Fartlek Workouts: The Free-Form Training Method That Plays with Speed

Introduction

Fartlek, a Swedish term meaning “speed play,” is a training method developed by Swedish coach Gösta Holmér in the 1930s. Unlike structured interval running, Fartlek is based on continuous running, with acceleration segments of varying intensity woven into the run, without fixed distances or rest periods—purely run by feel.

For Taiwanese runners, Fartlek’s biggest advantage lies in its adaptability to complex urban environments. Taipei’s Xinyi Road, Dadaocheng Riverside Park, or the country lanes of the Tanaka Marathon can all serve as Fartlek training grounds—no track required, and no precise GPS pacing needed.

Physiological Benefits of Fartlek

Fartlek is effective because it stimulates multiple energy systems in a single session:

• Acceleration segments (high intensity): stimulate the anaerobic system, lactate tolerance, and fast-twitch muscle fibers
• Easy jog recovery segments: strengthen the aerobic base and promote lactate clearance
• Natural speed variation: simulates the accelerations, decelerations, and pace changes of a race

Research shows that compared with steady-pace long runs, Fartlek more effectively improves a runner’s VO2max and running economy while reducing mental fatigue.

Four Types of Fartlek Workouts

Type 1: Time-Based Fartlek (recommended for beginners)

Type 2: Landmark-Based Fartlek (ideal for urban runners)

Use landmarks along the route to determine acceleration segments, best suited to Taiwan’s urban environment:

• See a traffic light → sprint to the next utility pole
• Crossing a bridge → accelerate the entire way
• Uphill section → push the intensity higher; downhill → easy recovery

Type 3: Structured Fartlek (intermediate to advanced)

Designed for race preparation, with clear pace targets while maintaining continuous running:

• 2 km warm-up
• 3 minutes @ half-marathon pace + 2 minutes easy running, repeated 5 times
• 1 minute @ 5K pace + 1 minute easy running, repeated 4 times
• 2 km cool-down

Type 4: Pyramid Fartlek (advanced)

Acceleration segments build up then taper down, challenging the aerobic threshold and speed endurance:
1 + 2 + 3 + 4 + 3 + 2 + 1 minutes (easy running between each segment = half the duration)

Intensity Control: Feel Matters More Than Numbers

The core philosophy of Fartlek is running by feel. Reference points for acceleration:

• Tempo run intensity (can speak full sentences, somewhat breathless): approximately 6–7 RPE
• Interval intensity (cannot complete sentences, very breathless): approximately 8–9 RPE
• Sprint intensity (completely unable to speak): 10 RPE

Your condition varies from day to day—on good days you can run faster and more aggressively; when fatigued, reduce the intensity and number of repetitions. This flexibility is Fartlek’s greatest distinction from fixed workouts.

Practical Tips

1. Schedule it once per week, replacing a fixed interval session, to let your body adapt to unpredictable speed changes
2. Practice near the Tanaka Marathon course: the natural undulating terrain of country roads is ideal for Fartlek, simulating race conditions
3. Don’t look at your pace: put down the watch and focus on bodily sensations and breathing—this is the essence of Fartlek
4. Run with friends: one person calls the acceleration, another leads, and take turns deciding the acceleration segments to make training more fun
5. How to log it: only record total distance, total time, and roughly how many acceleration sets you did—no need to track each set’s pace in detail

Conclusion

Fartlek is the freest, most instinct-driven method in running training. Between structured intervals and long runs, adding one Fartlek session per week will make running fun again—and your speed will quietly improve without you even noticing.

Related Reading

• Fartlek Training: The Free-Form Design of Unstructured Speed Training
• Modern Applications of Fartlek Training: Mixed Strategies of Structured and Unstructured Approaches
• Fartlek Training for Road Running: The Scientific Benefits of Unstructured Speed Play
• Road Running Speed Training: Differences and Applications of Tempo Run vs Intervals vs Fartlek