Training
What is fartlek training?
The Swedish "speed play" that mixes surges into an easy run: the benefits, example sessions, and how it differs from intervals.
Fartlek training is Swedish for "speed play": unstructured bursts of faster running woven into an otherwise easy run. You surge to a landmark, ease back until you recover, then surge again whenever you feel ready. It blends easy running and speed work into one continuous, playful session with no track and no rigid rules.
The freedom is the whole idea. Instead of counting reps, you read the road and your body: a faster push up to the next tree, a floaty stretch of recovery, a longer surge along a flat. It keeps intensity in your week while keeping the run relaxed and fun.
Benefits of fartlek
Because the surges push you above easy pace, fartlek develops your speed and aerobic power much like structured intervals do, but the continuous flow adds something extra. You learn to recover while still moving, and to change gears on demand, which is exactly what races throw at you when the pace lifts, a hill arrives, or a rival makes a move.
It is also low-friction. You do not need a track, a lap counter, or a strict plan, just a route and a willingness to play with pace. That makes it one of the easiest ways to add quality to a week without the mental load of a precise workout.
Fartlek vs intervals
Both mix hard and easy running, but they trade precision for freedom. Interval training locks in the distance, the pace, and the recovery so you can hit specific target paces on repeat. Fartlek leaves all of that to feel. You vary each surge by landmark and mood. Use intervals when you need to sharpen an exact race pace; use fartlek when you want the benefits of speed work with less structure and more play.
Example fartlek sessions
Beginner: landmark surges
On an easy 25 to 30 minute run, pick out lampposts or trees. Run harder to one, jog easy to the next to recover, and repeat when you feel ready. Keep it playful, no counting required.
Intermediate: timed pyramid
After a warm-up, surge for 1, 2, 3, 2, then 1 minute, with equal easy running between each. The varied surge lengths train a wide range of efforts inside one flowing run.
Advanced: race-simulation surges
On a 45 to 60 minute run, throw in 6 to 8 firm 2-minute surges at close to threshold effort, jogging just enough to recover between them. This rehearses lifting and settling the pace under fatigue.
How to pace your surges
The fast parts should feel challenging but controlled, not a flat-out sprint. To anchor "moderate" and "hard" to real numbers, work out your easy, tempo, and interval paces with the training pace calculator and use the faster bands as a loose target for your surges.
Frequently asked
What is fartlek training in simple terms?
Fartlek is Swedish for 'speed play'. It means mixing bursts of faster running into an otherwise easy run, in a loose, unstructured way, you speed up to a lamppost, ease back until you recover, then surge again whenever you feel like it. It blends easy running and speed work in a single, playful session.
How is fartlek different from interval training?
Interval training is precise: fixed reps, fixed distances or times, and fixed recovery, usually measured on a track or watch. Fartlek is deliberately loose. You vary the length and intensity of your surges by feel, using landmarks instead of exact numbers. Intervals build specific paces; fartlek builds speed while keeping the run relaxed and adaptable.
What are the benefits of fartlek?
Fartlek improves your speed, aerobic capacity, and ability to change pace, all while feeling less rigid than track intervals. Because it flows continuously, it teaches your body to recover on the move and to surge and settle, a skill that pays off in races. It is also a great way to add intensity without needing a track or a strict session plan.
How often should I do fartlek runs?
For most runners, one fartlek session a week is plenty. It counts as one of your one or two harder efforts. Keep the rest of your week easy so the surges stay high quality. Beginners can start with just a handful of gentle pickups inside an easy run and build from there.
What pace should the fast parts be?
There is no single correct pace, that is the point of fartlek. The surges should feel faster and challenging but still controlled, not all-out sprints. If you want a reference for your easy, moderate, and hard efforts, work out your training paces and use the faster bands as a guide for the surges.
Play with pace, on purpose
Fartlek adds speed. A plan puts it in the right week.
Gritup builds an adaptive running plan that mixes easy volume with the right dose of speed work, so your hard days sharpen you instead of wearing you down.