The best approach to successfully achieving the spirit of fartleks

One of the most common questions we get from runners is how to run a fartlek workout. This is not surprising given that ambiguity and uncertainty have surrounded fartleks since their birth in Sweden in the 1930s. 

Our endeavor here will be to make abundantly clear how to run a fartlek workout successfully. To accomplish this, we will need to separate fartleks from other workout types as well as define clearly the purpose and spirit of the workout.

Delineating Common Workout Types

It might be said that there are really only two types of workouts at a fundamental level. Nuances aside, there are workouts that involve sustained running at a given pace, and there are workouts that involve some kind of change of pace or intervals of varying efforts. This being true, fartleks fall under the category of interval types of workouts.

More accurately, though, fartlek and interval are somewhat interchangeable terms. A fartlek workout is really just any combination of faster and slower running over a given duration. What makes it different from other interval workouts has more to do with purpose than form. 

Hearkening back to its origin, a fartlek is a playtime run (recall the translation of the word fartlek: “speed play”). To apply that properly, a runner must then use a fartlek workout differently than other intervals. Primarily, a runner must seek to engage a spectrum of efforts within a single workout along with easy running rest periods.

Additionally, at its core, a fartlek ought to differ from other workouts by being more precisely attuned to each athlete, and not merely to each athlete but even more to each athlete in each instance. One might therefore note that the fartlek workout is the runner’s tool to getting exactly what is needed in the moment of needing it.

Achieving the Spirit of the Fartlek Workout

Understanding that fartleks are both highly variable and differentiated, the aforementioned ambiguity and uncertainty makes perfect sense. Or maybe makes no sense at all. 

This is also why when seeking to run a fartlek, the question “But what exactly should I do?” is actually not very easy to answer. It’s also simply bad practice to try to answer it. (Which is why, for those of you whom we have coached, we are unapologetic in providing an unsatisfactory answer! But fear not and read on…)

First, the answer has to begin with the purpose and spirit of how to run a fartlek workout. The format in general terms is playing with speed across various efforts and paces, so the central purpose, therefore, is neuromuscular. Additionally, the goal of the workout is to provide the stimulation needed at that moment for that runner. Therefore, the spirit of the workout is to respond to the body’s needs both in terms of needs identified in recent training and needs manifesting as the workout unfolds.

This is incredibly challenging!

We are suggesting that in order to achieve the purpose and spirit of the workout, we need to be able to make in-workout decisions and adjustments without the input from a coach. The best coaching during a fartlek looks like this: “How are you feeling? Does it feel better to go faster or slow it down a little? Do you need to jog longer between pace changes? Do you want to try throwing in something different?”

Coaching someone through a fartlek requires knowing realtime reactions to questions like these. That’s not especially practical, though.

With this in mind, we really need an aid to achieving the intuitive goal without so much thinking.

A Framework for Executing an Effective Fartlek Workout

Let’s build a simple yet highly effective framework. With this in mind, we should be able to successfully achieve the goal very nearly every time we run a fartlek. The framework involves making 3 decisions on repeat in response to two simple physiological cues.

Decision 1: Should I pick it up now?

CUE: Am I feeling fresh enough to go fast?

As you are jogging (be it the warmup before the workout begins or a rest jog between faster sections), once you begin to feel fully recovered and comfortable, your body should be ready for another pace change. All you need to determine here is whether it’s time to get up and go.

Decision 2: How fast should I go?

Once you start accelerating (or perhaps just before), determine how fast you want to go. This is not complicated because the intent is variety. Whatever you did most recently, do something a little different. This can range from strong steady effort running up to and including short wind sprints (we call them leg speed  or running form strides).

Decision 3: Should I slow down now?

CUE: Are my legs starting to fatigue at this current effort?

As you push at the increased effort, monitor how you are feeling. Naturally, if you decided in #2 to go substantially faster, you are going to fatigue sooner. The key is slowing down before you cannot handle the pace any more.

Then repeat!

A fartlek can occupy a total duration of a wide spectrum, depending on the nature of the need (though we do not recommend doing fartleks for longer than 60 minutes total, including the jogging rest between). As you execute the workout, simply focus on how you are feeling, interspersing lots of variety along with plenty of easy jogging between faster efforts. 

Why This is Helpful

Knowing now how to effectively implement fartleks, we ought to reflect a moment on why this type of workout offers value to our training. In a word, variety. 

Fartleks are the Swiss Army Knife workout (yes, yes – I know it’s Swedish). They provide the opportunity to fill gaps in many ways because by their very nature, they can be whatever we want or need them to be in a given moment. For example, during such periods as general base training or conditioning work, fartleks provide a chance for some light and quick sessions without excessively taxing the energy system like hard interval workouts are prone to do. Additionally, during a more intense race-specific coordination period, fartleks are a great chance to keep in touch with training elements that might not be as present.

This is why fartleks are neuromuscular in nature and also why variety as well as substantial jogging periods are essential.

Now, don’t just take our word for it. Give that framework a try on your next fartlek session, then let us know how it went!