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Fartlek Training: Speed Workouts for Runners

Have you fartlekked recently?

I am not trying to be rude here... It's Swedish for speed play.

The principle is simple: warm up, then run faster for a while, slower for a while, and repeat as many times as you want. Then cool down. It mixes faster running and slower running without rigid structure.

I used to hate doing fartleks. I never did them.

I wanted structure in my runs. I didn't like just going out there and running by feel, deciding on the spot how fast to go and for how long. Because every fartlek workout can be different — there's no way to compare two sessions. And I really needed that comparison to track progress.

However, in the last few years I have mellowed a lot and I have lost a little bit of that competitive personality. Sure, I am still wanting to run quickly. But I am less "number-bound". And I learned that sometimes an unstructured session is exactly what you need.

Depending on your personality type you will think that is quite alright, or not good at all!

The playful nature makes it fun and helps you connect with your body. That's why fartlek workouts are brilliant for beginners wanting to try speed work — you can decide, based on how you feel, how much you'll push yourself.

If you start doing structured speed workouts from a running program you picked up somewhere and you are actually not really ready for it, you run the chance of getting yourself injured. With fartleks the risk is smaller.

Comparison Table: Fartlek vs. Other Speed Workouts

So how does fartlek compare to other speed work? Here's the breakdown:

Workout Type	Structure	Effort Level	Recovery	Best For
Fartlek	Flexible/unstructured	Varies (5K-10K pace)	Active (float pace)	Speed introduction, fun variation
Intervals	Fixed distances/times	Specific (3K-5K pace)	Complete rest or jog	VO2 max, speed development
Tempo Runs	Steady sustained effort	Threshold pace	None during effort	Lactate threshold, race pace
Track Repeats	Precise distances	Very specific paces	Timed recovery	Speed, race preparation
Hill Repeats	Uphill efforts	RPE-based	Downhill jog/walk	Power, strength, form

The beauty is you're not locked into one intensity. Some efforts might hit 90% of VO2 max, others 85%. This variation trains different energy systems within a single session. Your body learns to handle pace changes while your mind stays relaxed about hitting exact splits. For more structured approaches to speed training for runners, fartlek serves as a perfect bridge between easy running and formal interval running sessions.

Step-by-Step Beginner Fartlek Session

So, when you start out, simply do a good warm-up, then pick a landmark and run there at a higher speed.

Total time: 35-40 minutes

Warm-up (10-15 minutes):

• Start with 5 minutes easy jogging
• Add 4-5 dynamic movements (leg swings, high knees)
• Gradually increase pace to comfortable running

Main Set (15-20 minutes):

1. Pick a landmark 200-400m ahead (street light, mailbox, tree)
2. Run to it at 7/10 effort — you should be breathing harder but able to say a few words
3. Float for 1-2 minutes at 5/10 effort — this isn't a jog, keep moving
4. Repeat 6-8 times, varying your landmarks and efforts

Cool-down (10 minutes):

• Easy running back to comfortable pace
• Finish with light stretching

Pacing guidelines:

• Fast efforts: 30-45 seconds faster per mile than your easy pace
• Float pace: 15-20 seconds faster per mile than your easy pace
• If you can't talk at all during fast efforts, you're going too hard

Your first session might cover 3-4 miles total. That's perfect. Focus on the rhythm of fast-float-fast-float, not the distance.

How Fartlek Fits Into a Periodized Training Plan

Fartlek training integrates differently depending on your training phase within your overall running training program:

Base Building Phase (8-12 weeks):

• One fartlek per week maximum
• Keep efforts controlled (6-7/10)
• Focus on teaching your body to change pace smoothly
• Sessions: 15-20 minutes of quality

During this phase, fartlek complements your base running development perfectly, adding gentle speed elements without the intensity of formal intervals.

Build Phase (6-8 weeks):

• Fartlek becomes more structured
• Introduce named sessions like Mona or Moose fartlek
• Efforts can reach 8/10
• Sessions: 20-30 minutes of quality

Peak/Sharpening Phase (3-4 weeks):

• Short, sharp fartlek sessions
• Race-pace efforts mixed with faster surges
• Perfect for practicing race tactics
• Sessions: 15-25 minutes of quality

Recovery/Off-season:

• Unstructured, fun fartleks
• Go by feel entirely
• Great way to maintain fitness without pressure

The key is using fartlek as a bridge. Too easy for intervals? Try fartlek. Too structured for your current mindset? Fartlek's got you covered.

Scientific Benefits: VO2 Max, Lactate Threshold, Mental Toughness

Fartlek training hits multiple physiological systems simultaneously — that's what makes it so effective.

VO2 Max Development:
Your maximum oxygen uptake improves because you're pushing into that 5K-10K effort range repeatedly. The varied pace changes force your cardiovascular system to adapt quickly, increasing your ability to deliver oxygen to working muscles.

The beauty is you're not locked into one intensity. Some efforts might hit 90% of VO2 max, others 85%. This variation trains different energy systems within a single session.

Lactate Threshold Enhancement:
Those floating periods between fast efforts? They're not just recovery — they're threshold training in disguise. You're running at or slightly above your lactate threshold pace, teaching your body to clear lactate more efficiently.

You can improve running performance significantly just by getting better at the float portions of fartlek sessions. You learn to run comfortably hard while managing accumulating lactate.

Mental Toughness Building:
Here's where fartlek really shines. You're making pace decisions constantly throughout the session. Should I surge now? Can I hold this pace to the next tree? How hard should I go up this hill?

This decision-making under fatigue builds the exact mental skills you need for racing. You learn to read your body's signals and respond appropriately — faster when you feel good, easier when you need to recover.

Neuromuscular Coordination:
The constant pace changes improve your running economy. Your body learns to shift gears smoothly, recruiting different muscle fibers as needed. This translates directly to better race performance when you need to respond to moves or vary your pace tactically.

Sample 4-Week Fartlek Progression Plan

Here's how you can progress through their first month of fartlek training:

Week 1: Foundation

• Session: Landmark fartlek (described above)
• Quality time: 15 minutes
• Efforts: 6-7/10 intensity
• Recovery between sessions: 2-3 easy days

Week 2: Extension

• Session: 8-10 efforts of 45-90 seconds
• Quality time: 18 minutes
• Efforts: 6-7/10 intensity, slightly longer
• Float time: 60-90 seconds between efforts

Week 3: Intensity

• Session: Pyramid fartlek (1-2-3-2-1 minutes)
• Quality time: 20 minutes
• Efforts: 7-8/10 intensity
• Include one longer 3-minute effort

Week 4: Structure

• Session: Modified Mona fartlek
• 2 x 60s fast + 60s float
• 4 x 45s fast + 45s float
• 4 x 30s fast + 30s float
• Quality time: 22 minutes
• Efforts: 7-8/10 intensity

Progression markers:

• Week 1: Focus on completing the session comfortably
• Week 2: Maintain pace better during longer efforts
• Week 3: Handle the intensity without form breakdown
• Week 4: Float effectively (not jogging slowly)

Each week should feel challenging but achievable. If week 2 feels too hard, repeat week 1. There's no shame in building slowly.

Fartlek on Different Terrains

The terrain you choose completely changes the fartlek experience. Different surfaces work for different training goals:

Road Fartlek:

• Best for: Pace awareness and speed development
• Use landmarks like streetlights, intersections, or buildings
• Consistent surface lets you focus purely on effort and pace
• Perfect for beginners learning to judge effort levels
• Try: Urban exploration fartlek — use traffic lights as your intervals

Trail Fartlek:

• Best for: Strength building and mental toughness
• Hills naturally vary the intensity
• Softer surface reduces impact stress
• Forces you to run by effort, not pace
• Try: Hill surge fartlek — attack every uphill, float the flats and downs

Track Fartlek:

• Best for: Precision and speed work
• Use the straights and curves to structure efforts
• Easy to measure progress (count laps)
• Other runners provide natural competition
• Try: Straight-curve fartlek — fast on straights, float on curves

Beach/Sand Fartlek:

• Best for: Power development and injury prevention
• Sand provides resistance training
• Unstable surface improves proprioception
• Lower impact on joints
• Try: Wave chase fartlek — surge when waves crash, float during calm

Park/Grass Fartlek:

• Best for: Form development and fun
• Softer surface encourages longer strides
• Natural obstacles create variety
• Great for group training
• Try: Tree-to-tree fartlek with direction changes

The key is matching terrain to your current needs. Feeling beat up? Hit the trails. Need speed work? Stick to roads or track.

Tools and Apps for Structured Fartlek Sessions

While fartlek can be completely unstructured, sometimes you want a bit of guidance. Here are recommended tools:

Smartphone Apps:

• Runkeeper: Custom interval workouts with audio cues
• Strava: Segment hunting creates natural fartlek opportunities
• Nike Run Club: Guided speed runs with coaching
• Adidas Running: Interval training programs

Apps that give audio cues without requiring you to look at your wrist constantly work particularly well.

Low-Tech Options:

• Music playlists: Fast songs for efforts, slower for floats
• Podcasts: Change pace during different segments
• Running partner: Take turns calling out effort changes
• Heart rate monitor: Use HR zones instead of pace

Are you interested in zone-based training? This is covered thoroughly in heart rate monitor running programs.

Online Resources:

• Running forums often share creative fartlek sessions
• YouTube has guided fartlek workouts you can follow
• Training websites offer downloadable fartlek plans

Remember: the best tool is the one you'll actually use consistently. Don't let technology complicate what should be playful training.

Named Fartlek Workouts for Structure Lovers

Some of us need structure. Here are proven fartlek sessions with names and reputations:

Mona Fartlek (Steve Moneghetti):
Steve Moneghetti is a famous Australian marathon runner who won several big marathons and picked up medals in Commonwealth Games and World Championships. Mona had that same problem mentioned before: he needed structure. His workout is:

• 2 x 90 seconds fast + 90 seconds float
• 4 x 60 seconds fast + 60 seconds float
• 4 x 30 seconds fast + 30 seconds float
• 4 x 15 seconds fast + 15 seconds float

This is tough. The key skill is learning to "float" between intervals — not jogging slowly, but maintaining a solid rhythm. Progress is measured by total distance covered in the 20 minutes, i.e. the fast and the float parts together.

Moose Fartlek (Julian Spence):

• 5 sets of: 3 minutes at 10K-HM effort + 1 minute jog + 1 minute at 5K effort + 1 minute jog

That's 30 minutes of quality work. The contrast between the longer threshold efforts and shorter speed bursts is brilliant for race preparation, especially when training for a half marathon.

Portsea Fartlek:

• 3 x 5 minutes fast + 1 minute float
• 3 x 3 minutes fast + 1 minute float
• 4 x 1 minute fast + 30 seconds float

This is 36 minutes of quality — definitely advanced territory. It's a tough one that I have used as part of half marathon and marathon preparations. Start with longer floats and shorter fast segments if you're not ready for the full version.

Michigan Fartlek:

• 1-2-3-4-3-2-1 minute pyramid
• Equal recovery between each effort
• Perfect for building both speed and endurance

Kenyan Hills Fartlek:

• 2 minutes moderate uphill + 1 minute easy downhill
• Repeat 8-10 times
• Builds power and teaches efficient downhill running

Each of these has been tested by elite athletes. But don't let that intimidate you — adjust speed, modify the times and intensities to match your current fitness level.

Common Fartlek Mistakes and How to Fix Them

Common fartlek mistakes happen frequently. Here's how to avoid them:

Mistake #1: Running the "fast" parts too fast
You turn every effort into an all-out sprint, then struggle to maintain any quality for the float portions.

Fix: Use the talk test. During fast efforts, you should be able to say 3-4 words with some difficulty. If you can't speak at all, you're going too hard.

Mistake #2: Floating too slowly
The floats become slow jogs or walks, which defeats the purpose of maintaining an elevated heart rate throughout.

Fix: Float pace should be roughly your normal training pace — maybe slightly easier, but still purposeful running. You should feel like you're recovering without completely backing off.

Mistake #3: Making every session different
While variety is good, having zero consistency makes it impossible to track improvement.

Fix: Use a core session (like Mona fartlek) once every two weeks, then vary your other fartlek sessions. This gives you both structure and creativity.

Mistake #4: Skipping the warm-up
You jump straight into fast running without proper preparation.

Fix: Always start with 10-15 minutes of gradual warm-up. Your first fast effort should feel controlled and smooth, not like you're fighting stiff legs.

Mistake #5: Going by pace instead of effort
You get fixated on hitting certain splits rather than running by feel.

Fix: Cover your watch during fartlek sessions. Learn to judge effort by breathing, muscle tension, and overall sensation. Check your splits afterward for reference, not during.

Mistake #6: Doing fartlek too often
Because it feels less structured, you think you can do it more frequently than other speed work.

Fix: Treat fartlek like any quality session. Once or twice per week maximum, with easy days between hard efforts.

FAQ Section

Q: How fast should I run the "fast" parts of a fartlek?

Run by effort, not pace. A scale of 1-10 where your easy pace is about 4-5, and your fartlek efforts should be 7-8. You should be breathing harder but not gasping. If you can chat normally, go a bit faster. If you can't say anything, back off.

Q: How often can I do fartlek workouts?

Treat fartlek like any speed work — once or twice per week maximum. You need recovery days between quality sessions. A typical program includes one structured speed session (intervals or tempo) and one fartlek per week.

Q: Is fartlek better than regular interval training?

They serve different purposes. Fartlek is great for beginners, mental freshness, and learning to run by feel. Intervals are better for specific pace work and measurable progression. Both work well in balanced training programs.

Q: Can I do fartlek during marathon training?

Absolutely. Fartlek helps you practice surging and responding to moves during races. It also breaks up the monotony of long runs. Try adding 10-15 minutes of gentle fartlek in the middle of your long runs.

Q: What if I can't maintain the float pace between efforts?

That's normal when starting out. Your aerobic system is still developing. It's better to jog slowly and complete the session than to stop completely. Gradually work on making your recovery pace faster over several weeks.

Q: How do I know if I'm improving at fartlek?

For unstructured sessions, you'll notice running faster efforts feels easier. After your cool-down, complete some light running stretches to help with recovery and maintain flexibility for your next session.

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