[Stovegeothnon]

Ha! It's a Swedish word and sounds so silly that we must use it as often as we can

It means:

An athletic training technique, used especially in running, in which periods of intense effort alternate with periods of less strenuous effort in a continuous workout.

Basically, you run at an easy pace. Then you pick a spot ahead, like a sign or post, and sprint as fast as you can. Then you run at an easy pace again. You keep doing this for a mile or 2 in the middle of the run. In a 3-mile run, I'd do this in the for the 2nd mile. Usually, I sprint to a telephone pole, run easy to next, sprint to the next, etc. It helps build speed - which I'm in dire need of