well below anaerobic threshold. Why then, should you consider training at intensities close to VO2 max and above anaerobic threshold?”

Well, I can think of a few potential reasons.

1. For starters, it has been shown that high intensity interval training in combination with low intensity training not only improves VO2 max. It also enhances performance and work economy at lower intensities.

This makes sense when you think of it. If you are able to increase your VO2 max, of which cardiac stroke volume is a big determinant, your enhanced ability of oxygen delivery to the muscles would be expected to benefit performance also at lower intensities. Put shortly, you should be able to work at a given submaximal power/speed at relatively lower intensity than before.

2. The second reason I can think of involves the principle of variability. Interestingly, an observational study on 13 recreational triathletes report that increased training time at moderate intensity was associated with a slower finishing time at an Ironman race. It could be noted that these athletes spent 28% of their training time at moderate intensity, which was more than what was reported in the previously mentioned 18 athletes who achieved a positive correlation between moderate training and performance.

Some authors have suggested that big volumes of moderate training induce greater autonomic stress, which may increase the risk of overtraining. In line with the principle of variability, could it be that it is beneficial to break up frequent moderate training with other modalities in addition to low intensity training?

3. The demanding nature of the Norseman race track might carry some relevance with regards to high intensity training. The cycling course in particular involves several climbs of significant incline. As most of us will have experienced, steep climbs tend to force you into the higher intensity zones.

Furthermore, you may be required to produce significantly higher than average power outputs during overtaking other athletes on bike leg. Short high intensity intervals appear to enhance capacity in the intersection between aerobic and anaerobic work. They also seem to improve the ability to tolerate higher levels of blood lactate.

We could speculate that introducing elements of short-style HIT training may allow you to better tolerate sudden spikes in power outputs throughout your long-distance race.

4. We could also ask if the enhanced ability to produce high power outputs, combined with greater lactate tolerance could benefit the execution of your moderate intensity training. In other words, training to enhance your training.

It has been shown that even a brief 3-week period of short HIT intervals will induce the aforementioned training adaptations. After such a period, we could speculate that you would then be able to utilize your enhanced lactate tolerance to perform your moderate training at higher power outputs and potentially higher lactate levels. Which in turn may allow greater training adaptation.

I should add that I have not seen data to support this hypothesis. However, it makes for a compelling thought.

5. Finally, some interesting work has been done on the topic of moderate and high intensity training and the ability to endure pain.

Stephen Cheung, who is a rather accomplished author within the field of exercise science, has discussed the findings of a study examining this relationship. He suggests that data support the notion that high intensive training has a greater capacity to train the tolerance for discomfort than does moderate training.

Granted, it may be premature to draw bombastic conclusions regarding pain tolerance based on a single study.

Nevertheless, when you tally up the total, there are quite a few plausible arguments for why you might consider including periods of high intensity training in your preparations for Norseman or indeed any of the other XTRI World Tour races.

The only thing that is 100% certain is that the last word on this topic has yet to be written.

© Torgeir Storflor Moen / nxtri.com

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