Yasso 800s Guide: How To + Marathon Time Predictor

Can this workout really predict your marathon time?

Yasso 800s are a classic speed workout that is widely used by distance runners.

Yasso 800s have become a staple track workout in many marathon training plans – and can be used to predict your marathon finishing time (we’ll get into how accurate they are later).

Today, we will discuss Yasso 800s in-depth and see if they should be included in your marathon training plan.

A person running on a track.

What Are Yasso 800s?

Yasso 800s is a workout designed to improve your speed and claims to be able to predict your marathon finishing time.

The inventor of the workout, Bart Yasso, came up with this training session and says he would use it to determine his fitness level going into a marathon.

Who Is Bart Yasso?

Bart Yasso was the Runner’s World Chief Running Officer and is a bit of a legend in running circles. He has been dubbed by many as “the mayor of running.”

Yasso’s running accomplishments are worthy of mention:

  • He’s run marathons on all seven continents.
  • He won the U.S. National Biathlon Long Course Championship in 1987 and the Smokey Mountain Marathon in 1998.
  • He has also completed 5 Ironman races and the legendary Badwater Ultramarathon.

To further cement his legacy, Bart Yasso has been inducted into the Running USA Hall of Champions.

yasso 800 workout marathon training

How Do You Properly Perform Yasso 800s In A Running Workout?

The goal of Yasso 800s is to build up to 10 x 800 meter intervals on a running track.

The amount of time, minutes and seconds you can hold for the workout are supposed to correlate to the hours and minutes it will take you to finish the marathon.

For example, a runner who can run 3 minutes and 20 seconds for all the 800m repetitions should theoretically have a marathon finish time of 3 hours and 20 minutes.

Many marathon plans will have you do several sessions of Yasso 800s spread out over a 12-16-week program.

Some earlier sessions will start with 4-6 reps of 800m. Throughout your training, you will add reps to the session until you can complete 10x800m at your marathon goal time pace.

How do you incorporate Yasso 800s into a marathon training plan?

A sample 16-week schedule for a 4-hour marathoner could look like this:

Week 3: Yasso 800s
4x800m in 4 mins with 4 mins recovery

Week 7: Yasso 800s
6x800m in 4 mins with 4 mins recovery

Week 11: Yasso 800s
8x800m in 4 mins with 4 mins recovery

Week 15: Yasso 800s
10x800m in 4 mins with 4 mins recovery

yasso 800 workout marathon training

Yasso 800s: Is It An Accurate Marathon Result Predictor?

Yasso 800s are a popular workout to predict your marathon finishing time, but are they really accurate?

A quick Google search will lead you to a host of articles and runners praising the workout and saying that it accurately predicts their finishing time.

Bart Yasso himself has said that when he can do the reps in 2:45, he has run a 2:45 marathon. Same for 2:50 and even as specific as 2:37.

On that same Google search, you will likely find a lot of coaches and athletes telling you that Yasso 800s are a poor predictor of marathon finishing times.

Running coach Jeff Galloway, among other coaches, believes there are better workouts you can run to prepare yourself for the marathon and predict your finishing time.1Jeff Galloway | The official site of Run-Walk-Run. (n.d.). Retrieved February 15, 2024, from https://www.jeffgalloway.com/

While Yasso 800s are a popular workout for predicting your marathon finishing time, the truth is there is no scientific data that shows that it does so accurately.

For some runners, there may be some correlation between the workout and their finishing time, but this is far from a guaranteed occurrence.

So you can consider your Yasso 800 timings to be a ‘rough guide’ of your marathon finishing time, rather than a clear indicator.

yasso 800 workout marathon training

Are Yasso 800s a Good Workout For Marathon Training?

In reality, Yasso 800s are not a great marathon-specific workout.

When designing a workout for a specific race, two things should be considered: the length of the race and the pace that will be run

Most workouts should be focused on helping the runner prepare for one or both of these variables.

The marathon is 99% aerobic.

Workouts for the marathon should be designed around running close to your goal pace. These could include:

The purpose of the workouts would be to have the body experience the demands of your marathon pace and develop adaptations to be able to hold it for the full marathon distance.

A Yasso 800 workout is going to have you running paces that will be anaerobic.

While there are benefits to doing an anaerobic workout during your marathon training, this workout will not be specific to the demands of the marathon.

The reps will be too short, and the rest will be too long.

yasso 800 workout marathon training

For example, let’s say we have a runner hoping to run a 3-hour marathon to qualify for the Boston Marathon.

If this runner were to do Yasso 800s, they would need to run two laps around the track in 3 minutes.

This would be a 6-minute mile pace. A 3-hour marathon is the equivalent of running a race pace of 6:52 per mile. That’s almost a 1-minute difference in pace.

For this runner, the 6-minute pace is closer to their 5k or 10k race pace.

So our runner is doing 5 miles of intervals at 5k-10k pace while getting 3 minutes of rest between each rep.

This isn’t a workout that will produce meaningful results for a runner hoping to improve their marathon time through speedwork.

So what should you do instead?

The marathon is a difficult race.

Most runners will be running for 3.5-5 hours. This is a long time to be on your feet. Fueling becomes important to avoid hitting the wall, as does pacing correctly so you don’t bonk with several miles of race left.

A good marathon workout should have you practicing the marathon pace for extended periods of time. This can be achieved through several different workouts.

Here are a few examples:

yasso 800 workout marathon training

#1: Long Run With A Fast Finish

A great marathon workout can be implemented in most of the long runs you are already doing.

Set off on your long run as you normally would. However, for the last 30-60 mins, you will increase the pace to your marathon pace. An example of our 3 hour marathoner could look like this:

10 miles at easy/moderate pace (7:30-8:00 per mile)
4 miles at marathon pace (6:52 per mile)
2 mile cooldown
Total: 16 miles

This run will accomplish several goals that make it a better marathon workout than Yasso 800s:

  • Running your actual marathon pace and getting a feel for it.
  • Running your marathon pace on tired legs which will prepare you for the later miles in the race.
  • Allow you to practice fueling on longer runs and while running at marathon pace.

This workout can easily be adjusted for more or less time at pace and longer or shorter distances.

yasso 800 workout marathon training

#2: Cut Down Intervals

This is a great workout to get in a lot of time at marathon pace with some short jogging breaks to recover. These can be broken down into miles or minutes. Some examples could include:


  • 5 miles at marathon pace, 5 minutes easy recovery jog
  • 4 miles at marathon pace, 4 minutes easy recovery jog
  • 3 miles at marathon pace, 3 minutes easy recovery jog
  • 2 miles at marathon pace, 2 minutes easy recovery jog
  • 1 mile at marathon pace, 1 minute easy recovery jog


  • 25 minutes at marathon pace, 3 minutes easy recovery jog
  • 20 minutes at marathon pace, 3 minutes easy recovery jog
  • 15 minutes at marathon pace, 3 minutes easy recovery jog
  • 10 minutes at marathon pace, 3 minutes easy recovery jog
  • 5 minutes at marathon pace, 3 minutes easy recovery jog
People jogging on a track.

Both of these workouts provide you with double-digit miles run at marathon pace while giving you short breaks to recover.

The workouts can easily be scaled down by removing the first, longer interval or by increasing the recovery between the reps.

For these workouts, be sure to do a proper warmup and cooldown.

These workouts will give you a much better idea of what your marathon finishing time will be.

While no workout will predict your finishing time with 100% accuracy, long workouts run at your goal marathon pace will be a much better indicator of your finishing time than Yasso 800s.

Should You Do Yasso 800s In Your Marathon Training?

Yasso 800s can be used as a training run in your marathon training.

They will provide an anaerobic stimulus and are a great workout to push the pace and get some leg speed.

However, there is no scientific evidence that they will accurately predict your marathon finishing time.

My advice: Find other workouts that will better mimic the demands the marathon will place on your body.

If you want to throw in one session of Yasso 800s towards the end of your training for fun, go for it.

However, to get the most bang for your buck, I would skip doing several sessions of these and focus more on workouts at or around marathon pace for lengthy periods of time. 

For more long run variation ideas, check out this next guide:


Photo of author
Adam Rabo has been running since junior high. He has coached high school and college distance runners. Adam recently completed the UTMB Canyons 100k, making the cutoff for the Western States 100 and UTMB. You can generally find him on the rodes or trails in Colorado Springs, training for upcoming marathons and ultramarathons.

5 thoughts on “Yasso 800s Guide: How To + Marathon Time Predictor”

  1. Thanks for taking the time to write this up and offer advice. However, I think the criticism of the 800s for a marathoner is a bit misplaced. If used in the marathon context – the traditional Yasso 800 workout, rather than an 800m race workout – there shouldn’t be an anaerobic aspect to it. For example, a 4 hour marathoner is running about 9 min miles during the marathon. Yasso 800s at 4 min for a half mile is 8 minute pace. If someone is going anaerobic at 8 minute pace in just half a mile, then they definitely won’t be able to hold 9 minute pace for a whole marathon. And if someone can reach the anaerobic threshold for 10 reps of 800, that’s an extremely impressive speed workout that would leave them totally wiped out. To be able to run 10 800s at marathon pace means you should be running all those aerobically. Early in the training block, it’s more of a speed building workout to develop the leg turnover and get the central nervous system accustomed to running those speeds. By the end, it’s a great way to get a marathon pace workout in that won’t beat up the body much and allow you to hit another good workout after a day off.

    • Spot on Chris.I’ve used Yasso 800s for years with athletes and they have worked consistently well. They provide a good training load and are aerobic. They are designed to complement long training runs with segments of marathon pacing rather than replace such runs.

  2. Agreed! Today I ran 3 mi WU/ 10 x45″ hill attacks + 30″ sprints at the top of the hill off 2’30” jog backs/ 3 mi easy/ 6 x 400m in 3’07” – 2’53” off 1’30 rec./ 3 mi CD and the 800s really left my legs in a great place, not beat up.
    My goal marathon is 2’53 first sub 3 try ( currently sitting at 3’02)
    20 mi run coming Friday with 2 WU/ 16 mi @mp/ 2 CD


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