When it comes to boosting endurance and speed, many runners think of intervals or steady‑state runs. However, there is a playful and effective method that can transform your training: the Fartlek. The Swedish term translates as “speed play” and involves alternating rhythms within the same session, combining fast sections and recovery jogs without stopping.
What is Fartlek training?
Fartlek originated in Sweden in the 1930s thanks to coach Gösta Holmer, who was looking for a way to improve his athletes’ physical fitness. Its idea is simple: by varying the intensity and terrain during a continuous run, both the aerobic and anaerobic systems are stimulated. Unlike traditional intervals, there are no rigid work/rest schemes; you play with speed and perceived effort.
This flexibility makes Fartlek suitable for almost every runner. You can practise it in the park, on a trail or even on a treadmill. The key is to listen to your body and let the pace change naturally.
Benefits of Fartlek for runners
Regular Fartlek sessions provide numerous benefits that go beyond simply breaking the monotony of your runs. Some highlights include:
- Improves both aerobic and anaerobic capacity: alternating fast and moderate segments challenges your heart and muscles in different ways, improving your overall fitness.
- Increases endurance and running economy: by practising pace changes, you prepare for the surges and slowdowns of real races, which helps you maintain form when you get tired.
- Burns more calories: the variety of intensities boosts your metabolism and calorie expenditure, ideal if you are looking to manage weight.
- Develops mental strength and awareness: Fartlek helps you better understand your perceived exertion and how your body responds to different efforts.
- Prepares you for varied terrain: Fartlek can be done on trails, hills or roads, so you learn to adapt your pace to changes in surface and elevation.
How to do a Fartlek workout
To get the most out of a Fartlek session, follow these steps:
- Warm up well. Spend 10–15 minutes jogging easily and doing dynamic movements to prepare your muscles.
- Choose a work/rest structure. For beginners, start with 1 minute at a comfortably hard pace followed by 2 minutes of easy running; repeat 5–6 times. Intermediate runners can try equal work/rest ratios (e.g., 2 min fast / 2 min easy) and advanced runners can include longer hard segments or hill surges.
- Use natural markers. You don’t need a stopwatch: use trees, lampposts or trail segments to dictate when you speed up or slow down. Vary the terrain to challenge your body.
- Listen to your body. Fartlek relies on perceived exertion. Push yourself during the fast sections, but make sure you can recover during the easy parts. Avoid going over 90 % of your maximum heart rate.
- Cool down. End with 10 minutes of easy jogging or walking and some gentle stretching to facilitate recovery.
Variations and levels of Fartlek
One of the strengths of Fartlek is its versatility. You can adapt it to your level and goals. Here are some ideas:
- Beginner Fartlek: alternate between 1 minute fast and 2 minutes easy jog, for a total of 20–25 minutes. Focus on running by feel rather than pace.
- Intermediate Fartlek: perform 6–8 intervals of 2 minutes fast with 2 minutes recovery. You can include short uphill surges or run on varied terrain to simulate race conditions.
- Advanced Fartlek: try Swedish Fartlek (time‑based) with longer fast segments (3–5 minutes) and equal recovery, or Polish Fartlek (distance‑based) where you sprint between landmarks and use the terrain to dictate intensity. Incorporate race‑pace efforts or threshold segments to simulate competition.
- Trail or cross‑country Fartlek: choose a hilly route and surge on the climbs and flats while recovering on the descents. This improves your strength and technical skills.
- Off‑road or track Fartlek: on the track, alternate fast straights and easy bends; on the treadmill or bike, play with speed and incline to maintain variety.
Precautions and recommendations
Although Fartlek is enjoyable, it is still a demanding workout. Keep these tips in mind to stay healthy and get the most benefit:
- Don’t start Fartlek if you are a complete beginner. Build a base of consistent running for a few weeks first.
- Schedule Fartlek sessions once or twice a week and avoid doing them on consecutive days. Combine them with easy runs, long runs and strength training. For guidance on strength sessions, see our article on strength training for runners.
- Pay attention to recovery. Include at least one rest or cross‑training day after a hard Fartlek. Short strength workouts or mobility sessions can help you absorb the training.
- Use Fartlek to work on your lactate threshold by including 5‑minute blocks at a “comfortably hard” pace with 2 minutes easy. Learn more about the lactate threshold and how to train it.
- Enjoy the playfulness. Don’t get obsessed with exact splits; the goal is to develop your awareness and ability to adapt. On some days you’ll feel strong and on others you’ll need longer recovery—adjust accordingly.
By incorporating Fartlek into your training, you’ll not only improve your performance but also break the monotony of always running at the same pace. And if you want to track your workouts and connect with other runners, don’t forget to download the SnapRace app, where you can record your sessions and compete in virtual challenges.