Mona Fartleks

What the…?!

There’s lots of information about what the Mona Fartlek session is so I’m not going to repeat it here: look it up yourself.

My thoughts

I think of a Mona Fartlek session as a tempo session with intervals at VO2max thrown in. This makes the session “hard efforts” with “comfortably hard” recoveries… a great, well structured 20 minutes to do once per week in a well balanced training plan.

If you like, you can read VO2max as “hard”; and tempo as “recovery”.

The plan

  • Warm up for 15 to 20 minutes, or as long as you need (don’t skimp here!)
  • 2 × (90 seconds VO2max, 90 seconds tempo)
  • 4 × (60 seconds VO2max, 60 seconds tempo)
  • 4 × (30 seconds VO2max, 30 seconds tempo)
  • 4 × (15 seconds VO2max, 15 seconds tempo)
  • Cool down for 15 to 20 minutes, or as long as you need (it’s just as important as the warm up!)


If you do this session regularly, it provides an excellent metric for your running fitness. You can attain a “score” for your session using the distance covered in the 20 minutes of the formal sequence. Getting a good score means doing the right efforts at the right times: go too hard on the VO2max parts and you’ll blow up before the finish. Go too slow on the tempo recoveries and you’ll not go as far during the session. “Plan your run and run your plan” is sagely wisdom which is very applicable here!

I don’t know my paces

If you’ve got no idea what your running paces should be, I’ve built a calculator to assist your run planning. You can also use it to help plan your next assault on a PB distance.

Mona Fartlek Effort Calculator


  1. Use the GOAL value to set your goal distance for the session
  2. Use the EFFORT PERCENT DIFFERENCE value to change the difference in pace between the VO2max pace and the tempo recovery pace.
    • The difference value itself is not important, all you need to do is adjust the value until you get a combination of fast and slow paces which allow you to still achieve the goal distance. Of course, if you set the difference value to zero, you will get the pace required to run the goal distance at a constant pace; if you set the value ridiculously large, you’ll get a VERY fast pace and a VERY slow pace which probably wont be that realistic.
    • Until you’ve done a few of these sessions, be conservative. Later, if you want to run the fast parts as little harder then set the difference value a little higher.


Effort Percent Difference

VO2max pace : 4:23 min / km

Tempo recovery pace : 4:55 min / km