I have read JohnP (and others) say this many times:

There are two big mistakes that most amateur runners make. They go too hard on their easy days, and not hard enough on their hard days. This usually means they don't get as much out of their speedwork as they could, and they don't go easy enough to really get a good recovery.

Taking that into consideration, I am now doing some tests on 80/20 training. That is, running 80 per cent of the time on low intensity and 20 per cent training hard.

It seems to be a good, scientifically based ratio and want to give a good try.

However, I wonder how is this 20% calculated: does it cover all the kms you run the day that is hard or just the ones that are run fast?

That is, say I do a pyramidal fartlek consisting on:

  • 1' at 5K page, 1' rest (running slow)
  • 2' at 10K pace, 2' rest
  • 3' at HM pace, 3' rest
  • 2' at 10K pace, 2' rest
  • 1' at 5K page, 1' rest

What should I compute on the "20% bucket"? The 1' + 2' + 3' + 2' + 1' = 9' or also the other 9' where I rest?

1 Answer 1


I think that you're running into one of the limitations of an overly simplistic model like "80/20". Note that I'm not saying the idea behind it is bad, but the way it's being conveyed loses much of the nuance.

To speak to what I believe to be the spirit of the model, don't stress about the distance or time per se. Rather make 20% of your runs be runs that are hard. When you're done it's because you can't anymore. If you're doing a fartlek, either more speed work, faster speed work, or a higher percentage of it. The goal is to ask your body to do what it almost can't.

But on the other 80% of your runs, take it easy. No no, easier than that. It should not really feel like a workout, more a shakeout.

You didn't ask this, but I'm going to throw it in anyway. Keep a log of your runs & races. Check how you were doing before 80/20, a few months in, a year or two in,... Eventually you will likely plateau. At that point, find a new program. It's likely not better, but different. Three or four times now I've followed a training program, and it was great for a year or two, but then I plateaued. I switched to a new program and got the same effects. I've even cycled back to some and seen the same thing happen again. Listen to your body, see what works, periodically check that it continues to work, and above all, don't hurt yourself.

Good luck.

  • Excellent, I loved the part of But on the other 80% of your runs, take it easy. No no, easier than that. Agreed with the plateau concept. I have been following this and that training and observed this behaviour. By the way, what is your way to check improvement? VO2Max is the one I am following nowadays.
    – fedorqui
    Commented Mar 2, 2021 at 9:09

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