Of course, you don't want to run the full Yasso 800m workout the first time you try it, or if it's very early in your marathon training, start with just four to six repetitions and add one to two reps every two to four weeks until you reach 10 repeats.
Add up all the recovery running and repetitions (including warm-up and cooldown jogs) and you'll notice this is a relatively long day of running—close to 10 miles. Make sure you're ready for this training volume.
A Word of Caution About Predictor Workouts
Yasso 800s are predictor workouts—they help you determine your eventual marathon finish time. That's a very helpful tool in your running toolbox, but don't make the mistake of completing only running predictor workouts.
It's more helpful to run workouts that form the foundation of sound marathon training, such as tempo, progression, and long runs—especially long runs with some mileage run at your goal marathon pace.
Runners who choose to run Yasso 800s will be best served to complete them only two to three times in an entire 16 to 20 week marathon training plan. These track workouts will give you the confidence that you're on the right path to accomplishing your next marathon PR.
But for most of your training, it's more beneficial to stick with workouts that are run at or near your goal marathon pace. This is training specificity at its finest. You have to run workouts that are specific to the distance and demands of your goal race.
But occasionally, you can run a session of Yasso 800s to help predict your marathon finish time. It's not one of the world's most famous workouts for nothing!race.