fart·​lek | \ ˈfärtˌlek\
plural -s

Definition of fartlek

: endurance training in which a runner alternates periods of sprinting with periods of jogging

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History and Etymology for fartlek

Swedish, from fart speed, pace (from Middle Low German vart journey, pace, alteration of Old Saxon fard; akin to Old English fierd, fyrd military expedition, campaign) + lek play, game, from Old Norse leikr

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