The Joy of Speed Play
Fartlek training offers something rare in the structured world of running workouts: freedom. Born in Sweden in the 1930s, this training method has helped countless runners develop speed and endurance while actually enjoying the process. When track workouts feel monotonous and tempo runs feel restrictive, fartlek provides a refreshing alternative.
The word "fartlek" translates to "speed play" in Swedish, and that playful spirit is what makes it special. Instead of watching your GPS obsessively, you run by feel. Instead of counting laps, you surge to landmarks. This approach builds the same physiological adaptations as structured intervals while keeping running fun.
The Swedish Innovation
Coach Gösta Holmér developed fartlek in the 1930s to help Swedish cross-country runners. His athletes trained in the forests outside Stockholm, using natural terrain variations to dictate pace changes. This method helped Sweden dominate distance running in the 1940s.
What is Fartlek Training?
Fartlek is a form of continuous running that incorporates random bursts of faster running followed by recovery periods. Unlike structured intervals with set distances and recovery times, fartlek allows you to vary your pace based on how you feel, the terrain, or external markers like lampposts or trees.
Fartlek vs. Traditional Intervals
| Aspect | Fartlek | Track Intervals |
|---|---|---|
| Structure | Flexible, based on feel | Fixed distances and times |
| Recovery | Easy jogging (continuous) | Standing rest or jog |
| Pace | Varies by feel | Precise target paces |
| Location | Anywhere (trails, roads, parks) | Usually track |
| Mental Load | Low - intuitive running | Higher - pace monitoring |
| Best For | Building speed intuitively | Race-specific preparation |
The Key Principles
Continuous Movement
Unlike intervals with standing rest, fartlek maintains continuous movement. Recovery is easy jogging, not stopping. This keeps heart rate elevated and builds aerobic endurance.
Effort by Feel
Rather than chasing specific paces, you run by perceived effort. This develops body awareness and teaches you to self-regulate intensity - a crucial race skill.
Variable Intensity
Surges can range from tempo effort to near-sprint. This variability trains multiple energy systems in a single session and mimics race surges and terrain changes.
Terrain Responsive
Natural terrain guides pace changes. Push on uphills, surge on flats, recover on descents. This makes outdoor running engaging and builds strength.
Benefits of Fartlek Training
Physiological Benefits
- VO2max improvement - Variable intensities stress the aerobic system effectively
- Lactate threshold elevation - Extended time near threshold improves clearance
- Running economy - Pace changes improve neuromuscular efficiency
- Speed development - Short bursts recruit fast-twitch muscle fibers
Mental Benefits
- Reduced boredom: Variable pacing keeps the mind engaged
- Body awareness: Running by feel develops intuition for effort levels
- Race simulation: Handling surges and pace changes mirrors race demands
- Stress relief: The playful approach reduces workout anxiety
- Confidence building: Proves you can run fast without perfect conditions
Practical Benefits
- No track needed: Do it anywhere - trails, roads, parks, treadmill
- Time efficient: Quality speed work without extended warm-up/cool-down
- Adaptable: Adjust on the fly based on how you feel
- Weather flexible: Works in any conditions
- Social: Easy to do with running partners of varying speeds
Types of Fartlek Training
Unstructured Fartlek
The original Swedish approach. Run continuously, varying pace based on feel, terrain, or external markers. No predetermined structure - just run how your body wants to run, with periodic faster efforts.
Best for: Beginners, recovery weeks, mental freshness
Structured Fartlek
Predetermined surge and recovery durations (e.g., 3 minutes hard, 2 minutes easy). Provides more consistency for tracking progress while maintaining the continuous running format.
Best for: Race preparation, measurable progression
Ladder Fartlek
Progressive surges that increase then decrease in duration (e.g., 1-2-3-4-3-2-1 minutes). Combines various intensities in a structured progression.
Best for: Building sustained speed, variety
Mona Fartlek
Named after Australian coach Steve Moneghetti's workout: 2x90sec, 4x60sec, 4x30sec, 4x15sec with equal recovery. A classic structured session used by elite runners.
Best for: Multi-pace development, race sharpening
Terrain Fartlek
Let the landscape dictate your efforts. Push hard on every uphill, recover on downhills, surge on flat sections. Perfect for trail running.
Best for: Trail runners, hill strength, outdoor engagement
Sample Fartlek Workouts
Beginner: Introduction to Speed Play
Total time: 25-30 minutes
- 10 min easy warm-up jog
- 6-8 x (20-30 sec pickup / 60-90 sec easy jog)
- 5-10 min cool-down jog
Pickups should feel "comfortably hard" - you could talk in short sentences. No need to sprint.
Intermediate: Classic Fartlek
Total time: 40-45 minutes
- 10 min warm-up
- 3 min tempo effort / 2 min easy
- 2 min hard / 1 min easy
- 1 min very hard / 1 min easy
- Repeat this cycle 2-3 times
- 10 min cool-down
Advanced: Mona Fartlek
Total time: 50-55 minutes
- 15 min warm-up
- 2 x 90 seconds (90 sec recovery)
- 4 x 60 seconds (60 sec recovery)
- 4 x 30 seconds (30 sec recovery)
- 4 x 15 seconds (15 sec recovery)
- 10-15 min cool-down
Efforts get progressively faster as they get shorter. 90s at 10K effort, building to 15s at near-sprint.
Trail: Terrain-Based Fartlek
Total time: 45-60 minutes
- 10 min easy warm-up on flat terrain
- Push hard on every uphill (controlled effort, not all-out)
- Recover on downhills and flat sections
- On longer flats, add 30-60 sec surges
- 10 min easy cool-down
Landmark Fartlek
Total time: 35-45 minutes
- 10 min warm-up
- Surge to lampposts, mailboxes, or trees of your choosing
- Recover until you feel ready for the next surge
- Aim for 10-15 surges of varying lengths
- 10 min cool-down
The classic unstructured approach. Let curiosity and intuition guide you.
How to Structure Your Fartlek Sessions
Effort Level Guidelines
| Effort Type | RPE | Feel | Duration |
|---|---|---|---|
| Easy recovery | 3-4/10 | Conversational, relaxed | Equal to or greater than surge |
| Tempo surge | 6-7/10 | Comfortably hard, controlled | 2-5 minutes |
| Threshold surge | 7-8/10 | Challenging but sustainable | 1-3 minutes |
| VO2max surge | 8-9/10 | Hard, need recovery soon | 30 sec - 2 min |
| Sprint burst | 9-10/10 | Near maximal, explosive | 10-30 seconds |
The Golden Rule of Fartlek Recovery
Recovery should always be active jogging, not walking or standing. The goal is to maintain continuous movement while allowing your heart rate to drop. If you need to walk, your surges were too hard - dial it back next time.
Best Terrain for Fartlek
Trails & Parks
Natural terrain variation provides built-in pace changes. Soft surfaces reduce impact stress during hard efforts.
Best for: Unstructured fartlek, terrain-based sessions
Quiet Roads
Consistent surface for predictable footing. Use landmarks like lampposts for surge points.
Best for: Structured fartlek, landmark-based sessions
Grass Fields
Soft surface for leg-friendly speed work. Requires more effort, building strength.
Best for: Beginners, high-volume weeks, strength building
Treadmill
Control speed precisely with buttons. Good for bad weather or when you need structured paces.
Best for: Structured fartlek, weather backup
Progressing Your Fartlek Training
8-Week Fartlek Progression
Short surges (20-30 sec), long recoveries (90 sec+). Focus on finding comfortable hard effort.
Extend surges to 45-60 seconds. Reduce recovery ratio toward 1:1. Add 1-2 surges per session.
Include longer tempo surges (2-3 min). Mix effort levels within session. Try structured formats.
Full Mona fartlek or ladder sessions. Include all effort levels. Race-specific surge practice.
Common Fartlek Mistakes
Going Too Hard, Too Soon
Starting surges at sprint pace leaves nothing for later repetitions. Begin moderately and build intensity through the session.
Inadequate Recovery
Cutting recovery short turns fartlek into exhausting tempo runs. Ensure genuine easy jogging between surges.
Watching Pace Obsessively
Constantly checking your watch defeats the purpose. Fartlek is about feel. Check pace afterward if curious.
Making Every Surge the Same
Variety is the point. Mix short sprints with longer tempo surges. Different intensities train different systems.
Skipping Warm-Up
Even playful speed work requires warm muscles. Always include 10+ minutes of easy jogging before surges.
Frequently Asked Questions
What is fartlek training?
Fartlek is a Swedish word meaning "speed play." It's a form of interval training that alternates between faster and slower running, but unlike structured intervals, the pace changes and recovery periods are flexible and often based on feel rather than precise times or distances.
What's the difference between fartlek and interval training?
Traditional intervals have set distances, paces, and recovery times (e.g., 6x800m at 5K pace with 90 seconds rest). Fartlek is more flexible - you might surge to the next lamppost, run hard up a hill, or pick up the pace when you feel good. This freedom makes fartlek mentally refreshing while still building speed and endurance.
How often should I do fartlek workouts?
Most runners benefit from 1-2 fartlek sessions per week. It can replace one of your interval sessions or serve as a moderate-intensity day between hard workouts. Beginners should start with one session per week, while experienced runners can include fartlek as a secondary speed session.
Is fartlek good for beginners?
Yes, fartlek is excellent for beginners because the flexible structure allows you to push when you feel good and back off when you need to. There's no pressure to hit specific paces. Start with short surges (20-30 seconds) with longer recovery periods, and gradually increase intensity as fitness improves.
What pace should I run during fartlek surges?
Fartlek paces vary by purpose. For aerobic development, surge at tempo to 10K effort. For speed work, push to 5K or mile pace. The beauty of fartlek is running by feel - some surges might be controlled, others all-out. Recovery should be easy jogging, not complete rest.
Can I do fartlek on a treadmill?
Absolutely. Treadmill fartlek works well for structured sessions - change speed for predetermined intervals. You lose the spontaneity of outdoor fartlek, but gain precise pace control. Great option for bad weather or when you want measurable consistency.
Key Takeaways
- Fartlek means "speed play" - embrace the playful, flexible approach to speed work
- Run by feel, not pace - this builds body awareness and racing intuition
- Keep recovery active - easy jogging between surges, never walking
- Vary your intensities - mix short bursts with longer tempo surges
- Use terrain creatively - hills, trails, and landmarks make natural fartlek guides
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