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Tuesday, October 6, 2009

YASSO 800s & half marathon predictions

I recently received a good question regarding using Yasso's 800s as a means by which one can figure half marathon shape using the formula. If you don't know about this workout, you are in for a treat. Bart Yasso, Runner's World figure, author & running guru extraordinaire & good friend, discovered that if you run 10X800m with a 400m jog recovery between each, your average time in minutes & seconds for the workout approximates your time capability, in hours & minutes, for the marathon - so if, for example, you run 3min & 55sec for your 800s, your marathon time could be predicted at 3hours & 55 minutes - weird huh? Well there's no physiological basis for this, it's just a quirk of statistics. Anyway, I use the workouts & suggest the process in my book, Run Workouts for Runners & Triathletes that came out earlier this year.

Check out this article on Bart & the workout:

Here's the question: "LOVE your Run workout book - have a question re Yasso - for the Half Marathon - in the taper week you have athletes doing 8x800 - I know the routine for a marathon pace prediction but how does Yasso's 800's predict for a Half Marathon? Divide by two and then take another say 5% off." GW

& here's my answer: Bobby McGee: "Yassos are a good workout & as you might have read from my stuff, or even Greg McMillan’s stuff, we feel they under read by about 5:00, i.e. 10X800m with 400m jog recovery in 3:00 with sufficient mileage (55/60+p/w) equals about a 3:05 marathon. Of course with what I see at altitude it gets a little vague; but again sufficient volume is the key. I set the 8X800m as a HM workout because it is a good solid rep workout, not as any kind of prediction workout, as Yassos aren’t physiologically quantifiably justified any way – they're just a very quirky, freaky coincidence really & well done for Bart to see it & create a legend!

If however you want to use the number as a bit of a cross reference, even if based on Bart’s fantastical fancy, I suggest extrapolating the 8 reps out to 10, (say your runner averaged 3mins) & then pop that on McMillan’s calculator & add 2:30 & you’ll have a fair reflection based on the Yasso theory, i.e. about a 1:27:50 half marathon. I think your way, minus a further 5% would possibly under read too much.

Hope this helps,

Bobby McGee

1 comment:

  1. Great article and interesting notes on under indexing by about 5 minutes. That is great first hand experience. We also wanted to thank you for the link to MadeToRun and for referencing us in your article as well.