Fartlek, tempo, intervals: What's the difference?

Q: Fartlek, tempo, intervals? What's the difference and which one should I incorporate into my training?

A: A fartlek (Swedish for "speed play") workout is an unstructured run of pickups, running at a faster effort for a period of time or between markers, followed by a recovery period of easy effort running.  A fartlek run can be as simple as picking up the pace in between a stop sign, traffic light, etc. or, for a bit more structure, running at a faster effort for a few seconds or minutes.  Fartlek runs are fun, can be done anywhere, and help improve your speed and endurance.

A tempo workout is done at a comfortably hard effort and is intended to increase your lactate threshold. By increasing your lactate threshold, you can run faster and farther with less fatigue.  A comfortably hard effort should feel controlled and near a 7 on a scale of 1-to-10.  You should be able to talk in short sentences but not paragraphs.  The key is running at or below your lactate threshold.  Run too fast or too slow and you'll miss out on the benefits of a tempo run.

An interval workout is a short, repeated bout of hard effort followed by a recovery period of very easy running.  During an interval run you should be getting close to the "no-talk" zone, where you can only say a few words.  The recovery period should be long enough so that your intervals remain consistent and controlled.  Interval runs improve running form and efficiency and increase VO2 max (maximum amount of oxygen your body can use during exercise).

While interval and fartlek runs are both of short duration, an interval run is done at a much harder effort.  A fartlek run can be done at various efforts or paces.

It's important to begin with a warm-up and end with a cool-down (a few minutes to a mile of slow, easy running will suffice) when doing a fartlek, tempo, or interval run.

All three types of runs should be incorporated into your training.  They improve speed by stressing different systems and build mental toughness that is necessary for racing.

Kristy Campbell is an RRCA-certified coach located in Conshohocken and founder of Run The Long Road Coaching.  She believes that success in running comes down to hard work, consistency, and determination.  In her spare time, she runs around after her daughter, Fiona. 

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