How to do Yasso 800's | Can They Predict Marathon Time?

Runners love the idea of predicting a marathon finishing time and hence the long standing legend of the Yasso 800’s. A simple, yet tough, speed workout designed by the renowned runner and writer Bart Yasso. He formulated a concept where running ten 800-meter intervals might foretell one’s marathon finishing time.

This unique training concept has become a cornerstone for many marathon hopefuls looking to boost their speed and endurance.

The beauty of this exercise lies in its uncomplicated nature, making it useful to runners of all levels. Yasso 800s offer a structured yet flexible training method that you an use to progress over the course of a training cycle.

Let’s find out more about this classic workout and how people use it to determine a potential marathon performance.

*As a running coach, I have to remind you that this is but one of many tools and that even Bart himself, a long time editor at Runner’s World and high performance athlete, has said it’s not a perfect correlation of race day performance.

Quick Jump

What Are Yasso 800s?

Coined by renowned runner and coach Bart Yasso, Yasso 800s involves running 10 repetitions of 800-meter (or half-mile) intervals at a pace correlating to your target marathon time. The idea is if you can hit each 800m repeat at your goal time, then it’s a good prediction of your marathon finish.

For those unfamiliar with the mechanics, the execution of Yasso 800s involves running repetitions at a pace that corresponds to the hours and minutes of your goal marathon time.

For instance, if you’re targeting a marathon finish time of 3 hours and 30 minutes, your goal pace for the 800-meter intervals would be 3 minutes and 30 seconds.

You are NOT running the laps at your goal pace, but rather at your threshhold running pace. Which is what makes this such a tough workout and should only be one piece of a marathon training plan. We also want miles at goal marathon pace, tempo run work and more.

While the workout is not an infallible predictor, it provides insights into your current fitness level and serves as a tangible marker of progress throughout your training journey. Even Yasso himself says this is but one of many factors, though regardless it’s a great speed workout to execute during training.

This personalized approach adds a dynamic element to training, allowing each runner to tailor their Yasso 800 workouts to their specific goals and aspirations.

A key note before we get in to more details is that you SHOULD NOT try 10 repetitions on your very first attempt at this workout! Instead, this is something that you are building over the course of your training plan.

Executing the Yasso 800s Workout

The first step in this process will be determining your marathon goal time. This process is going to involve looking at your existing race performance and how much time you have for this training cycle. Remember that on day one this pace is going to feel hard and will slowly feel more doable throughout training.

In your first Yasso workout, complete only 2-3 reps depending how much other speed work you’ve been doing. And if you aren’t familiar, read up on how many laps make a mile to make sure you’re running the right distance.

Warm Up Prior to the Speed Session

Before I dive into the Yasso 800s workout details, know that warming up is non-negotiable for priming muscles for the workout ahead.

A thorough warm-up is crucial before high-intensity running workout. The goal is to gradually increase your heart rate, warm up your muscles, and prepare your body for the demands of the upcoming workout.

Start with a dynamic warm up (no static stretching) to loosen up and prevent any strains.
Move in to 10 minutes of easy running to warm up the muscles and slowly increase heart rate.
Consider doing 3-5 running strides
And doing 3 to 5 minutes of running form drills – A-Skips, fast feet, etc.

A proper warm-up not only reduces the risk of injury but also enhances your overall performance during Yasso 800s and similar workouts.

how to do yasso 800's

Start The Workout

Ideally you’ll perform this on a track or other measured area so you don’t need to check your watch or account for variations in elevation while running. This workout is designed for a specific purpose of pacing, where you can do other speed sessions on the roads to incorporate hills.

Run the First 800-Meter Interval: Hit the track and cover 800 meters, timing yourself to match the minutes and seconds of your targeted marathon time in hours and minutes. For instance, if you’re eyeing a 3-hour marathon, run the 800 meters in 3 minutes.

Recovery Jog: Follow up your hard effort with an equal-time jog. For the 3-hour marathon goal, you’d jog for three minutes. Match your recovery time exactly to the time you ran your 800 intervals to maximize the workout’s effectiveness.

Repeat the Process: Alternate between running and recovery until you complete your set number of 800-meter runs. Start with three intervals and add more as you progress, but only when you consistently meet your time goals.

Remember the goal is not to run faster, but to run the prescribed time.

And we will max out at 10 intervals for this workout, likely in the 3-4 weeks before your marathon.

How Many 800 Repeats Should I Do?

As noted, start with 4, especially if you are doing this early in the training cycle.

The goal is to max out at 10 repetitions if you’re using this as some kind of predictor workout in your marathon training.

What Are the Benefits of 800s?

These workouts provide a number of benefits across a range of training goals. Let’s breakdown a few of them:

Running at faster than marathon pace will make marathon goal pace feel easier
It can help with that finishing kick because you’ve learned to push hard on tired legs
You’ll be improving your VO2 Max, which means more efficient running
Short, sharp speed sessions are going to push you to your max quickly and then allow you to recover

Post Yasso Workout

After each session, consider your performance. Were you able to sustain the pace? Only increase the number of intervals when you can confidently complete your current set at the desired pace.

Additionally, after an intense track workout, it’s important to follow a good post run cooldown protocol. Remember that we do not want to sit down and we absolutely must make refueling and hydrating a priority to be ready for the next workout.

Begin with a slow jog, letting your heart rate decline gradually. This gentle activity aids in clearing your muscles of lactic acid and reducing stiffness.

How Often Should You Do Yasso 800s?

While it’s good to repeat workouts throughout your training cycle to see progress, it’s also really valuable to incorporate other speed sessions.

We want to do things at 5K pace, goal marathon pace and everything in between over the 12-16 weeks that you’ll be training.

Since we aim to keep our total intensity volume of training to 20% or less for any given week, you might only do Yasso 800s 1 time per month alongside your other workouts.

Using Yasso 800s for Other Races

If you’re gearing up for a race that’s shorter than a marathon, you might think Yasso 800s aren’t for you. I’ll let you in on a secret: you can still use them to boost your speed and endurance. Start with four repeats and pay attention to how your body responds.

Say your goal is a half-marathon time of1:45 finish. Aim to run 5 by 800 meters in 3 minutes and 37 seconds (which would be your equivalent marathon finishing time).

Once you nail all your repeats at this pace, only then consider adding another.

Training for a 10K? Adjust your repeats to suit your race pace, focusing on completing each 800-meter interval consistently before increasing the number.

This is about building endurance methodically, without overtaxing yourself before you’re ready. Stick to the core principle of the workout: maintaining the target pace for each interval before progressing. It’s this steady increase that helps you gain strength and speed while tailoring the workout to meet your race goals.

Do I Assign Yasso 800s?

As a long time running coach and runner myself, I can’t say that this is a workout we repeat a ton with most athletes because as noted above there are a lot of things I want us to work on in the 12-16 weeks of a marathon plan build up.

Particularly if you build up to 10 repeats, this is a workout that’s going to require recovery and might take away from some of the other things we want to accomplish during peak marathon training.

I do like using 800m repeats in workouts, but usually do not build up to the full 10. Instead, I have runners start to incorporate goal pace mileage in their long runs, fast finish workouts during long runs, etc.