"Fartlek training" is an invigorating way to spruce up cardio days and speed up weight loss. This training method comes from Swedish Olympian and coach Gösta Holmér and appropriately translates ...

Fartlek training involves running at different speeds for intervals, but that’s kind of where the rules end. Much like HIIT, it’s up to you to decide how you break up your work/rest pattern.

Fartleks are an informal version of interval training. To start fartlek training, head outside, warm up for a few minutes at whatever activity you most enjoy — whether it’s walking ...