Yasso 800s Explained: A Simple Trick to Predict Your Race Time

Yasso 800s are a legendary track workout known not just for building speed but also for predicting marathon times with surprising accuracy.

The concept is simple: however many minutes it takes you to run 800 meters, that same number (in hours) is your predicted marathon finish time.

For example, if you consistently run your 800s in 3 minutes and 45 seconds, you're likely in shape for a 3:45 marathon.

It’s one of the most straightforward, effective speed workouts out there and once you learn how to do it, it becomes a powerful tool to improve both speed and endurance.

Where Yasso 800s Come From

This workout was developed by Bart Yasso, a longtime running ambassador and former Chief Running Officer at Runner’s World.

Bart spent years fine-tuning this workout and found it consistently lined up with his marathon performances.

“I’ve been using this workout for 15 years,” Bart said. “If I’m running my 800s in 2:50, I know I’m in shape for a 2:50 marathon. If I’m down to 2:40, then I know I’ve got a 2:40 race in me.”

Why Yasso 800s Work

Here’s what makes Yasso 800s so effective:

• They build race-specific endurance and speed.
• They train your body to perform under fatigue.
• They’re simple to remember and easy to measure.
• They double as a pacing and prediction tool.

Running 10 intervals of 800 meters with equal time jog recoveries forces your body to adapt and become more efficient. And because it’s easy to plug the workout into your GPS watch or treadmill, it’s incredibly accessible for all runners.

What Exactly Are Yasso 800s?

Yasso 800s are 800-meter intervals (half a mile or two laps on a standard track), repeated 10 times. Between each interval, you jog for the same duration it took to complete the last 800. So if you run your interval in 4:00, your jog recovery is also 4:00.

They can be done:

• On a track
• On a treadmill
• Or outside using a GPS watch or running app to track distance

How to Do Yasso 800s Step-by-Step

1. Warm-Up: Jog for 10 minutes at an easy pace. Add in dynamic stretches to prep your body.
2. Run Intervals: Run 800 meters at your marathon goal time in minutes. So for a 4-hour marathon goal, run each 800 in 4:00.
3. Recover: Jog for the same amount of time as your interval.
4. Repeat: Aim to build up to 10 total intervals.
5. Cool Down: Jog for 10 minutes and stretch post-run.

Pro Tip: Don’t worry if you can’t start with 10 intervals. Begin with 4 or 5 and gradually increase adding one interval each week only if you can consistently hit your target pace.

Sample Yasso 800 Workout

• Warm-Up: 10-minute easy jog + dynamic stretches
• Intervals: 800 meters x 10 @ goal marathon time in minutes
• Recovery: Equal-time recovery jog between each interval
• Cool Down: 10-minute jog + post-run stretch

Modifying the Workout for Shorter Distances

You don’t have to be marathon training to benefit from Yasso 800s. Here’s how to tweak the workout:

• Half Marathon: Start with 5 intervals at your 10K pace.
• 5K/10K: Do 4 intervals at 30 seconds slower than your 5K pace.

Even if you’re not chasing marathon dreams, this workout builds aerobic power and fatigue resistance critical for all race distances.

Frequently Asked Questions

What is the Yasso 800 method?
It’s a speed workout made up of 800-meter intervals that align with your goal marathon time. Run 800s in the same minutes as your marathon goal hours (e.g. 3:30 intervals = 3:30 marathon).

How fast should I run each interval?
Take your marathon time goal in hours and match it in minutes. A 4:30 marathon means running 800s in 4 minutes and 30 seconds each.

What’s the biggest benefit?
It’s both a fitness booster and a marathon predictor. Plus, it’s simple and scalable for different distances.