Did Somebody Fartlek?
Leave it to those crazy Swedes to come up with a name like Fartlek, clearly not knowing what kind of fun will be made of it by thirteen-year-old boys ... and the adult writers of this website. Ahem ... anyway, fartlek s a form of conditioning that mainly stresses the aerobic energy system due to the continuous nature of the exercise.
The difference between this type of training and continuous training is that the intensity or speed of the exercise varies, meaning that aerobic and anaerobic systems can be put under stress. Most fartlek sessions last anywhere from 20 minutes to an hour and can torch a great deal of calories. Fartlek training is generally associated with running, but can include almost any kind of exercise.
Sessions should be at an intensity that causes the athlete to work at 60% to 80% of his or her maximum heart rate (estimated at 220 minus age), and then reduced greatly in intensity during a recovery period. More or less, fartlek is just an oddly-named version of high-intensity interval training (HIIT).
To incorporate the fartlek (he he ... ahem, sorry) system into an outdoor running workout, select an object you can see off in the distance (a tree, a parked car, etc.) and then run almost at full-speed until reaching it. Recover with rapid walking or jogging for three minutes and then select a new object to run to.
By the end of this workout, you'll almost certainly be pooped. Sorry...couldn't resist.