Fartlek what? A Fartlek run is a specific type of training run that is very popular and very beneficial to runners of all abilities. The easiest way to describe a Fartlek is to jog at a comfortable pace and every once in awhile, add a surge in speed for a short period of time. It could be a 15-30 second burst or up to a couple minutes at a higher speed. After your burst of speed, relax back into your comfortable jog/run pace. As I was doing my run tonight, it reminded me of the way my kindergarteners and 1st graders run in the gym. It is never an even pace no matter how many times I explain, beg, plead, etc.
If you watch them run, these students jog, sprint, jog, look around, sprint really fast, walk, jog a little, etc., repeat over and over. A first grader that does a 5 minute run in my gym probably hits about 7 different paces in that short period of time. This isn't exactly a perfect example of a Fartlek, but kind of.
The great thing about the concept of a Fartlek is that anyone of any level can do it. If you don't have the fitness for long stretches of speed, run fast to the next telephone pole, or the end of the block. If you are on a track, jog the corners and sprint the straight aways, or vice versa. A Fartlek run really can and should fit into anyone's training routine.
Good luck and enjoy!