Fartlek, or “Speed Play,” Workouts
Fartlek, a Swedish word meaning “speed play,” is an unstructured type of speed work. The central purpose of fartlek runs is to train you for the anaerobic demands that more structured speed workouts and racing provide. Whereas more structured speed workouts, generally done on a track or an accurately measured course, encompass specified periods and distances of fast-paced running followed by recovery periods, the fartlek workout is quite different. You can run a fartlek workout at a fast pace in varying distances and durations.
Fartlek Running Guidelines
Even though it is considered an unstructured workout, there are basic guidelines for fartlek running. Begin your workout with a minimum of 1–1½ miles of easy running (or a minimum of 12 minutes). End with a 1-mile cool-down, throw in speed bursts of varying times and distances, and then follow each with a recovery jog.
The idea here is to practice running at a brisk effort (generally faster than your present 5K race pace), employing good running form and training your body to run anaerobically (meaning, without oxygen). Push yourself until your breathing becomes labored and your pace begins to drop off.
Just as you can run fartlek workouts in a variety of ways, you can perform them on various terrains, including on roads and trails. Before doing fartleks on hilly courses, however, it's best to accustom yourself to these workouts by running them on flat ground.
Planning a Fartlek Workout
So as not to overdo exercise and risk incurring an overuse injury, you should develop a specific plan for incorporating fartlek workouts into your training program. The first week the novice might aim for 4 minutes of total fast-paced running (for example, 30 seconds + 30 seconds + 30 seconds + 45 seconds + 45 seconds + 30 seconds + 30 seconds), adding 2 minutes of fast effort for each of the next three weeks. By having a specific plan ahead of time for enduring a cumulation of fast periods of running, you are less likely to risk injury by overdoing your workout.