Strong fartlek

Fartlek is a mixture of aerobic (easier) and anaerobic (harder)  running without any set structure for when you decide to put in hard efforts. Likewise you can vary the exact intensity and length of faster running any way you want. Strong fartlek is similar to normal fartlek, except that the purpose is to get a harder workout rather than a relaxing run.


  1. Warm-up 10 – 15 minutes
  2. Do 3-4 easy 60-70m stride-outs (10 second bursts) with full running recovery (about 3 times the stride time)
  3. Run a series of hard efforts of 30 seconds to 10 minute duration over undulating terrain with a running recovery equal to or longer than the time spend running hard. Read the description of our “sausage session” below for the best idea on how to do this.
  4. Cool-down 10 – 15 minutes

Important points: 

  • Run as hard as you like, but never strain, even in a strong fartlek, intensity should never be higher than 5k race intensity. Hold back at any sign of heavy fatigue.
  • The suggested pace given on the programme is the average pace. You should speed up and slow down according to how you feel, not by any set pace; because of the recovery runs, overall pace only comes out slightly faster than a medium long run
  • Like strides, this is a great way to stretch out during base training without resorting to traditional stretching (but remember – in our coaching model – you NEVER stretch!)

Rate of Perceived Effort: 


Experienced competitors/elites: 

While “play” may seem inappropriate to some serious competitors, Fartlek may be one of the most important workouts to maintain at all levels of competition to never lose the ability to simply improvise and running by feel. Elite athletes will use longer fartleks and perhaps harder terrain for their fartlek workouts but the principle remains the same.

Stronger fartleks in particular develop your ability to reuse “lactate” as a fuel, a metabolic adaptation that has proven extremely importance for high performance in long distance events. So strong fartleks can make a world of difference for runners of all levels. They are not the poor cousin of intervals!


  • Stamina
  • Leg Speed
  • Fun
  • Running by feel
  • Changing paces
  • Not relying on the clock
  • Tactical abilities
  • Cross-country running

 Biggest mistakes:

  • Trying to 0ver-quantify the run and making this speedwork rather than speedplay.
  • Repeatedly sustaining your fast portions too long and entering into oxygen debt and a fatigued state that you cannot quickly recover from.
  • Running to failure. We’re trying to get you used to running strongly, not blowing up!


Mixed and varied terrain (grass, trail, dirt-path) over an undulating course is ideal for this workout as it naturally helps you move out of your set rhythm. You can use the uphills and downhills for your hard efforts (working hard into the hills, striding fast down the descents and so on).

Specific formats

Sausage sessions:  This simple workout is one of the most powerful sessions you can do as a fartlek. It’s mildly structured but encourages run by feel and should be your default option:
  • Look at the duration of your strong fartlek – about 30% of the time should be spend on faster running
  • Create random blocks of faster work from 30 seconds to 5 minutes. Deduct 30 minutes for warm-up and cooldown (including strides) and then set aside one third of the remaining time for faster running
  • Example: You have 72 minutes strong fartlek to do. 30 minutes is warm-up and cooldown leaving 42 minutes for faster work. One third of this will be faster work (1/3 x 42 minutes = 14 minutes)
  • Now distribute your harder minutes into “sausages” of different sizes. Example: 14 minutes divided as (2-3-4-3-2 minutes), so you run 2 minutes hard, 4 minutes easy, 3 minutes hard, 6 minutes easy, and so on.
  • At the end of the fartlek do your cool-down
If you are running with a group, a number of rules apply that you can read about here. Make your paces natural and varied. Most of the harder intensities should be half-marathon to 5k race intensity. The longer the repetition the slower the pace.
OMNIUM: The Omnium fartlek can only be done as a group but it uses the formats from track cycling as a “speed game”. Read more about them here and join our Old School Training groups for a taste.


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