Not all Fartleks are Created Equal
Fartlek based workouts are common place within our training, but recently I have been utilizing a slightly different approach under the term “Aerobic Fartlek” (or lighter Intensity fartlek) and figured it would be worthwhile to go into more detail on what this really means and why it may appear in your training plan. First off, it’s easiest if I define what a Fartlek is and then outline what a more traditional Fartlek is before I jump into my aerobic Fartlek meaning.
What is a Fartlek?
The term Fartlek comes from Sweden, meaning “Speed Play” or as it was originally referred to ““go-as-you-please” running. In its simplest form, it’s run hard for a bit until you feel tired, recover and repeat. It’s the opposite to the rigidity of track-based interval work. The play aspect of this is something I like to emphasize. Runners often prefer detailed prescription with set paces, times, durations, heart rates etc. and the fartlek concept flies in the face of that. This can be challenging for some to embrace, but when you do, it can be a really fun way to train. A Fartlek can help strip away expectations that may be weighing our training down and instead allow us to run more freely, perhaps with the joy that has been missing recently within the grind of training. It provides opportunity to detach the leash that binds us to electronic devices like our watches and phones, and instead invest time in listening to and understanding how our body feels and responds to exercise. Maybe we even take note of the world around us which typically passes us by during a workout.
The Loose Fartlek
If we are fully embracing the Fartlek spirit then we wouldn’t see any or minimal durations prescribed. The ultimate would be something like, go out and run very hard and include recoveries every now and again when you feel tired. Repeat. Minimal direction, just go out and play with that speed. If you are new to fartleks or used to having more structure, this can be hard and so my athletes might see something like 20min Fartlek with hard reps at 8-9/10 RPE with durations of intervals and rest dispersed as you please. This structure has boundaries, but ultimately gives the athlete ownership over the workout. I personally love having this an option within my own training. If I’m having a rough week, feeling under the weather, or feeling the grind of training, I’ll throw this option in to freshen things up. “But Coach, won’t this disrupt my training if I’m not specifically targeting a physiological system?” The physiological component is only a single part of the training equation and it’s important not to neglect other components too. Sometimes we need to step away from the physiology and the science and get to the fun because there’s psychological gains to be had through this.
The Traditional Fartlek
This approach is what athletes are most familiar with. This type of Fartlek might look something like 4-3-2-4-3-2min with 1min recoveries in-between or 2*(2-1-2-1-2-1)/1min//3min. Pre-set durations for intervals and recovery periods, but typically no pace expectations set. “Coach, how fast should I run them?” A common question, which is usually met with “as fast as you can for the whole workout.” “Thanks Coach 🙃).
As a coach you have hired there can be a perception that we should provide every single detail and structure possible for you to go out and execute a workout, but that perception is misguided. As coaches we are creating opportunities to learn about you as a runner and challenge you to develop various skill sets that will develop you as an athlete. I believe that development process is best achieved through collaboration rather than an unilateral directive approach. To put it fully into perspective, what are you going to do on race day if your watch dies unexpectantly or GPS goes way off and there’s no mile markers out? Fartleks are an opportunity to prepare for such an occasion, but the real gold is better understanding how your body feels during different intensities and are what points you close or past the edge so that you can refine it for next time. This is one way to develop your internal intensity radar and become more in tune with your body.
“But Coach, what does ‘as fast as you can really mean?” It sort of answers itself, but I understand its helpful to provide some supporting material around that response. In an ideal world we’d record the whole of this workout from start to finish (with the warm up and cool down recorded separately) to see what our are average pace was across the workout and the total distance covered. When repeating this fartlek in the future, we’d then try to improve on that average pace and distance covered. This places emphasis on the recovery intervals within the fartlek and not just the ‘hard’ reps. It encourages us to find balance, but also makes for a very challenging workout. Of course not every Fartlek needs to be run this way, but it is a common way and something I’ve explored before and have started leaning more into recently.
The "Aerobic" Fartlek
I took the long way to get here, but we got here! The term ‘aerobic’ can be quite confusing as even the faster fartleks can be aerobic too, but it’s meant to indicate that this is a fartlek that is lighter in nature and the is targeting a different physiological response.
You may see a familiar formats such as 6-5-4-3-2-1min/1min or 6-4-6-4-6-4min/1min but the intent of these workouts is to feel totally in control and could comfortably keep going if required to. We do not want to finish these fartleks totally gassed, or begging for mercy. We are operating well below our Anaerobic Threshold (LT2) for this. I will typically include a note to suggest an effort level (not pace) around 6/10 RPE to reinforce that lighter concept of the fartlek. If we run an ‘aerobic fartlek’ at paces similar to our 5k or 10k (maybe even the Half Marathon), then we likely haven’t quite grasped the concept behind the run.
What is the purpose of this "Lighter" Fartlek?
I typically prescribe these type of fartlek runs early on in a training cycle, during a base phase of training or when there’s a change in environment (hello summer 😎). I’ll even prescribe it during times when I sense an athlete is fatigued or showing signs of burn out and needs recovery but could benefit from some aerobic stimulus. When we are in these stages of a training cycle we can be distracted by our goal pace or overestimate where we believe our fitness is.
The speed play concept removes the expectation of pace. It encourages the athlete to go out and turn the legs over in a controlled way without forcing a pace or feeling like we need to ‘perform well’ or ask “did I hit my pace”. The focus is on building volume of aerobic stimulus without accumulating significant fatigue. We are just preparing the body for the next phase of training. At periods throughout the year, it allows us to self-regulate for daily variation (heat, sleep, life stress) in a way that a fixed pace doesn’t.
As a coach, I’m also uncertain where your fitness is at this stage and having you run a time trial wouldn’t be productive. This type of workout gives me valuable insight into both your physiological fitness and mindset. How ready are you to train again? Do you know how to control the intensity? Is the athlete self-aware of where their fitness is right now? Do they have the discipline to manage more complex workouts in the near future?
Conclusion
The name “fartlek” will probably always cause a little confusion, because the traditional version and the aerobic version look similar from the outside: varied pace, no fixed splits, run by feel. But the job each one is doing underneath that shared format is different. My hope is now that we have a better understanding of the different Fartlek approaches and the ‘why’ behind each of them so that we can go out and execute as intended.