What is 'slow pace' 80/20 etc

I know there is a lot of discussion about this, and the whole 80/20 thing so apologies for another thread, but I’m digging into specific detail which I hope others may find useful. Bear with me.

I almost always train on my own, I use a mix of the usual stuff, RPE, HR, power on the bike etc.
I’ve had a paid coach for over 18months when I first started and he pretty much got me to the level I have been since, with a few peaks and troughs - he had a head start as I rowed for many years including using training zones etc. etc.

Now I’ve got a bit older I’m really having to think about my easy/hard training and recovery and balance. Bottom line, I don’t recover or handle overall training stress nearly as well as I did even just 3 years ago.

6 weeks ago I ran a 1.36 in a half, it may have been a smidge short but let’s say comfortably under 1.40. That’s my most recent real ‘data point’. I would hope(expect) to be able to run a 3.30 marathon tomorrow if asked. My ‘easy run’ pace would normally be about 5.30/5.40, 6 if I am feeling lazy, and if I was race fit I would hope it would be 5.15-5.20. This is also what I would aim for in an IM marathon (which I presume is significantly slower than standalone pace)

BUT - I have a sneaking suspicion by many metrics that pace may be wrong. My HR would be about 130 (that doesn’t help really but I probably have a broadly average HR profile, if a slightly low max) and I wouldn’t really notice any breathing.

SO - today I went for a long run with a friend (without looking at watches) and by many descriptive metrics we were doing a long easy run - i.e. having a conversation without having to snatch breaths or worry about breathing. avg pace 6.30 HR 116.

Any ideas what is right? I struggle to see how you reduce your marathon time (stand alone or IM bearing in mind IM marathon should be at easy pace) if it’s around the 4.50-5.15 mark by running at 6.30, and I’m sure my coach never gave me any long workouts that slow. But it seemed far more fitting of an easy run (not tired afterwards, no impact on recovery from previous sessions, being able to have a full conversation while doing it) than trying to do 5.30.

Similarly on the bike a true easy pace (no feeling of effort at all) is something pathetic like 2W/kg 140W as 175W does involve some feeling of pressure, but I struggle to see how that can help for a 190/200W IM

I’d love to nail down some paces for the next few months training so any input appreciated.

(hope it all makes sense)

You are roughly the same pace as me. I’ve had a 1.38 HM much earlier in the year and a 43.30 and 45.30 10kms. I’d be thrilled with a sub 3.50 marathon.

For me my hard/interval pace is 4.00-4.15 per km, depending how I’m feeling.

I use tempo pace for 8-10km runs at 4.50 -5.00

Easy runs up to 15km are approx 5.30 and anything longer than that I don’t go faster than 6.00/km usually approx 6.20.

Over the years I’ve learnt that a genuine long easy run is best done completely ignoring pace. I find it less and less relevant and time on feet much more important.

It’s a tough one, if you look at the Strava of good national standard marathon runners (say sub 2:20) an awful lot of their mileage is genuinely slow, like 7:30 to 8 min mile pace when their marathon race pace is sub 5:30. But then they do an awful lot of miles at this pace, far more than us punters are able to do. So your “80” pace is probably slower than you think, but you need to do a good lot of miles at it to get the benefits.

Also, I went to a talk by the Ultra runner and Pennine Way record holder (which has stood for 30 years!) Mike Hartley and he said a crucial part of his training was hard interval sessions, because to be able to cruise for many miles at a decent speed you need to be able to run short distances fast. Then again he did run 150 miles a week!

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Thanks for the input peeps.
I think this might be where the ‘struggle’ comes from. If I was running 20hours a week (or even 10!) then I’d think 6.30 would work, but not on 4-5 hours a week - but am happy to be told otherwise.


I’m experimenting with 80/20 running this winter. One of the on line calcs (? Runners world ) gave the following pace targets:

Vo2max 3.30 per km - for intervals up to 1km, I’m trying to do one session per week with a training buddy, up to 6km of running at this pace in total.

LT 3.55 per km, this is my tempo pace for runs of up to 10km once per week, or maybe slightly faster at a park run. Also for the last few km of a fast finish run at some point in the week. It’s also pretty much my target pace for a half marathon in Feb =1h22 which would be a PB if successful.

So thats maybe 16km of faster running, all the rest-maybe 80%- I’m trying to do slower than 4.45 per km and as slow as 5.30 sometimes.

I dunno if it is going to work. But I am finding much easier to run nearly every day at this pace. Previously I tried to do most of my runs at around 4.15-4.30 pace and often when a bit tired from work or whatever, I just thought “nah” and canned it. That’s not happened so far this year. And knowing that the bulk of my running is a lot slower than target race pace is really making me want to give priority to the hard 20% & nail those runs. So the concept is beginning to make sense to me. And this is on about 5-6 hours per week so similar situation to you tuckngo

Ps. Maybe other people are different, but i don’t find any kind of running easy - ever. It’s running!

Lying on a sun bed in Playa Chica, that’s easy :sunny::parasol_on_ground::tropical_drink::+1:


I think you nailed it.

It’s aerobic engine development, builds endurance and strength with lower injury risk.

The tempo and interval work push your aerobic and anaerobic limits, so that you can run faster with aforementioned engine on race day, but these sessions have higher (and cumulative) injury risk and do not develop endurance.

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Thanks everyone - some informative points being made - particularly about all running being hard :joy:

More seriously though - I think this is what confuses me - is 6.30 (in my case) really going to build anything?

yes… you don’t need to be busting your gut to build your aerobic system… its all about your energy systems, not muscular strength… and the mitochondria, vascular capacity etc, associated with that energy system are all improved at low effort levels (but you don’t neccessarily ‘feel’ it like you do muscular stress)… when you start to work harder, you start to develop your anerobic and muscular strength system as well, but not a great extra amount of the aerobic side. This is well documented by biologists and sport scientists. Its worth being clear that these aren’t discrete seperate ‘modes’, and as your effort levels increase, the aerobic system is supplementd by the anerobic system, not replaced.
(I get this from listening and discussing intently with, and reading the books of, my daughter who is a recent Loughborough biologist graduate from the exercise and sports science department)


I think you’d find useful to listen through a bunch of podcasts if you want to get to the bottom of it; Scientific Triathlon, TrainerRoad and less science more summary Coach Joe Beer SMARTcast

At the moment I think people either believe in one of two schools of thought, because it’s easier to think of it that way, but the reality is just balancing easy,aerobic,nose breathing exercise with a variety of intensities (dependant on your goal) to get the best blend for you (dependant on your age, fitness, nutrition and recovery, etc)

As said above, I would recommend you listen to the Joe Beer podcast as he is regularly answering the exact same question and is far better than me at explaining it! I am trying the 80 : 20 method or more like a 90:10 at the moment and I’ll see what happens next spring.

Same here. Time and again you here the phrase. “Make the slow slow “ easy to the point where you can’t believe it has any benefit. I followed MAF program last year and it’s very similar. You should be able to have a normal conversation and breathe through your nose.
Does it work? As far as I’m aware it’s proven beyond doubt. But you do need to follow it quite strictly.

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What about the “if you want to run 4 min/km you need to run at 4 min/km”?

I agree that lower speed helps, and greatly reduces damage, but I find it near impossible to adapt to higher speeds unless I train at higher speeds.

Where is anybody saying not to train at all 4min/km?

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I think you’d train 80% significantly slower that 4min/km, 10% at 4min/km and 10% faster than 4min/km.
That’s clearly approximate, but that’s the general idea. You spend very little time training at race pace.


I do 85% really really slow, 10% at just below race pace, and 5% at ‘make you feel like throwing up’ pace.


Not quite the same thing, but to counter @Chrace 's point, take my 10k yesterday as an example.

For the past 6+ weeks, all I’ve done is marathon pace work. A few have been commenting on my sessions, both here and on strava, but the fastest I have run in probably more than 2 months, is about 3:50/km pace within some over/under marathon pace long sessions. The only time I’ve run anything like 10k pace is as some 100m strides to end easy aerobic runs.

Yesterday, with no specific prep at all, I set a new pb and ran 3:35/km pace for 10k. I went through 5k in 17:38 which is only 16s off my 5k pb.

Its definitely counter intuitive, but pushing up from the bottom (eg building the base with lots of sub threshold mileage) definitely seems to translate to a faster threshold pace with no work at, or faster, than that pace whatsoever


I’m with Steve here. All my run training for past 6 months has been triathlon specific. Autumn interval sessions started again and I am amazed how fast I can run (not quite His pace though)

“In this research, he discovered that most endurance athletes spend the majority of their training time (~90%) at very low intensities (below the first lactate/ventilatory threshold) with most of the remainder of the training time spent at high intensities (above the second lactate/ventilatory threshold), with little time spent in between. This training intensity distribution has become popularised and known as ‘polarised training’.”