Fartlek

Fartlek is Swedish for "speed play" and describes an unstructured workout where you alternate between faster and easier running based on feel rather than precise intervals. It was developed by Swedish coach Gösta Holmér in the 1930s as a way to make speed training more intuitive and enjoyable.

Unlike formal interval training on a track, fartlek is typically done on roads, trails, or paths. You might surge to a lamp post, jog to the next intersection, then pick it up again until you reach a hill. The lack of structure is the point — it teaches you to run by feel and change gears without overthinking.

Fartlek is especially valuable for beginners transitioning from easy running to speed work. There's no pressure to hit exact splits, and you control the intensity moment to moment. For experienced runners, fartlek bridges the gap between base training and formal interval work, and it's a great way to add speed stimulus without the mental burden of a structured track session.

Use landmarks as targets: "I'll run hard to that tree, then easy to the bench"

Start with short surges (20–30 seconds) and long recoveries as you build fitness

Don't overthink it — the beauty of fartlek is that it's supposed to be playful

Try a group fartlek where runners take turns choosing when to surge