Swedish exercise to evacuate area in an escape of wind?

Wikipedia Word definitions in Wikipedia
Fartlek , which means "speed play" in Swedish , is a training method that blends continuous training with interval training . Fartlek runs are a very simple form of a long distance run. Fartlek training “is simply defined as periods of fast running intermixed ...

WordNet Word definitions in WordNet
n. a method of athletic training (especially for runners) in which strenuous effort and normal effort alternate in a continuous exercise

Wiktionary Word definitions in Wiktionary
n. An athletic training technique, used especially in running, in which periods of intense effort alternate with periods of less strenuous effort in a continuous workout.

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1952, Swedish, from fart "speed" (cognate with Old Norse fara "to go, move;" see fare (v.)) + lek "play" (cognate with Old Norse leika "play;" see lark (v.)).