How Fartlek Training Makes You a Faster Runner

Most speed workouts assume you have access to a track. Fartlek training assumes the opposite. It was built for trails, roads, parks, and uneven terrain, by a coach who wanted his athletes training in the real conditions they would race in.

The method has a nearly 90-year track record. It scales from your first attempt at speedwork to the structured session an Australian Olympian used to prepare for world-class competition. And it requires nothing except the ground beneath your feet.

What Fartlek Training Is (and Where It Came From)

The word "fartlek" comes from Swedish: fart meaning speed, lek meaning play. Speed play. The name captures the method precisely.

Fartlek training was developed in the late 1930s by Swedish Olympian Gösta Holmér. His problem was specific: Sweden's cross-country teams had been beaten throughout the 1920s by Paavo Nurmi and the dominant Finnish team. Holmér needed a new approach. His solution was described as "innovative as any idea in athletics history".

The original workout was demanding. Holmér's fartlek totalled 12 kilometres, with up to 5,000 metres run at faster than race pace. It worked. Sweden's results improved, and the method spread to training programmes worldwide.

Why Fartlek Makes You Faster: The Physiology

Fartlek sits at the intersection of two training styles. It blends continuous training with interval training, combining the steady aerobic effort of a tempo run with the variable intensity of track repeats.

The result is a dual stress. The variable intensities and the continuous nature of the exercise stress both the aerobic and anaerobic systems.

Traditional fartlek training is associated with increasing VO2max during hard running segments, where the effort should be at an intensity close to VO2max. When properly applied, fartlek overloads one or all of the energy systems, providing ideal general conditioning while adding freedom and variety to workouts.

For runners chasing a faster 5K or building towards a half marathon, that dual adaptation in a single session is efficient.

Fartlek vs Intervals vs Tempo Runs

These three speed workouts get lumped together, but they work differently.

The critical distinction: fartlek involves alternating between fast and slow bouts while never stopping. Interval training lets you rest fully between efforts. Tempo runs involve running at a continuous pace rather than alternating between sprinting and jogging.

That continuous nature is what makes fartlek closer to race conditions. You never stop during a race either.

How to Do Fartlek Training: Beginner to Advanced

Before You Start

Build a base first. You should be able to jog comfortably for at least 20 to 30 minutes before adding fartlek sessions. If you are still working towards that, steady easy running is the priority.

Session Length

Twenty minutes is a good target for beginners, while more advanced runners often aim for an hour. Start shorter and extend as your fitness improves.

Frequency

Once or twice a week is a solid starting point. Fartlek is a speed session, so it needs recovery days around it, just like any other hard effort.

The Self-Selected Pace Principle

This is what separates fartlek from rigid interval prescriptions. Fartlek training involves variable pacing, allowing for the training pace to be self-selected as you progress through the workout. Some days you push harder. Some days you pull back. The method accommodates both, and can be individualised for various goals, ranging from weight loss to top-end speed.

Sample Beginner Session (20 Minutes)

1. 5-minute easy jog warm-up
2. 1 minute at a hard but sustainable effort
3. 2 minutes easy jog recovery
4. Repeat that cycle 4 times
5. 3-minute easy jog cool-down

Pick up the pace when you feel ready. Slow down when you need to. The structure is a guide, not a rule. That flexibility is the point.

Sample Intermediate Session (35 Minutes)

1. 5-minute easy jog warm-up
2. 2 minutes hard, 1 minute easy
3. 1 minute very hard, 2 minutes easy
4. 3 minutes hard, 1 minute easy
5. 30 seconds sprint, 1.5 minutes easy
6. Repeat the block once more
7. 5-minute easy jog cool-down

Vary the efforts. Use landmarks (a tree, a lamp post, a hill crest) to dictate when you push and when you recover.

The Mona Fartlek: Australia's Structured Version

For runners who want fartlek's benefits with more structure, the Mona Fartlek is the benchmark.

Named for Australian distance runner Steve Moneghetti, it was devised by Olympian Chris Wardlaw. The session is a precise 20-minute protocol that pairs alternating periods of effort and recovery:

• 2 x 90 seconds on, 90 seconds off
• 4 x 60 seconds on, 60 seconds off
• 4 x 30 seconds on, 30 seconds off
• 4 x 15 seconds on, 15 seconds off

The "on" segments are hard (close to race pace or faster). The "off" segments are easy jogging. Total session time: 20 minutes of structured work, plus warm-up and cool-down.

The Mona Fartlek bridges the gap between free-form speed play and prescribed interval training. The descending work periods force you to maintain intensity as fatigue builds, which is exactly what racing demands. It works on any surface, at any location, and scales with your fitness: the structure stays the same, only your pace changes.

Where to Do Fartlek (and Why Outdoor Terrain Is the Point)

Fartlek works on the street, on a track, on a treadmill, or on trails. You can use trees, rocks, or hills as landmarks to mark your speed changes.

But terrain variety is the method's original purpose. Holmér designed it for cross-country, not the oval. Running fartlek outdoors means your speed changes respond to the environment: surging up a hill, recovering on the flat, sprinting between two park benches. That unpredictability mirrors race conditions far better than metered 400-metre repeats ever can.

For Australian runners training through summer, outdoor fartlek sessions also mean extended UV exposure. Protecting your eyes during those sessions matters. A pair of sunglasses built for running should stay put through pace changes and not fog when you shift from hard efforts to recovery jogs.

Research has shown that enjoyment is a key factor in whether people commit to an exercise programme. Fartlek's flexibility and self-directed nature makes it easier to sustain than rigid track sessions, especially when you are doing it somewhere you actually want to run. Find a route with hills, flats, and a few good landmarks. The terrain does half the coaching for you.