The 80/20 Theory of Running

Matt Fitzgerald
by Matt Fitzgerald
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The 80/20 Theory of Running

Every runner has goals: Some want to lose weight, others want to gain fitness, and still others seek to improve certain health factors. One of the most common running goals is to run faster over a given race distance.

It usually goes like this: You start off with the goal of finishing your first 5K, 10K or whatever. Once you’ve done that, you establish a new goal of running the same distance again and beating your time (i.e. setting a new personal record, or PR).

It is said that the definition of insanity is doing the same thing over and over again, and expecting different results. Runners are not crazy: They know that in order to perform better than before in a race, they must prepare better in training. The question is, how?

Racing Faster Doesn’t Just Require Running Faster

In the pursuit of greater fitness and better race results, there are two major training variables that you can manipulate: volume and intensity. Volume is how much you run and intensity is how fast or hard you run. If your goal is to set a new race PR, should you run faster or run more miles in training?

The surprising answer is “neither”… at least not initially. Research indicates that there is a certain balance of training intensities that are optimal for runners at all levels of fitness and experience. Specifically, runners improve the most when they do 80 percent of their training at low intensity and the remaining 20 percent at moderate to high intensity. The typical runner does only 50 percent of his or her training at low intensity. This means that, if you are a typical runner, optimizing your training intensity balance will require that you slow down overall.

Increasing the amount of running you do won’t benefit you much until after you have balanced your training intensities according to this “80/20 Rule.” You would actually improve more if you keep your running volume the same and do some of it slower than you would if you run either more or faster.

This may sound too good to be true, but it’s a proven fact. In a 2014 study, for example, researchers divided a group of recreational runners into two subgroups. Some did about 50 percent of their training at low intensity and 50 percent at moderate to high intensity, as the typical runners does. Others did 80 percent of their training at low intensity and the rest at high intensity. The two subgroups did equal amounts of running. After 10 weeks, the runners in the 80/20 group had improved their 10K times by 7%—double the amount of improvement seen in the 50/50 group!

To take advantage of the 80/20 Rule, you need to pay attention to intensity when you run. Low intensity corresponds to subjective effort ratings of 4 and below on a 1-10 scale. You should also be able to talk comfortably at this intensity. Moderate intensity corresponds to ratings of 5-6, and high intensity to ratings of 7 and up. Spend 80% of your total weekly running time at effort levels of 1-4, and the remaining 20% at efforts of 7-10, and get ready to PR!

About the Author

Matt Fitzgerald
Matt Fitzgerald

Matt Fitzgerald is a certified sports nutritionist and author of Diets Cults and 80/20 Running, among other books. He provides real-time audio coaching for runners and other athletes through and one-on-one nutrition coaching through


27 responses to “The 80/20 Theory of Running”

  1. Avatar thohan says:

    A study involving 30 runners does not a fact prove. Interesting results, though.

    • Avatar fdsbg says:

      Actually it does. You need a minimum of 30 data points in order to have a result that is statistically significant. The only caveat is that the 30 runners need to be a random sample which I saw was the case when I clicked on the research study. Also, the study is focused on endurance running, sprinting is not factored in. I would have loved to see a similar article on tips on how to become a better sprinter…

      • Avatar Rickey King says:

        Sorry studies don’t prove anything. They support or don’t support the null hypothesis. The power our number of subjects just supports generalizability . Still a very small sample size.

  2. That’s very interesting..
    Let’s put that to the test then 🙂

  3. Avatar Rej says:

    Your article doesn’t speak to training for different length of races. As a sprinter, I question the applicability of the 80/20 rule.

    • Avatar bcg1220 says:

      I agree. I think that’s a different beast all together. Sprinting and running are definitely two different things.

  4. Avatar Don Anastas says:

    I’ve run in two Chicago marathons finishing in the top 150 twice. During the week I ran 5-7 miles daily. I also worked with a trainer of a Nautilus fitness center 3 x per week. On weekends I ran 10-12 miles on Sat/Sun. The Nautilus training put me over the top. The trainer pushed me hard enough to see progress and positive results which equated to better run times during the week and weekend. I also fit in some 10k runs in my schedule as substitutes for a weekend run and to break up the monotony that will set in.

    Not everyone has the time to take on my training method but if your goal is to run a marathon with very good results than use my formula – MA = MR or massive action equals massive results.

  5. Avatar El Paso Mark says:

    I’m not a runner. I ride. Will/does this work for a cyclist too?

    • Avatar bcg1220 says:

      From a former triathlete: absolutely. I would do a high intensity ride every 4-6 rides depending on how I felt.

  6. Avatar T.R. says:

    This sounds like a modification of a very well established theory surrounding ‘wind sprints’ or HIIT (high intensity interval training) which has more quantitative testing and research.

  7. Avatar DCH says:

    So in practical terms of the 80/20 rule is if I run 5x a week…
    I can do 4 days of light to medium intensity and 1 day of higher intensity.
    Interesting! We all have different conditioning levels but that seems like a balanced approach.

    • Avatar SheaChez says:

      Have you tried that method? I am unclear on how to make this work. I wondered if you are running say 5k, do you go slow for 4k, then hard for 1k? Or is it better slow for 4 days, then one intense day? No specifics given here…

  8. Avatar Bridget Roberts says:

    I know my husband, as a sergeant in the military, would help coach his Joes when they didn’t make time for their PT tests. He’d tell them all to speed walk everywhere they went as part of their training instead of just running their times down. The walkers usually saw the most improvement and were able to pass the next go round 🙂

    • Avatar dclaudew says:

      Hmmm, speed walking would push their intensity to moderate (say 3.8 – 4.1 MPH) or intense (say 4.2+ MPH). I have to agree with you. If I push my heart-rate monitor to intense workouts (say 80% max), I experience about the same long-term endurance benefits from very fast walking as if I had pounded the pavement with a real run. I’m not sure anyone ever failed the PT tests in my Army days (1967-70), although we would sometimes go on long runs and some troopers would walk home from the turnaround point. 😉

  9. Avatar bcg1220 says:

    Makes sense. Coming from soccer, we were always in the best running shape of any athletes including most of cross country and track. If you think about a soccer match it’s probably close to an 80/20 workload. As were our practices.

  10. Avatar Rachel Hamrick says:

    This isn’t quite like HIIT. I’ll also say that high intensity running all the time will tire your body out, which will lead to injuries.

    I believe what the 80/20 method is would be to split your training into portions, so you wouldn’t be constantly sprinting or jogging or whatever.

  11. Avatar Felita Viruet Delikat says:

    I think the idea is more that low int 80 is less stress on body and that 20 percent your body is warm and loose and you do high intensity with ease as per my experience.
    it makes you focus on that high part and keep form and breathing good instead of doing 50 50 with poor form and breathing.

  12. Avatar Bobby Kawasaki says:

    I have a pet peeve about articles like this because if you read the authors bio, it seems to me that specifics are lacking because… it’s a sales pitch! A very interesting topic but the author withholds any good information unless you buy the book. The article is an advertisement disguised as content on a site known for the value the fitness community as a whole contribute to it for FREE!

  13. Avatar Neil Russell says:

    For any study such as this, the conclusions reaped from tests results are invalid until you show that similar results occur as you do multiple trials, I.e. you have to show repeatability.

  14. Avatar Neil Russell says:

    Very similar to the training routine used by Gerry Lindgren back in the sixties. He would do most of his runs at slower speeds, then intersperse sprints here and there. His book never gave a ratio, but I always felt it was in the 80/20 range, give or take.

  15. Avatar Si says:

    This doesn’t account for available time though – if the trial runners covered the same distance at different intensities then the low intensity runners must have taken longer. When you are generally short on time as I tend to be there isn’t really an option of running for longer at lower intensity

  16. Avatar Kelly Carter says:

    How about some specific examples of how to apply this 80/20 rule? Or is this article just a tease to make you buy the author’s book to get any truly useful information? I’m totally OK with people selling books, but I’m more likely to find a writer credible if they also try to be useful without necessarily having the profit motive.

  17. Avatar Mike Panacek says:

    I started a training program earlier this year that roughly follows the 80/20 rule and have seen great results. It’s a litle hard for me to keep my speed down for Heart Rate Zone 2 and can’t help but push that a little into Zone 3. It seems to me though that the low intensity is training your body to work more efficiently in using the available oxygen and energy. I still try to run as fast as I can, but while keeping my heart rate in a “conversational”zone.

  18. Avatar Brian Theoret says:

    Interesting and something to think about!

  19. Avatar Keith says:

    Can u base this on heart rate? I average about a 12 minute mile which is not fast. Maybe do 0.8 at 13 mph and 0.2 @ 10.


  20. Avatar Justin Gittemeier says:

    I’m a little confused on how to apply the 80/20 theory. What heart rate percentages would you say are low intensity and high intensity (I think effort 1-10 is too hard to estimate)? And should you do 20% of your workouts at high intensity or 20% of each workout at high intensity?

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