A woman running at speed with a motion-blurred background


  • A great session for hitting a variety of paces and reaping a variety of training benefits
  • Useful for runners who have lost a bit of fitness and want to start introducing slightly tougher sessions

Fartlek is Swedish for "speed play". And that provides a great description of how the session should be carried out. The goal is to run at a variety of paces over the course of your session.

Fartleks are sometimes referred to as "unstructured interval training".


None required, but a GPS running watch is useful to keep an eye on your paces.

The Session

Simply go out and include a mix of paces in your run. The spirit of fartlek running is to make things up as you go along, so the intensities you run at and the length of time of each section is entirely up to you. However, it's sensible to make the start of the run fairly easy to ensure you're well warmed up, and an easy five minutes at the end can serve well as a cool down.

Real World Example

Following a 10-minute jog to warm up, you could run hard up a hill and jog down the other side, take a few easy minutes, sprint between alternating lamposts for the length of a street, then take a few more easy minutes before spending some time practising accelerations and finishing up with a moderately hard 10 minutes followed by a 5-minute cool down jog.


Try not to plan ahead too much. You'll have a much more enjoyable and stress-free session if it's truly unstructured and you act on a whim throughout.


Remember to spend the first section of the run warming up before your session and the final section cooling down.