Definition of fartlek in English:

fartlek

noun

  • [mass noun] A system of training for distance runners in which the terrain and pace are continually varied.

    • ‘Also called fartlek training, intervals are used by competitive endurance athletes for improving speed and conditioning.’
    • ‘On a specific route, landmarks can be used to change speed and direction and drills, such as the crocodile, back to front and fartlek, thrown in to add variety.’
    • ‘The basics of fartlek is to vary your training routine, have fun and invent new things to do.’
    • ‘In phase three, formalize your fartlek training by replacing it with strict intervals.’
    • ‘This weekly program devotes four days to recovery training and two to aerobic and threshold training, via fartlek or ‘speed play’ exercise.’

Origin

1940s: from Swedish, from fart speed + lek play.

Pronunciation:

fartlek

/ˈfɑːtlɛk/