Want to combine speed training with endurance training in one workout? Fartlek runs could become your next favorite way to train.

Read on to learn everything you need to know about fartlek training. We’ll see how it differs from other runs, review its benefits, and show you how to do it. But first…

In This Article

What Is a Fartlek Run?

Let’s begin with a simple fartlek definition. Fartlek is running at different speeds and intensities to boost your fitness.

It’s a type of high-intensity interval where you may vary your pace, but you run continuously without stopping.

For example, you can run for 5 minutes or 500 meters intensely. And then run lightly for the same time or distance before switching to a moderate pace for, say, 3 minutes, and so on.

Calling fartlek a form of play isn’t an overstatement. It lets you focus on running by feel rather than adhering to a strict structure.

Fartlek isn’t only a fun and interesting running workout. It mixes fast and slow, hard and easy running to increase your endurance. It’s also great for improving your running speed. Plus, it can boost your anaerobic threshold and has a host of other benefits. 

Although fartlek is similar to interval training, it differs in some key aspects.

Difference Between Fartlek Run and Other Speed Workouts

Unlike interval training, fartlek isn’t structured. Intervals combine short bursts of intense running with recovery periods when you jog or walk.

For example, when you do intervals, you may do 4 x 500-meter reps with recovery bouts in between lasting slightly longer than a rep. Fartlek involves continuous running without complete rest.

Fartlek also differs from tempo runs. You can run tempo runs at a comfortably hard pace, but they require a consistent pace based on your race speed. Meanwhile, fartlek lets you mix paces.

Benefits of Fartlek Training

There’s more to fartlek training than its element of play. Here are some of the best reasons to incorporate it into your workouts.

1. Speed and endurance

According to this meta-analysis of high-intensity interval training, fartlek can boost speed and improve the anaerobic threshold better than simple endurance training.

The anaerobic threshold is the exercise intensity level at which lactic acid starts building up in your blood. When this happens, it hinders your muscles’ ability to contract, slowing you down.

Another study notes the beneficial effects of fartlek training on your calf muscles. By building more calf muscle fibers, it helps boost your running endurance.

2. Close to the “Real”

Fartlek prepares you for the demands of a long-distance race. Tempo runs and interval training have their benefits. But in an actual race, you don’t get to stop and rest or run at a consistent pace from start to finish.

Fartlek simulates continuous running and natural pace variations. Because of this, fartlek is ideal for racers and sports training.

3. Variety and fun

Doing the same intervals can start feeling dreary after a while. The same goes for running at a consistent pace. More than feeling boring, it can become demotivating.

That’s when fartlek can save the day by adding variety and fun to your workouts. With fartlek, you can improvise as you go.

You can sprint to the red car parked at the entrance to the park. Then slow down to enjoy the view of the alley lined with old trees. Then speed up again for 5 minutes until you get to your favorite view of the lake.

4. Aerobic focus

Running through your recovery period after an intense run helps you build a stronger aerobic system. If you’re planning to race in a 5K or longer races, you’ll need plenty of aerobic energy.

Unlike sprinting, long-distance running requires a steady supply of oxygen to power up muscles. And it needs this to be consistent and adapted to the pace you’re aspiring for. Fartlek is great training for your aerobic system.

5. Burned calories

Like other HIIT workouts, fartlek can help you lose weight. You can burn more calories during fartlek runs compared to running at a consistent pace.

This happens because as you increase your speed, your body has to burn more calories to keep you going. And since you’re not stopping at any point in your workout but keep on going, you keep burning calories.

How to Do a Fartlek Run Workout

The beauty of fartlek is that you can alter your runs from one workout to the next. But it’s good to start with a typical fartlek run to see how your body responds to it.

  1. Begin with 10 minutes of running at a warm-up pace.
  2. Next, switch gears and run for up to 3 minutes at a race pace. Or sprint for 1 minute. After this, slow down to a slower jog pace but keep running. Don’t walk or stop.
  3. Alternate race-pace running with slow running for up to 7 or 8 repetitions. That would add up to a total of 16 to 32 minutes.
  4. After your last fast-slow pace change, end your session with a 10-minute run at a slow, cooldown pace.

Important: Integrate a warm-up and cool-down into your fartlek runs as described to reduce your injury risk.

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The best fartlek training app can help you build fartlek runs into your workouts and enjoy each one. If you’re new to fartlek, an app can help you get started more easily.

Tips to keep in mind:

  • Beginners start slow – If you’re new to fartlek runs, you don’t want to push yourself too hard. Allow for a few sessions that aren’t too demanding to get a feel for it. Your first fartlek shouldn’t feel exhausting.
  • Keep running You don’t want to stop at any point during your fartlek run. If you find you have to, you’re pushing yourself too hard. Reduce reps and/or slow down.
  • Be goal-focused – Adapt your fartlek to your overall running goals. Training for a marathon? Run longer at a pace closest to the race pace you want to achieve. Training for a 5K? Mix 60-second fast pace running with longer periods of running at a slower pace.
  • Use your environment to your advantage Adjust your pace to your environment and let it structure your sessions. This way, you become one with your surroundings and up the fun factor of your runs. For example, challenge yourself to run hard on the incline, slow down during the descent, then sprint to the nearest bench. Then keep running to the clump of trees in the distance, and so on.

Sample Fartlek Workouts

There’s no right or wrong way to run a fartlek so long as you keep running. But with a fartlek program optimized for your race goals, you can see results faster. Here are some examples of fartlek training exercises you may want to try:

1. Marathon-focused

This variation on the classic fartlek prepares you for the last 6 kilometers of a marathon. Or that challenging part of the race when prepared runners keep pushing while others fall behind. Here’s how to do it:

  1. After your warm-up, run 2.5 miles at your marathon pace.
  2. Then run 600 meters at a steady effort.
  3. Repeat each 5 times.

2. “Surroundings” fartlek

This is one of the most fun types of fartlek runs. More than good training, it can make you enjoy your surroundings more.

  1. Warm up with 10 minutes of jogging.
  2. Set your eyes on a tree, car, mailbox, or some other landmark in the distance. Run to it at a fast pace.
  3. After reaching the landmark, slow down to your normal running pace.
  4. Once you’ve recovered, pick another landmark, and run to it fast again.
  5. Repeat several times without exhausting yourself.

3. 5K/10K specific fartlek run

This fartlek workout prepares you for shorter races. It’s great for beginners and also boosts your body’s ability to use oxygen to power you up during races.

  1. Warm up at a jogging pace.
  2. Run at a fast but controlled pace that’s 10 seconds faster per mile than your 5K race pace.
  3. Recover with a 1-minute jog.
  4. Repeat 10 times.

4. Ladder workout

This type of fartlek is also known as a pyramid fartlek run. If you like giving structure to your runs, you’ll like it.

  1. Warm up with a 10-minute jog.
  2. Run 2 minutes at your 5K pace.
  3. Run 2 minutes at an easy pace.
  4. Run 3 minutes close to your 10K pace.
  5. Then, recover with 2 minutes of running at an easy pace.
  6. Run 4 minutes at your half-marathon race pace.
  7. Run easy for 2 minutes.
  8. Run 4 minutes at your half-marathon pace again.
  9. Run easy for 2 minutes.
  10.  Run 3 minutes at your 10K pace.
  11.  Recover with a 2-minute easy run.
  12.  Run 2 minutes faster than your 5K pace.
  13.  Lastly, cool down with a 10-minute jog.

5. Treadmill fartlek run

What about rainy, blisteringly hot, or freezing days? Those are perfect for a treadmill fartlek run.

  1. Warm up for 10 minutes at 7mph.
  2. Run 1 minute at 10mph.
  3. Without stopping, increase the incline to 6% and keep running for 30 seconds.
  4. Jog at 7mph for 3 minutes.
  5. Run for 2 minutes at 11mph.
  6. For one minute, shift to 9mph and up the incline to 7%.
  7. Slow down to 6mph for 3 minutes.
  8. Increase the incline to 7% for 2 minutes.
  9. Up the speed to 9.5mph and keep running for as long as you can maintain your form.
  10.  Cool down with a 5-minute slow jog.

How Frequently Should You Do Fartlek Running Sessions?

How many fartlek runs you do depends on your running goals and current fitness level. A personalized plan can help you strike a good balance between effort and recovery.

Start with at least one fartlek run every 2 weeks. If your current workout is already demanding, you can do a fartlek every 3 to 5 weeks.

If you really like fartlek, you can do it every week. But make sure to adjust your running plan accordingly. Doing fartlek on top of 2–3 weekly running sessions may be too much. It can increase your injury risk.

Take It to the Next Level

Fun, exciting, never boring, and effective, fartlek runs can transform your workouts.

Fartlek runs are beginner-friendly. They’re great training for long-distance running. Do them to boost your speed, endurance, anaerobic threshold, and mental strength. With fartlek in your workouts, reaching your race day goals will become easier.

So, how about some speed play next time you run?

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Written by

Chris Zibutis

Chris Zibutis is the Head Running Coach and founder of Joggo – that one person on earth who loves interval runs.  He holds a degree from Copenhagen Business School and is an avid runner – having participated in numerous marathons and triathlons, Chris brings substantial fitness and running experience to the Joggo team.