
1) Athletic training
Found on
https://www.crosswordclues.com/clue/fartlek

Fartlek, which means `speed play` in Swedish, is a training method that blends continuous training with interval training. The variable intensity and continuous nature of the exercise places stress on both the aerobic and anaerobic systems. It differs from traditional interval training in that it is unstructured; intensity and/or speed varies, a.....
Found on
http://en.wikipedia.org/wiki/Fartlek

(Swedish: `Speed Play`), approach to distance-running training involving variations of pace from walking to sprinting aimed at eliminating boredom ... [1 related articles]
Found on
http://www.britannica.com/eb/a-z/f/10

Swedish for 'speed play,' a type of loosely structured interval training for runners, cyclists, and in-line skaters. It combines high-intensity segments with your regular training pace in order to build strength and speed.
Found on
http://www.encyclo.co.uk/local/20944

Swedish word for speedplay; workout includes faster running mixed with slower running; adds variety to training and can be performed in any setting
Found on
http://www.howtobefit.com/glossary-of-running.htm
noun a method of athletic training (especially for runners) in which strenuous effort and normal effort alternate in a continuous exercise
Found on
https://www.encyclo.co.uk/local/20974

Swedish for "speed play;" variable pace running; a mixture of slow running, running at a moderate pace and short, fast bursts. Fartlek training is a "creative way" to increase speed and endurance.
Found on
https://www.encyclo.co.uk/local/21244
No exact match found.