Fartlek training: what it is and how to start

Fartlek is Swedish for "speed play": one continuous run that mixes faster surges with easier running, without stopping in between. Swedish coach Gösta Holmér developed it in the 1930s for cross-country runners, and it is still one of the simplest and most fun ways to get faster.

How fartlek differs from intervals

In interval training you run set reps and then recover, often walking or standing. In a fartlek you keep running the whole time: the recoveries are easier running, not rest, and the surges can be as long or as short as you like. Classic fartlek was run by feel on trails and roads, picking the next tree or lamppost as the end of a surge; structured fartleks fix the surges by time, so you know what's coming.

What it trains

Because you never fully stop, a fartlek trains you to change pace and to recover while still running, which is how races feel. Short surges sharpen speed and form, longer ones build stamina, and since every fartlek is different, it's an easy way to bring speed into your week without a track.

Your first fartlek

  1. Warm up with 10 minutes of easy running.
  2. Run 8 surges of 1 minute at 70–80% effort, each followed by 2 minutes of easy running.
  3. Cool down with 5 to 10 minutes easy.

Keep the surges controlled: you should finish feeling you could have done one more. Not sure how 70% feels? See the effort scale.

5 fartlek workouts, from easy to hard

  • Stoplight Play: a playful 15-minute run that shifts through color "gears", good for a first try.
  • Fartlek Game 2–1–1–2: surges of 2 and 1 minutes with short floats, about half an hour.
  • 10-20-30 Copenhagen: blocks of 30 seconds slow, 20 seconds moderate and 10 seconds fast, from a University of Copenhagen study.
  • Oregon 30/40s: 30 seconds fast and 40 seconds steady, nonstop.
  • Mona Fartlek: Steve Moneghetti's 20-minute classic of 90-, 60-, 30- and 15-second surges, with a steady close.

How often

Once a week is enough for most runners, in place of another hard session and with easy days around it. A fartlek is still a hard workout: after a long break or an injury, start with shorter, gentler surges.

Run it in Fartlek

The app is named after it: the library has 7 fartlek workouts, and Pete, the AI coach, can build one to your liking, like "30 minutes of fartlek with short surges", with an effort target and a cue for every change of pace.