Langfartlek

Langfartlek is a form of fartlek training that emphasizes longer running intervals. The term combines the Swedish words lang, meaning long, and fartlek, or “speed play.” Fartlek originated in Sweden in the early 20th century as a flexible approach to endurance work, and langfartlek represents a variation that stresses lengthier hard efforts within the session.

Typical langfartlek sessions alternate extended hard efforts with periods of recovery. Hard segments often last about 3 to 6 minutes at a tempo or near-threshold pace, followed by easy running or walking for 2 to 4 minutes. A complete workout, including warm-up and cool-down, usually runs 30 to 60 minutes.

The goal is to improve aerobic capacity and lactate tolerance, while building pace control and mental resilience over sustained efforts. Langfartlek can be adapted for different race distances, from 5K to half marathon, by adjusting interval length and intensity.

Implementation considerations include a thorough warm-up, progressive progression, and close attention to effort rather than speed on a given clock. It is generally more advanced than easy runs and may not be appropriate for beginners without coaching. Coaches often integrate langfartlek within a broader training plan to balance volume and recovery.

Relation to other methods: langfartlek sits between traditional fartlek, which features more variable intervals, and tempo runs, which are paced more steadily. Unlike fixed interval workouts with identical reps, langfartlek preserves flexibility in pace and recoveries while keeping long hard portions.