I think I finally get this 80:20 training

I think I finally understand 80:20 training, and the benefits that you get. For the past 3 years, I have been reading about it, here, on Training Peaks and IMJ, and I have roughly based my training on this strategy, especially this year… but I didn’t quite get it, suddenly I had an epiphany, and it all makes sense:

After my recent event in St Polten, I have been training, but maintaining a relatively low intensity, however on the bike I have been feeling really good.

On Wednesday, I did a 34km commute PB, then went even fast on the (normally slower) return leg, but my HR was only 153, slightly above Z2.

On Saturday, I cycled my regular 80km club ride, and took 13 minutes off my PB, average speed was faster than St Polten, despite being on road bike, with 1200m climbing, again my HR was only 149 BPM, which is zone 2.

On Sunday, I cycled round the Zugersee lake, this is a 40km ride, with around 300m elevation, no significant hills, just rolling, it took me 59mins at an average speed of 40.6kph, once again my HR was only 155 BPM.

Finally, today I cycled up our local mountain, Rigi, this is a 12km, 1400m climb, I wasn’t chasing, or even watching my pace, so I was stunned when I got home to see that it took me 1h10m, over 4 minutes faster than my previous PB, My HR was 153 bpm

These rides were all at 260-275W, yet my HR was around top Z2 bottom Z3. None of these rides felt hard and my legs don’t appear to show any sign of fatigue. Compare this with a Hill climbing TT I did 3 weeks ago, 5.4km with 560m climbing, my AP was 311W and HR was 173bpm - which is above my LTR, and left me completely shattered after 24mins

What I think that 80:20 training has given me the ability to ride at a high power (265W) at a relatively low level of intensity, however, as soon as I go above that level, the intensity increases massively, for relatively little incremental benefit in speed

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What he said…

I’m getting similar results in running…
My bikes nowhere near those speeds or that power, but in principal I’m getting similar results

One hour bike today, 221W average off 147 bpm average that is a big improvement for me…

Another +1. Not getting anywhere your results on bike but haven’t done the same work you have over winter/ability, but am seeing my own gains.
Had the same epiphany last week running - no improvement in fast running, but 6 months of IM training has seen my 4:50/km run drop by 10-15bpm, and plodding it out on tired day. Time will tell if that translates to being able to hold for 42km but looks reassuring.

That’s better than I was at a year ago. I think that the gains have come pretty suddenly, maybe going into competition season has pushed things to the next level

My run has also improved, but where I am getting real gains is going into the run with much fresher legs

In a 70.3 I guess I am gaining 10 minutes on the bike, and 10 minutes on the run

No idea how I will go on a full IM, but suspect/hope for 30-40 minutes


I also think that lots of people on IMJ are doing it wrong. I get a feeling that they train slow rather than at a low intensity (not sure if that makes sense?) also my hard sessions are really hard, thank zwift for that, but also in club rides going all out on the big climbs.

Yep I did a pb swim and run recently … at 50…
The bike was 11 bpm less and my usual 2:32.
The last 5k was probably the fastest 3 miles I’ve ran off a treadmill for 6-7 years… so I possibly under cooked it…

More importantly I could have gone on, if it wasn’t for the huge blister that formed in my k Swiss” s that have never ever given me he slightest graze…!

All off the back of 80/20…

That tri Taren was on about it a bit ago and it just rang a bell in my head.

I just make sure 80% of my training is at 145 bpm or below… the 20 % is pretty flat out…

I’m hopeful for IMUK… it’s so slow that there’s no pressure to hit any time bound targets as I think the median average time will be even slower than Lanza if not Wales.

2020 should see me on a fast course somewhere …?

Hamburg’s won’t be long…!

A lot of people on IMJ are just looking at cut offs…
All credit to them, one guy who’s 18 stone + was going to defer on the last day, he’s still in, and I hope he has a great day more than anyone… apart from me…
Some real shifters on there too, it’s quite funny at times

(2 * 70.3 Time) + 1 hour
That’s conservative, but realistic and won’t end in disappointment

Interesting read. Interesting with Seiler and his 80:20 is that within his zonal system the 80 part does go above the Friel type zone 2 so allows a pyramidal intensity distribution rather than 80% @ <=zone 2 and 20% >= zone 4. Also, as Matt says LSD shouldn’t really be slow but steady, as so many coaches have been saying for decades you want to spend a lot of time around aerobic threshold.

yeah but lots of people over estimate their aerobic threshold. If you notice your breathing you are probably above it.


80% of max heart rate … no?

Absolutely, the ego needs to stay at home when you start training like that but the pace soons pick IME. Gordo Byrn wrote a lot on this.

Seen various formula, 2.1 x 70.3, 2x70.3 +1hr, 2x70.3 + 40mins… Gives me a time between 10:00 and 10:30

Will use 70.3 Elsinore as my benchmark as course is similar to Hamburg

Often when running I can be observed counting out loud to 20, this is not some special timing technique, it is checking that I am not pushing too hard


Definitely not! An easy rule of thumb is that if you can’t talk in long sentences without worrying you won’t get to the end of them then you are above aerobic threshold.

Thanks for the tip…
Possible that this could be the same ?

I’ve done a lot of running at 144 bpm strict and the first 90 mins or so seem pointless…

We live and learn

Yeah, it’s very much course dependent. My 70.3 going into Copenhagen last year was Mallorca, and that’s quite different with a pretty substantial climb and twisty descent. 4:56 there translated to 9:51, so less than 2x. I then went and did a 4:28 a few months afterwards (c2x+1hr) - but that course was WR fast, and the benefit from the freeway traffic on the bike was significant.

Ultimately though, any conversion comes down to how conditioned you are for the longer distance. I’m yet to get remotely close to a “reasonable conversion” of my HM times to full marathon

Hey, Umm I suppose it’s technically possible but unlikely. I hate getting too deep into physiology as my own belief is that as amateurs and within the vagaries of the human body we shouldn’t worry about too much precision, as it takes all the fun and a lot of the benefit out of it.

Basically you have a load of different energy systems in your body (fat burning, carb burning, aerobic, anaerobic etc.) and they are used in a different mix at different effort levels.

Aerobic threshold is where you get some contribution from anaerobic energy - i.e. some lactic acid production, as opposed to none at the lowest output levels. This might happen at around 130hr (if you have a max of 200 that would be 65% of max). This is when you notice gentle breathing when exercising.

Anaerobic threshold is when your lactate acid production (anaerobic energy production) is at full blast but your body can still remove it without further build up i.e. it hurts (potentially a lot) but the pain is steady. Above your anaerobic threshold your time is limited. This might be at 160bpm (which again at a max of 200hr is about 80%). This is when you are breathing really hard but it is still controlled.

Hope that might be of some help :slight_smile:

Thanks for the detailed reply, I knew some but not all of it.
I’ve seen 183 bpm this year, which is higher then I’ve seen for a bit.
140-144 puts me under 80% nearer 75.

I’ll experiment on a long one tomorrow, I really agree with the fun bit!

Interesting - my max is around 200 with resting down in the high 40s yet I can comfortably hold 165-170 which is higher than you would suggest. My low intensity runs I try stay sub 150. A tempo takes me to 175 and race paced for 5k 10k sees peaks over 190. This is all running, my cycling HR is much lower and legs are the limiting factor. I guess it’s individual but I’m learning RPE.