There has always been, and still is, hot discussion about the type of interval training and how many times in a week one should do them. Some use blocks, for example every day for 10 ten days in a row. It’s often called “trøndeversjonen” (The Trøndelag version) after a researcher in Trøndelag that found out that training intervals 10 days in a row can have a big effect.

For others it’s the more traditional variations that work, especially those with 2-3 intervals in a week, and usually a little scattered across seven days. I share the last philosophy, which is, after all, the one I have the most experience with.

In addition to these conflicting versions there is a lot of discussion about the intensity scale, where research shows that threshold intervals [level 3] is most effective for oxygen uptake. I suppose it is natural that many throw themselves on that theory. It is definitely the most comfortable and convenient…

And maybe it is such that the theory of building a little better oxygen uptake by doing threshold intervals actually has something going for it. My philosophy, however, has always been that intervals are max speed, which is all about only one thing for me; to get absolutely as stiff as possible.

When I say that the research is right about oxygen uptake with threshold intervals while not following the principles myself, it stems from the fact that I believe intervals have to do with more than that, especially for cross country skiers.

The research is important and from time to time provides progress, but also quickly becomes narrow. Thus, it is important that you are able to maintain focus on the bigger picture. What is important out there on the trails? And for me the interval workouts had to do with three important things:

For the first: Capacity. I train intervals to build the capacity of the heart and lungs, and have experience that it happens with maximum speed.

For the second: Technique. Speed records are being set all the time, and you don’t win races without feeling lactic acid. Some times I had lactic acid in almost every single uphill. And so the challenge was to maintain good technique even if my body was stiff as a board, so that I didn’t loose time. And so I had to train that way. Work on technique with lactic acid up to your ears. The entire summer and fall.

Remember this moment? I do.

For the third: Pain. An old myth says that when you believe you are finished, you still have 30% left. I don’t know if it’s true or not, but in any case I believe that the pain threshold can be stretched to a very large degree. It might be a little individual, and also dependent on the day’s fitness, but still something that can be trained.

Thus, I wish not to refute the research and those that believe that threshold intervals give higher oxygen uptake, that is not my point. But I believe that with what I gain in a little extra oxygen uptake, I lose in the other two important elements that I consider to be just as decisive in a competitive environment. Therefore I stand firm with my theory that intervals are about full tilt from the first meter so as to train yourself to withstand lactic acid and maintain good technique with lactic acid, in addition to strength and capacity.

So we come back to the fact that there are an uncountable number of theories about how long intervals should be. My experience is that it’s not so important. If I was going to train short, long, few or many intervals and short or long rests, didn’t matter at all. It was the energy I put into the workout that actually became the most important.

My intervals have been characterized by tempo. That is, if I’ve had 10 X 2 minute intervals, I’ve had maybe three minutes rest in between. Always as long or longer rest than the interval, to ensure that I could hold the pop and speed during the intervals.

I have also stuck with relatively short intervals. The idea behind this is that if I were to break up a typical race, it ends up just being made up of many short intervals followed by rests. Also, the longest continuous rise is seldom over two minutes. In longer races it’s of course otherwise, and so you have to look at it appropriately.

Nevertheless, my experience is that it is wasted energy to ponder very long about how interval workouts should look. Find a form that works for you, so that you put all your energy and your all your soul into the work.