A fartlek run is a cardio workout that involves alternating between fast running and slower jogging in an unstructured format.

Many long-distance runners and running coaches are advocates of fartlek training because it helps boost speed and endurance and gets you “race ready.”

Beginners also find it useful and enjoyable as it improves cardiovascular fitness, makes running fun, and helps foster mental toughness. 

In this article, you’ll learn what fartlek training is, its benefits, how to structure fartlek runs, 5 sample fartlek running workouts, and more. 

What Are Fartlek Runs?

Fartlek is Swedish for “speed play.”

In the context of running, Fartlek is a form of interval training that involves varying between periods of fast running and easy jogging. Unlike traditional interval training, however, you spontaneously alternate between each pace.

Fartlek training is popular among runners of all experience levels because it offers more flexibility and variety than typical training methods, and it encourages runners to listen to their bodies and adjust their intensity accordingly. 

For example, unlike tempo runs, which typically involve maintaining a steady, challenging pace for a long duration, or high-intensity interval training, where intervals are tightly controlled, fartlek running workouts allow you to change your speed impulsively.

This variability helps enhance aerobic and anaerobic fitness, as it mimics the changing speeds encountered in real-world running scenarios, such as races. 

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Benefits of Fartlek Training

Training fartlek provides numerous benefits for both mental and physical health. Here are some key advantages of incorporating fartlek runs into your fitness routine:

1. Improved Cardiovascular Fitness, Speed, and Endurance

Fartlek running helps to improve cardiovascular fitness by challenging and strengthening your heart and lungs. The alternating periods of fast and slow running enhance VO2 max and improve speed and endurance.

2. Mental Stimulation

Fartlek running adds an element of excitement and mental stimulation to your training routine. The ability to vary your running pace and choose different landmarks or cues (e.g., a street sign, when the song you’re listening to ends, or when a hill evens out) for speed bursts keeps your mind engaged, making the workout more enjoyable and motivating.

3. Adaptability and Variety

One of the greatest benefits of fartlek runs is their adaptability and variety. You can customize your workouts based on your fitness level, preferences, and running environment. Whether on a treadmill, running track, or exploring nature trails, you can incorporate fartlek intervals into your run.

4. Race Readiness

Fartlek workouts are ideal for race preparation because they allow you to practice speed bursts like those needed to pass competitors or sprint to the finish, mirroring real race situations. It also improves physical endurance and teaches you to manage your energy effectively throughout a race, enhancing your pacing strategy.

5. Mental Toughness

The workout’s varied intensity levels challenge you to stay focused and adapt quickly, similar to conditions in a race. This approach helps you develop the mental strength needed to handle the pressures of competitive running, boosting your confidence and determination in both training and races.

Fartlek Interval Training Framework

While fartlek running may seem less structured than other training plans, it still follows a basic framework.

Here’s an example of how you can structure your fartlek interval training:

  • Warm-up: Begin your fartlek workout with a 5-to-10-minute warm-up of light jogging or brisk walking to prepare your muscles and joints for the upcoming intensity.
  • Speed Play: Choose a landmark or cue ahead, such as a tree, lamppost, or street sign, and increase your speed to a challenging pace until you reach the designated point. This should be a fast but sustainable effort that pushes your limits.
  • Recovery: After the sprinting interval, return to a comfortable jogging or walking pace as your recovery period. Take this time to catch your breath, lower your heart rate, and prepare for the next speed segment.
  • Repeat: Continue alternating between speed bursts and recovery periods throughout your run. Aim for 4-to-6 cycles, gradually increasing the intensity or duration as your fitness improves.
  • Cool-down: Finish your fartlek workout with a 5-to-10 minute cool-down of gentle jogging or walking to bring your heart rate and breathing back to normal gradually.

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5 Sample Fartlek Running Workouts

1. Urban Fartlek

Select a route with distinctive urban landmarks. Use these features to structure your intervals. Here’s how you might do it:

  • Warm up with 5-to-10 minutes of slow jogging
  • Choose two urban landmarks, such as street lights, road signs, or crosswalks, as your markers, then run at a fast pace between two of these landmarks.
  • Once you reach the second landmark, slow down to a jog until the next one.
  • Repeat for a total of 4-to-6 cycles

2. Hills Fartlek

Choose a hilly route. Increase your pace while running uphill and recover on the downhill sections. Here’s an example:

  • Warm up with 5-to-10 minutes of slow jogging.
  • Run uphill at a challenging pace..
  • Jog or walk downhill to recover.
  • Repeat for a total of 4-to-6 cycles.

3. Music Fartlek

Create a playlist with songs of varying tempos. Match your speed bursts to the faster songs and recover during the slower ones. Alternatively, build speed during every song’s chorus and run slower during each verse. These workouts add a fun and musical element to your fartlek training.

4. Nature Trail Fartlek

Select a nature trail with varied terrain for your fartlek workout. Here’s how to structure it:

  • Warm up with 5-to-10 minutes of slow jogging.
  • Identify two natural landmarks, like trees, rocks, or terrain changes, as your markers, then run at a fast pace between two of these landmarks.
  • Once you reach the second landmark, slow down to a jog until the next one.
  • Repeat for a total of 4-to-6 cycles.

5. Partner Fartlek

Pair up with a running buddy for a social and competitive fartlek workout. This workout encourages motivation and adds an element of unpredictability:

  • Warm up with 5-to-10 minutes of slow jogging with a running partner.
  • One runner chooses a landmark (like a tree or bench) and then sets the pace at which both must run to it.
  • After reaching the landmark, both slow down to a jog at a pace decided by the other partner.
  • Switch roles for the next interval, so the second runner chooses the landmark and sets the pace.
  • Repeat for a total of 4-to-6 cycles.