fartlek/ˈfɑːtlɛk/EtymologyBorrowed from Swedish fartlek, from fart (“speed”) + lek (“child’s play”).nounAn athletic training technique, used especially in running, in which periods of intense effort alternate with periods of less strenuous effort in a continuous workout.“In an article in Athletics Journal, Paul A. Smith described fartlek as "a continuous overdistance run with numerous faster-paced interval runs interspersed, until the runner feels tired, but not exhausted." Smith claimed that because fartlek existed in the mind of the runner as a form of play, it deemphasized the feeling or perception of fatigue. […] In a typical fartlek workout, you pick some lan”