Fartlek Training: What It Is, Why It Works and 5 Sessions to Try
Fartlek training is a way to practise pace changes without the rigidity of intervals. You run continuously and add fast sections whenever you like, by time, by terrain or by feel. It is one of the most rewarding sessions for improving speed, and you can do it anywhere, without a track or a precise watch. This guide explains what it is, how it differs from intervals and five fartlek sessions for your week.
What fartlek training is
The word comes from Swedish and means speed play. According to the history of the method, it was developed in the late 1930s by the Swedish Olympian Gösta Holmér for his country’s distance runners.
The idea is simple: during a continuous run you alternate fast and easy sections without stopping. Unlike intervals, the recovery is also running and the structure can be as free as you like.
How fartlek differs from intervals
In intervals, the reps and recoveries are measured to the metre or second, and you often stop or walk between repetitions. In fartlek there are no breaks: the pace drops but you keep running, and you can decide on the go how long each change lasts.
That makes it easier mentally and more like a race, where the pace rises and falls with hills, overtaking or the wind. Intervals are still better when you want to work on an exact pace, as I explain in the guide to 10K interval workouts.
What fartlek training is good for
It improves your ability to change pace and recover while running, works your aerobic system and your higher-intensity capacity at the same time, and breaks the monotony of easy runs. It is also a good way to bring speed back after a break, or to start with intensity if you have never done intervals.
Five fartlek training sessions
In all of them, warm up for 10 to 15 minutes with an easy jog and finish with 5 to 10 minutes of cool-down. If you are not sure how to warm up, see the guide to warming up before running.
1. Classic fartlek by feel
Run for 30 or 40 minutes and add 6 to 10 pace changes whenever you feel like it: to the next lamppost, to the top of the hill or for the length of a song. Each change lasts 20 seconds to 2 minutes, at a demanding but controlled pace. It is the original version and the most fun.
2. 1-1 fartlek
After the warm-up, do 10 blocks of 1 minute fast and 1 minute easy, without stopping. It is the best session to start with, because it is easy to remember and to adjust: if it is hard, do 6 or 8 blocks.
3. Pyramid fartlek
Fast sections of 1, 2, 3, 2 and 1 minutes, with half the time easy between them. The pace of the longer sections is a little slower than the short ones.
4. Mona fartlek
A 20-minute session named after the Australian marathoner Steve Moneghetti: 2 times 90 seconds fast and 90 easy, 4 times 60 and 60, 4 times 30 and 30 and 4 times 15 and 15. The short sections are faster. It is demanding: save it for when you have experience with pace changes.
5. Terrain fartlek
On a hilly loop, run each hill hard and recover on the flat and the descents. It combines fartlek with uphill strength work, and it is very useful if you are preparing a hilly race. There are more ideas in the hill training guide.
What pace to use for fartlek training
The fast sections go between your 10K and 5K pace: demanding, but not a sprint. The easy ones, at comfortable easy-run pace. To be precise, work out those paces with the training pace calculator, but in fartlek feel matters more than the watch. The guide to pace and speed explains the difference between the two.
How to fit fartlek training into your week
A fartlek session counts as your quality session, so do not do it on the same day as, or the day before, intervals or your long run. If you run three days, you can alternate a week of fartlek and a week of intervals. In the 5K training plan and the 10K training plan you can swap an interval session for a fartlek of similar length.
Conclusion
Fartlek training alternates fast and easy sections without stopping, with a structure as free or as measured as you like. It improves pace changes and speed in a way that is easier to handle than intervals, and fits as a quality session once a week. Start with the 1-1 or the classic by feel and save the Mona for later.
FAQ
What is fartlek in running?
It is continuous pace-change training: during a run you alternate fast and easy sections without stopping. Its name means speed play in Swedish.
What is the difference between fartlek and intervals?
In intervals the reps and rests are measured and you often stop between repetitions. In fartlek you recover while running and the structure can be free.
How long should a fartlek training session be?
20 to 40 minutes for the main part, plus the warm-up and cool-down.
How often can you do fartlek training?
Once a week, as a quality session. If you also do intervals, alternate the two or leave at least one easy day between them.
What pace should fartlek changes be?
Between your 10K and 5K pace for the fast sections, and comfortable easy-run pace for the easy ones.
