Interval training is the most intense form of endurance training. Before discussing the different versions of interval training in more detail, let’s recall the term’s meaning.

Interval training is a form of training that involves a series of low- and high-intensity exercises with rest or recovery periods. The high-intensity periods are usually at or very close to anaerobic performance, while the recovery periods are low-intensity exercise. The variation in intensity engages the myocardium, gives the cardiovascular system a workout, improves aerobic capacity, and allows for more prolonged and intense activity. Interval training improves the lactate threshold, increases VO2max or oxygen uptake, and thus enhances skiing speed. 

When talking about improving the lactate threshold, interval training builds a fast and efficient base pace. The lactate threshold is the point at which the body begins to accumulate lactate faster than it can remove it. Training at this level teaches the body to use lactate as energy so that you can ski faster without the ‘burning feeling.’

Two examples of lactate threshold exercises are “threshold speed” or speed endurance exercises and “threshold intervals” or intervals. Speed endurance training is, of course, of longer duration, i.e., maintaining a threshold or near-threshold pace for a relatively long period of time. Intervals, on the other hand, are shorter, faster-paced exercises.

An example of an interval workout is six repetitions of 5–7-minute intervals (6 x 5-7 minutes) at lactate or anaerobic threshold level, with a two-minute recovery between intervals. Of course, a good initial warm-up should be done before the interval workout and a proper cool-down after the session. Because the body and muscles are given time to recover between intervals, the pace of the intervals is much faster than in a speed endurance workout. Interval training also allows you to vary the length of the intervals, for example, starting with shorter ones and increasing their length along the way. Still, the shorter the intervals, the closer you get to VO2 max intervals.

These ‘oxygen uptake intervals’ maximize the amount of oxygen transferred from the lungs to the muscles, strengthening the heart and capillary network. These intervals load the body beyond the race pace, making it easier to maintain a high race pace and allowing intervals and sprints during the race if necessary.

These intervals are much shorter than threshold intervals, ranging from 2-5 minutes, depending on the skier’s performance level. One classic example of a VO2max interval workout is four repetitions of four-minute intervals (4 x 4 minutes) over the lactate threshold. This pace is slightly below the maximum pace, and the intervals should often be done on the uphill to keep the work intense throughout the interval. Recovery is usually at least as long between intervals to allow the body to recover sufficiently before the next interval. Naturally, the workout includes a good initial warm-up and a final cool-down. Competitive skiers usually do these interval workouts closer to their competition season and continue them between races. This type of training was one of Marit Bjørgen’s main workouts during autumn.

In addition to the abovementioned intervals, many top skiers do longer intervals with a controlled threshold. Top skiers often have very short recovery times between sets. Johannes Høsflot Klæbo does 5 x 12 min intervals with a few minutes of recovery between them. Some long-distance skiers, such as Morten Eide Pedersen, do up to 20-minute intervals with recovery between them as short as a minute. Such a workout is already more of a speed endurance workout. Still, the short rest in between allows for a more efficient performance in the intervals compared to a continuous speed endurance workout. Maastohiihto.com recommends that instead of an hour of constant speed resistance training, you try a 3 x 20 min workout with 2-3 min rest in between.

One popular interval training exercise is the pyramid workout, which has different versions. In the Mallorca training camp article, Maastohiihto.com highlighted the Team Ragde Charge team’s Vasalopp Pass workout, where after two hours of hard roller skiing, they did pyramid intervals starting at 10 minutes and shortening the intervals by one minute at a time so that the last one was one minute long. In this exercise, the recovery was one minute. The pyramid exercise is worth a try as it is often more meaningful than repeating the same length of intervals.

There are many different types of interval training. However, remember that the first few intervals should not be too hard. If too much lactic acid builds up at the start, recovery will take too long, and the exercise will be ruined. Interval training is successful if the last intervals are the fastest or at least very close to it.

Here is an article on interval training on the Runner magazine website (in Finnish), which can give you some tips for your training, especially if you want to do interval training while running.

Are you interested in training for long-distance and traditional cross-country skiing? Click HERE and read more.