Superstar Workout: Yasso 800s

In Runner’s World a couple of decades ago, columnist Amby Burfoot described a workout he heard about from Bart Yasso, a colleague at the magazine. The workout: 10 x 800 meters with approximately 400-meter easy running recovery. Burfoot coined the name Yasso 800s, and the workout became a part of training lore.

I have always thought that it’s super cool to have a legendary workout named after you. What a power move. I am just hoping one of my Trail Runner Magazine colleagues takes notice of some of my novel ideas and comes up with “Roche Boxes.” That’s a recovery-focused workout where you eat an entire box of children’s cereal before lunch.

The mystery lurking within Yasso 800s is what made them such a storied workout. 

Theoretically, the pace an athlete could average on the 10 intervals would predict marathon time. Yes, you heard that right. It’s a MAGIC WORKOUT.

4 minute average for the intervals? 4 hour marathon. 3:20 intervals = 3:20 marathon. I could do this all day because I rock at numbers.

Unfortunately, that connection is tenuous at best. Most athletes could run a bit faster on the intervals than their predicted marathon time, though perhaps very slow-twitch athletes would be closer to accurate. And even if it were accurate, it would be based on a coincidental association rather than a causative one. However, we shouldn’t throw the baby out with the bathwater. It’s drought season and bathwater isn’t cheap!

What the workout lacks in uniform predictive value, it makes up for by targeting adaptations that can support performance at almost all distances from the 5K up to ultramarathons. I’d argue that the principles of Yasso 800s make it one of the best all-around workouts possible.

Sure, Yasso 800s are not that accurate as a predictor, and a race or long tempo would be better for those purposes. But what the workout lacks in uniform predictive value, it makes up for by targeting adaptations that can support performance at almost all distances from the 5K up to ultramarathons. I’d argue that the principles of Yasso 800s make it one of the best all-around workouts possible.

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Yasso 800 Principles

In Eluid Kiphchoge’s training log before setting the world record in the marathon, you’ll see lots of intervals between 2 and 3 minutes (including 10 x 800 meters) with a couple minutes easy recovery. Tinman Elite athletes do plenty of intervals of similar duration. And 2-to-5-minute intervals with solid recovery are staples of most training programs. There are a few reasons why.

First, when intervals are too short or have too much and/or too easy recovery, athletes may go too hard for optimal adaptations. Too many all-out anaerobic intervals can reduce aerobic efficiency over time due to feedback cycles with capillary formation through angiogenesis, aerobic enzyme activity, lipid oxidation/metabolic factors, and muscle fiber recruitment. That’s why excessive high-intensity interval training can risk creating tough, strong, inefficient (and ultimately slower) athletes. Yasso 800s are long enough that most athletes need to dial back the intensity to VO₂ max or easier, and I’d recommend doing them easier still outside of periodic supercompensation workouts.

Second, when intervals are too long relative to fitness abilities, form and output may deteriorate rapidly for many athletes. It varies by the person, but a good general rule is that grinding out long intervals makes an athlete better at grinding, rather than necessarily making them faster, particularly for non-advanced athletes. If instead they get faster by improving running economy via shorter intervals, they can make it so that the later grinds are faster. That speed should also correlate to stronger climbing.

Because there are 10 intervals, athletes can’t go out too hard and risk aerobic regression or burning out over the course of the workout. But it’s not so long athletes need to intentionally slow themselves down to a jog. Not too hot, not too cold. A good workout for Goldilocks before she gets cancelled for being a jerk to bears.

Third, intervals like Yasso 800s hit a sweet spot between aerobic and musculoskeletal adaptations, where adaptation stress and injury risk are most balanced. Because there are 10 intervals, athletes can’t go out too hard and risk aerobic regression or burning out over the course of the workout. But it’s not so long athletes need to intentionally slow themselves down to a jog. Not too hot, not too cold. A good workout for Goldilocks before she gets cancelled for being a jerk to bears. My guess is for why it has some marathon-time predictive value is that it’s a proxy for overall fitness at a middle-ground effort range that correlates well with performances of all distances, not just the marathon.

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Applying Yasso 800 Principles in Your Training

My twist on Yasso 800s is that I think most runners probably shouldn’t be on the track too much. The track is often where love of running gets cancelled. Also, I don’t think the goal should necessarily be averaging the fastest pace you can across all of the intervals. Those all-out, supercompensation stimuli are good in moderation, but most workouts should be more relaxed to avoid injury and provide sustainable adaptation stress. So start with the dial set to “hard from the start,” then turn it back a couple notches to “fun with a sprinkle of hard at the very end.”

Some ideas for trail runners, all with a warm-up and cool down of 20ish minutes of easy running.

6-8 x 3 minutes fast with 2 minutes easy recovery. This type of workout can be done on trails, mixing up movement patterns while avoiding excessive wear-and-tear from 10 intervals. If I could only give one workout to advanced athletes to combine with normal trail running and strides, it may be this one.

5/4/3/2/1 minutes fast with 2-3 minutes easy to easy/moderate recovery. The ladder workout has similar total volume, but with a step-down progression that may allow some athletes to maintain more focus, while finishing faster.

5-8 x 3 minute hills with run down recovery. On the first hill, note the spot you get to after 3 minutes, and run each interval after to the same spot without looking at your watch. Doing the intervals on hills reduces impact forces and may be best for athletes worried about injuries or recovery cost.

Yasso 800s are not a magical predictor workout. But do enough sustainable, consistent intervals like Yasso 800s over time, and it can seem magical for fitness progression.

David Roche partners with runners of all abilities through his coaching service, Some Work, All Play. With Megan Roche, M.D., he hosts the Some Work, All Play podcast on running (and other things), and they wrote a book called The Happy Runner.