Fartlek ▷ Improve Your Running with Speed Work

man running downstairs

by Ruth Spelmeyer,  400m sprinter and adidas athlete

Have you ever heard the term fartlek?

The term fartlek…

…comes from the Swedish word fart (speed) and lek (play). The fartlek was developed by Swedish track and field athlete Gustaf Holmér in 1930.

This speed workout is an extremely effective type of training for mid- to long-distance runs.

What is fartlek training?

The original fartlek training involves frequently increasing and decreasing the running speed and thereby the training load when running outdoors. The effort and interval duration are not planned; these are determined by the terrain or running surface and can be alternated according to how you feel during the workout. The effort then varies throughout the workout.

Good to know:

The goal of fartlek training is to play with speed in a natural way. Monitoring your heart rate and time is secondary – many runners find this more motivating.

happy woman in a group of runners

What are the benefits of fartlek?

Unlike in an endurance run, during fartlek the body has to constantly adapt to different speeds and surfaces. This has a lot of advantages:

  1. The continuous change between effort and recovery increases endurance when your heart rate is in the upper range. The body is forced to push itself harder for longer periods. This boosts the overall endurance level.
  2. Changing pace and surface also works the tendons and muscles more. The muscles get stronger, which can prevent injuries.  
  3. Running downhill on different surfaces trains balance, coordination, and flexibility.
  4. With fartlek training you can learn about your own limits in a playful way. Plus, by changing your speed so often, you practice passing other runners. This can be helpful during a race or final sprint to the finish line.

Fartlek vs. interval training – what’s the difference?

In interval training the runner follows a defined schedule of sprints, while flexibility is prioritized during fartlek. There are only two speeds in interval training; this requires less concentration, unlike with fartlek, where the runner has to pay attention to both the pace and the terrain. The two training methods also differ in their demands on the body: fartlek uses different muscle groups and improves coordination.

man running outdoors

Training: an example of a fartlek workout

Two different versions of fartlek have emerged over time:

  • The original Swedish fartlek explained above is great for anyone who wants to leave their watch at home sometimes when they train. Here you focus on how your body feels.
    Example: Run about 15 minutes at 75 percent of your maximum heart rate – 40 meter sprint – 5 minutes at 60 percent – 3 minutes uphill at 85 percent – 2 minutes downhill at 65 percent – 1.5 minutes at 90 percent, etc. Wrap it up by cooling down at 60 percent (HR Zone 1).
  • In the Polish fartlek, the changes in pace are planned beforehand. This form of training can be a lead up to interval training.
    Example: Run 2 minutes at 85 percent of your maximum heart rate – then 4 minutes at 60 percent – 3 minutes at 85 percent – 6 minutes at 60 percent – 4 minutes at 85 percent – 8 minutes at 60 percent  – 3 minutes at 85 percent – 6 minutes at 60 percent – 2 minutes at 85 percent.

Expert tip:

When doing sprint segments, it helps to pick an object in the distance and sprint to it. This way you have a clear goal ahead of you.

How can I integrate fartlek training into my workouts?

In fartlek training it is important to stay focused on the goal you have set for yourself. If you are training for a half marathon, your training should be focused on precisely that. It’s important to remember that if you want to achieve something specific in your training (e.g. a faster pace), fartlek does not make a lot of sense. In fact, you should stay away from fartlek training during especially tough sessions or active recovery workouts.

The playful quality of the fartlek is one psychological benefit that many athletes enjoy – it can add a new motivational element to your training plan.

Tip for beginners:

Beginners need to be especially careful not to push themselves too far during fartlek. Get familiar with your limits gradually, so you don’t get overwhelmed and demotivated.

Check out these tips to run faster:

About Ruth:

portrait of woman in Adidas clothes

Ruth Spelmeyer is a 400m sprinter and adidas athlete. Her greatest athletic achievement so far was participating in the 2016 Olympic Games in Rio. In addition to running, Ruth is studying psychology, enjoys cooking and traveling.



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