The Yasso 800 Marathon Workout

Runner on track

The Yasso 800 workout is a simple way to estimate how long it would take you to run a marathon. Learn how to make it part of your training here…


All of us have a favourite run, be it the long Sunday morning effort, the midweek tempo or Monday-night track session. Well, once you’ve read today’s blog, there’s a very good chance that you’ll have a new contender: The Yasso 800s workout

We’ll delve into the detail shortly but these 800m repetitions were created by American running legend Bart Yasso.

Yasso’s achievements stretch to completing races on all seven continents, winning the 1987 National Biathlon Long Course Championships, taming five Ironman triathlons and finishing the small matter of the Badwater Ultramarathon – aka 146 miles in the deathly heat of Death Valley, California.

Many years ago, Yasso hit upon the idea of running 800m repetitions when training for the Portland Marathon. His aim? To build up to 10 sets of 800m to match his marathon goal time. Make sense? Arguably not.

But this is what Yasso told Runner’s World magazine: “I’ve been doing this workout for years. If I can get my 800s down to 2mins 50secs, I’m in 2:50hr marathon shape. If I can get the 800s down to 2:40mins, I’m in 2:40hr marathon shape.”

It just works…

For Yasso and thousands of others, this seemingly simple principle worked every time: build up to 10 sets of 800m where your average for each set comes in at roughly the same time and your marathon time will, albeit in hours and minutes, not minutes and seconds, mimic that 800m time.

Why does it work? That’s the eternal question. While many predictive models are complicated affairs, trying to marry physiological factors, like aerobic and anaerobic capacity, with performance outcomes, the link between 10 sets of 800m and goal marathon times seems purely coincidental.

Does that matter? Arguably not, as this is a predictor workout. You’re not necessarily looking to build stamina with this workout or top-end speed – it’s all about gauging where you are at that particular moment with an eye on your goal marathon.

As for recovery time between each 800m, it couldn’t be simpler: you simply jog for the same number of minutes it took you to run the repeats. So, if you ticked off 800m in 4mins, for example, jog for 4mins. Ideally, you’ll complete 10 sets a couple of times before your marathon with the last effort around three weeks out.

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Importance of pacing

If the Yasso 800s aren’t a regular in your training plan, you might ask why you need them at all? Simply put, it’s down to pacing. Optimum pacing is the Holy Grail of endurance events, especially races as long as a marathon. It’s where you manage a host of bodily feelings in order to maintain a sustainable pace.

In other words, you don’t get over-excited at the start, use up your energy and hit the wall around mile 21-22 (a common one!), and you don’t start so slowly that despite hitting the finish line in fresh(-ish) shape, your way behind your goal time.

Key to run pacing is experience. Whether it’s conscious or sub-conscious – theories abound around the brain’s role in fatigue and pacing – the more you’ve run, the more competitions you’ve completed, the better you become at managing speed, distance and energy levels. This often manifests itself as even pacing where, to near metronomic levels, you reel off mile after mile at roughly the same time before unleashing that final kick within sight of the finish line.

Negative pacing’s another proven method to reach your targets. As the name implies, it’s where you run the second half of your marathon quicker than the first. This delivers the added ego boost of passing many of the runners who overtook you at the start!

Ultimately, the Yasso 800 workout is just one method to predict your marathon time. There are others – including some excellent ideas in our previous blog “How to Pace a Marathon“. And like all predictive models, the Yasso 800 isn’t foolproof for all with some saying it predicts a marathon time that’s up to 5mins too fast.

Still, history suggests it’s reliable enough for most and is a great way to not only gauge your marathon time but also provide a boost of motivation when your race is still way off on the horizon.

Phil Mosley (Coach & Founder)
Phil Mosley (Coach & Founder)

Phil is a recognised endurance expert who founded MyProCoach in 2010 to offer smart training plans that still leave quality time for your family, friends & career - complete with highly-rated coach support (he has sold over 40,000 so far). Learn more here!

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