Yasso 800s seemed all the rage when I trained for my first marathon over a decade ago. The idea behind Yasso 800 is simple: run a workout of 10 x 800m with equal jogging rest intervals. Discard your fastest and slowest split and average the remaining splits. That average approximates your marathon finish time. For instance, if your 800m average was 3:30 (7 min/mile pace for the 800m), that equates to a 3:30 marathon (8 min/mile pace).

History of Yasso 800s

The Yasso 800s workout is named after its creator, Bart Yasso, a former chief running officer at Runner’s World. He had been doing the 800s workout for 15 years, which always helped predict his marathon times. 

"I've been doing this particular workout for about 15 years," Bart said, "and it always seems to work for me. If I can get my 800s down to 2 minutes 50 seconds, I'm in 2:50 marathon shape. If I can get down to 2:40 (minuses), I can run a 2:40 marathon. I'm shooting for a 2:37 marathon right now, so I'm running my 800s in 2:37."

Predictor of Marathon Time

Is the Yasso 800 workout an accurate predictor of marathon time? The theory seems most empirical from my research based on the results from Bart. So, Yasso 800s predict a marathon time- at least for Bart.

However, I have always been dubious in my experience. A 10 x 800m workout faster than a marathon pace is challenging. But does it translate into marathon pace? In my experience, a more accurate predictor is running at marathon pace. An 8, 10, or 12 mile workout at marathon pace is a decent indicator of marathon fitness, especially when part of a training block where you run on tired legs. Having 800m speed is beneficial, but not if your body is not trained to run 20+ miles and efficiently burn fat and fuel. Long runs only train that system. If your long-run adaptations are lacking, Yasso 800 speed will not help you.

Moreover, I asked my running coach (2:15 marathoner and Olympian – let me know if you want his contact information because he’s extremely good), and he sees the workout as an indicator of progressive fitness through the years more than a predictor of marathon times.

Poll Results: Are Runners doing Yasso 800s?

I polled the Runner’s Group on LinkedIn to see what they thought:

Interestingly, almost half of the runners have never heard of the Yasso 800. Of the remaining, the results were split between doing and not doing the workout.

What is your take? Are Yasso 800s part of your running training for a marathon, half marathon, or middle-distance running?

Best wishes on chasing your running goals,

-George

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