Fartlek Training for Runners: Build Speed and Endurance with Swedish Speed Play

Published: Cardio & Conditioning Guide

Tired of dreading structured track intervals but still want to build speed? What if there was a training method that delivers the physiological benefits of interval training without the mental grind of watching a stopwatch? Enter fartlek—Swedish for "speed play"—a flexible, enjoyable approach to speed work that's been transforming runners from beginners to elite athletes for nearly a century. Here's everything you need to know about this game-changing training method.

Why Fartlek Training Matters for Athletes

Whether you're training for a 5K, marathon, or just want to improve your running fitness, fartlek training offers unique advantages that complement traditional training methods:

• Race-specific preparation: Races rarely maintain constant pace—you navigate hills, respond to competitors' surges, and adjust to wind. Fartlek trains your body to handle these variable demands.
• Mental resilience: The freedom to adjust effort based on how you feel develops the self-awareness crucial for race-day pacing decisions.
• Multiple energy systems: Unlike steady-state running that primarily targets aerobic capacity, fartlek's varied intensity trains both aerobic and anaerobic systems in a single session.
• Sustainable motivation: The "play" aspect reduces training burnout and keeps speed work enjoyable year-round, crucial for long-term athletic development.

Understanding Fartlek Training

Fartlek is a Swedish training method whose name literally translates to "speed play." It combines continuous running with interval training in an unstructured, playful format. Unlike rigid interval workouts with precise work:rest ratios, fartlek is spontaneous—you vary your pace throughout the run based on how you feel, terrain, or arbitrary landmarks.

Developed by Swedish coach Gösta Holmér in the 1930s, fartlek training was created to make interval training more enjoyable and less monotonous. It bridges the gap between long, steady runs and structured speed work, offering the benefits of both while maintaining a sense of fun and freedom.

Key Characteristics of Fartlek

Continuous Movement

• No complete stops—keep moving throughout the session
• Easy pace between hard efforts (active recovery)
• Total duration typically 30-60 minutes
• Maintains elevated heart rate throughout

Variable Intensity

• Mix of easy, moderate, and hard efforts within one session
• Pace changes based on feel, not strict time intervals
• Can include surges, sustained tempo efforts, and recovery jogs
• Mimics the variable nature of sports and races

Unstructured Format

• No predetermined work:rest ratios (unlike "30 sec on, 90 sec off")
• Freedom to respond to how you feel during the run
• Can use landmarks: "sprint to that tree, recover to the stop sign"
• Allows for creativity and spontaneity

Terrain-Based

• Originally designed for trails and varied terrain
• Use hills, flats, and descents to vary intensity
• Natural environment enhances the "play" aspect
• Can be adapted to track, treadmill, or roads

Classic Fartlek Formats

True Fartlek (Unstructured)

Method: Run continuously for 30-60 minutes, varying pace spontaneously

• No predetermined structure or intervals
• Surge when you feel good, recover when needed
• Use landmarks: "Fast to that mailbox," "Hard up this hill"
• Example: 5 min warm-up jog → 40 min of playful speed variations → 5 min cool-down jog

Best for: Experienced runners who understand pacing, mental break from structured training

Structured Fartlek

Method: Predetermined intervals but with fartlek spirit (landmarks, feel-based intensity)

Best for: Beginners to fartlek, those who want some structure but more freedom than traditional intervals

Hill Fartlek

Method: Use hills as natural interval markers

• Run easy on flats and downhills
• Push hard on uphill sections
• Let terrain dictate interval duration
• Builds strength and power while improving cardiovascular fitness

Pyramid Fartlek

Method: Increase then decrease interval duration

Landmark Fartlek

Method: Use physical landmarks to define intervals

• "Sprint to that tree, jog to the next intersection"
• "Fast between telephone poles, easy for two poles"
• "Hard through the park, recover on the sidewalk"
• Perfect for outdoor running, makes training engaging

Benefits of Fartlek Training

Psychological Benefits

• More enjoyable: Feels like play, not rigid structure
• Mental break: Freedom from constantly checking watch or hitting precise splits
• Reduces monotony: Every fartlek session is different
• Lower pressure: No "failed" intervals—you just adjust effort as needed

Physiological Benefits

• VO2 max improvement: Hard efforts push aerobic capacity
• Lactate threshold: Sustained tempo sections improve threshold
• Multiple energy systems: Varied intensity trains different metabolic pathways
• Running economy: Pace changes improve neuromuscular efficiency

Race-Specific Preparation

• Variable pace practice: Races rarely maintain constant pace (hills, wind, surges)
• Surging ability: Practice accelerating when already fatigued
• Recovery on the move: Learn to recover while still running (crucial for racing)
• Tactical awareness: Develops instinct for when to push and when to ease

Versatility

• Works for beginners to elite runners
• Adaptable to any fitness level (adjust intensity and duration)
• Can be done anywhere: trails, roads, track, treadmill
• Suitable for all distances (5K to marathon training)

Lower Injury Risk vs Traditional Intervals

• No all-out sprints that strain muscles and tendons
• Continuous movement keeps muscles warm
• Flexibility to ease off if something feels wrong
• Natural pacing based on feel reduces overexertion

Fartlek vs Other Training Methods

Fartlek vs Traditional Intervals

Fartlek vs Tempo Runs

Fartlek vs Long Slow Distance (LSD)

Programming Fartlek into Your Training

For Beginners

For Intermediate Runners

For Advanced/Competitive Runners

Weekly Training Schedule Example

Sample Fartlek Workouts

Beginner Fartlek

Intermediate Fartlek

Advanced Trail Fartlek

Race-Specific Fartlek (10K Prep)

Tips for Effective Fartlek Training

1. Start Conservative

• First few hard efforts should feel controlled, not all-out
• You should finish feeling like you could do one more interval
• Better to end wanting more than completely destroyed

2. Use Perceived Effort, Not Pace

• Don't obsess over pace on GPS watch during fartlek
• Run by feel: hard = hard breathing, fast = comfortably hard
• Terrain and wind will affect pace—effort is what matters

3. Vary the Fartlek Format

• Don't do the same fartlek workout every week
• Rotate between short/fast, medium, and long/sustained efforts
• Mix structured and unstructured sessions

4. Choose Appropriate Terrain

• Trails and parks are ideal for unstructured fartlek
• Roads work fine for structured sessions
• Avoid busy intersections that force frequent stops

5. Stay Continuous

• Never stop completely during fartlek session
• Even between hard efforts, keep jogging slowly
• This maintains cardiovascular stimulus and mimics race conditions

Common Questions About Fartlek Training

How often should I do fartlek training?

For most runners, 1-2 fartlek sessions per week is ideal. Beginners should start with once weekly, while experienced runners can incorporate fartlek as one of 2-3 weekly speed sessions. Always allow at least one easy day between hard workouts. The key is balancing fartlek with other training methods—it shouldn't replace all your structured intervals or long runs, but rather complement them.

Is fartlek better than traditional interval training?

Neither is objectively "better"—they serve different purposes. Traditional intervals excel at race-specific pace work and measurable progression, while fartlek offers psychological benefits, training variety, and develops tactical racing skills. The ideal training program includes both. Use structured intervals when you need to practice specific paces for upcoming races, and fartlek for enjoyable speed work, mental breaks from structure, and building the ability to surge and recover during runs.

Can beginners do fartlek training?

Absolutely! Fartlek is actually an excellent introduction to speed work for beginners. Start with structured formats like 1 minute fast / 2 minutes easy for 6 repeats, keeping total session time to 20-30 minutes. The forgiving nature of fartlek—no strict paces to hit, ability to adjust effort mid-session—makes it less intimidating than track intervals. Just ensure you have a basic aerobic foundation (comfortably running 20-30 minutes continuously) before adding speed work of any kind.

How do I track fartlek training in FitnessRec?

FitnessRec offers multiple ways to log fartlek sessions. For structured fartlek, create a custom workout with your planned intervals (e.g., "3min hard / 3min easy × 4"). During your run, your GPS watch or phone tracks the session automatically. After syncing via HealthKit, Health Connect, or Garmin/Fitbit, FitnessRec displays your pace graph, heart rate zones, and total time. For unstructured fartlek, simply log it as a cardio session with notes about terrain, effort, and how you felt. You can review all sessions in your training calendar to track consistency and progress over time.

Getting Started with Fartlek

Step 1: Build base fitness with 3-4 weeks of easy running (if you're new to running)

Step 2: Choose a route with minimal stops (park loop, trail, quiet roads)

Step 3: Start with structured format: 5 min warm-up → 1 min fast / 2 min easy × 5 → 5 min cool-down

Step 4: Focus on effort, not pace—hard should be hard breathing, easy should be conversational

Step 5: Log session in FitnessRec with notes on how it felt

Step 6: Progress by gradually adding time, intensity, or moving to unstructured fartlek

Step 7: Experiment with different formats—find what you enjoy most

Fartlek training combines the physiological benefits of interval training with the psychological enjoyment of unstructured "speed play." It improves VO2 max, lactate threshold, and running economy while being more enjoyable and less mentally draining than rigid track intervals. Whether you're a beginner learning speed work, an intermediate runner seeking variety, or an advanced athlete wanting a mental break from structured training, fartlek has a place in your program. Use FitnessRec to plan, track, and analyze your fartlek sessions for continued progress and enjoyment in your running.