Yasso 800s

Hi all runners,  does or has anybody used 'yasso 800s' read a bit about them,  a straight forward interval session that can predict your marathon time.  Was wondering if they work,  and would they work for half marathon also?  I like the idea as its simple and sounds effective.  Would like some opinions on it before i begin my autumn half mara program.  Many thanks.


  • MinniMinni ✭✭✭
    I'm not sure how they would relate to a half. As far as the marathon's concerned it's not that simple. I was doing them around 3:15 in the Spring but couldn't run a 3:15 marathon! At the time I used them to gauge my improvement on intervals having not really done speed training before.
  • You're supposed to do 10 x 800's and take an average but as they're only supposed to work well into your marathon training program they're of little use to use before you start it.

     Bart Yasso is on this weeks Marathon Talk podcast and explains how he came to 'realise' them.

  • JoolskaJoolska ✭✭✭
    I think they're a bit of a gimmick and they don't hold true for me.  I'm the reverse of Minni, it would seem, in that my endurance is good but my speed sucks, so although my marathon pb is 3.03, I rarely hit 6m/m - 6.10m/m (which is what the Yassos would be) in training.  For your average amateur runner, the endurance work is much more important than the odd speed session and a flat-out half marathon is also a much better predictor of your marathon time than a ~5k pace speed session.
  • Joolska i'm the opposite to you i'm not bad at the speed (i enjoy these sessions) but my overall volume isn't what it should be which is prob why my half mara time isn;t as good as i want.  I can fire out several 800s in less than 3 mins each but my half is 1.33.10, think i need more mileage.  Which interval sessions are recommended for half and full marathons?
  • Yasso's seem a gimmick to me, but I haven't tried them, and probably never will.

    Wolfy - as far as HM sessions are concerned things like: 1 x 6 miles with 60s, 3 x 2 miles with 90s. Any 10k work helps: 8 x 1km with 90 or 4 x 2km with 2mins. But to be honest, it's all about milage. Sessions just add the cherry to the cake. The cake being your basic miliage. The former is useless without the latter.  Joolska being a good example, she rarely hits 6min/mile pace in training but has a very good marathon time. Probably she does a lot of easy running and has good miliage per week.

  • Wolfy - You can use the yasso 800's predict your marathon. With that time go to

    mcmillanrunning.com/mcmillanrunningcalculator.htm and see the half time.


  • I ran the 3.03 off a peak of 65mpw; probably averaged something in between 55 and 60mpw for the 12 weeks leading up to the taper. Lots of at or about 8m/m running and several half marathons at 3 hour marathon pace, IIRC. I made my biggest half-marathon improvement (from 1.33 to 1.27) when I first did regular 60+ mile weeks. Practically no speedwork and frequently plodding at 8.30m/m, but a mini-taper worked wonders!
  • Yasso 800s to predict your marathon?  So Bart found that his average for a few 800s predicted his marathon time.  Lucky him.

    I can't recall the number of footballers who found that tying their left lace before their right then won a match, so now they always tie left before right and each time it works they chalk another mark up for the process.

    The amount, quality and quantity, of training you do will predict your marathon time, or half marathon time, and then on the day your result will be different.  If it's close to something that you did in training then you might consider that the session that you did predicted your time, but really it'll be everything that you did.  You wouldn't train on only 800m intervals for a HM - if you did I can guarantee it wouldn't predict your time.  Once your conversion is good over all endurance distances then any session will be a reasonable predictor.  Train, and don't rely on one simple idea.  Intervals for half's and fulls?  Long ones.  Longer than 800m.

  • IMO it's pretty simple.  Yasso 800s are run at something like 5k pace.  Therefore they are a good predictor of 5k time.  Therefore predicting your marathon time from your Yassos is a bit like predicting your marathon time from your 5k time; better than pinning a tail in the donkey, but there are much better predictors out there.

    I think the only reason they've caught on is because the maths looks elegant.  image

  • Yassoo 800s are great interval training, but they aren't marathon predictors.

    The logic works the other way round - if you're after a 3 hour 20 minute marathon, you should be able to do 10x800 in 3 min 20 sec each off 400m jog recoveries.  If you can't do that, you probably don't have the leg speed (Note - there can be exceptions like Joolska!)

    I can probably do a set of 3:10 Yassos at present, but my marathon PB is 3:17 and right now I doubt if I could run 20 miles let alone 26.2...

    Hope this help.

  • My understanding about Yassoo 800s is a way to evaluate you fitness level. 

    Doing a Yasso 800s doesn't mean you can run a marathon. 

     A yasso 800s is an interval training of 7.5 miles. Any person that follow a 10K program can run a yasso 800s, but this person can not think, that he can run a marathon just because of the  Yasso 800s results.

     On the other hand, if someone follow a marathon program, 4 weeks before race he can run the yasso 800s to evalute his fitness level, and set up a goal for the marathon.

     Another thing is that yasso 800s, seems to be an empiric, maybe it has a statistic truth, but I have never seen any scientific study that could prove it.

  • Thankyou for all replies i have to agree it is an over simplified way of evaluating marathon fitness. 
  • The recovery on Yassos (the same as the rep time) is far too long in my opinion. You should be able to do 800m reps off 60 sec rest at around 5km pace no problem if you're in good shape.

    I agree with Joolska, miles are more important for marathon (and indeed the half).

    Sure I read on here once something to the effect that if you're in shape for a 3:00 hour marathon the requisite Yassos wouldn't be a problem, but being able to do Yassos at 3:00 pace doesn't necessarily work the other way.

  • Depends I guess, if you are more speed orientated then they arent good indicator. I ran 10 x 800 with 200m jog between (less than suggested recovery) and I was averaging 2min45sec, there is no way at present I can run 2:45 marathon, maybe just over 3 hours at present fitness. However there was a guy finishing behind me by 10 or so seconds and he posted a sub 3 hour marathon. Do the long runs as well as this interval session (plus other runs in a week) and they could be quite accurate. I'd sway if your averaging 2:40s you'd defo do a sub 3 hour marathon...

  • XX1XX1 ✭✭✭
    I thought the way Yasso 800s worked was that if you wanted to run a marathon in 3 hours and 45 minutes then you'd have to be able to run 10 x 800 at 3 minutes and 45 seconds, which is a bit different to running them and then predicting a marathon time based on some average.

    There are a whole bunch of ways to predict race times... You just need to find the one that works best for you.
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