Want To Get Faster? Try Out The 80/20 Running Method

Here's why more slow runs and less speed work is the answer.

When I coached high school track and cross country, there was an assistant coach who would tell the runners, especially during the long, slow, base-building summer runs, you’ve got to go slow to go fast.

They would look at him skeptically, but his advice, while perhaps counterintuitive, is actually quite sound.

Research has shown that while we may instinctively feel a need to push the pace most of the time to run faster, doing most runs at a slow pace is more likely to yield the desired results.

According to runner and fitness expert Matt Fitzgerald in his book 80/20 Running, running too hard too often is “the single most common and detrimental mistake” made by runners, as the “secret” to becoming a faster runner is “going slow most of the time.”

If you suspect you’re running too many miles too fast and are curious about the potential benefits of the 80/20 running principle, keep reading!

Want To Get Faster Heres Why More Slow Runs And Less Speed Work Is The Answer

What is the 80/20 running Rule?

Arthur Lydiard

In the 1960s, New Zealander Arthur Lydiard devised a training method for runners that emphasized slower running with a relatively small amount of speed work.

His method was adopted by endurance athletes, who had success with it. Elite athletes continue to follow his ideas and run most of their miles at an easy, conversational pace.

Recreational runners or beginners, however, have been less inclined to follow this method and tend to run at least half of their miles at a moderate or hard training intensity.

Runners’ resistance to slower running appears to be based on skepticism that slower running can be beneficial, but research has confirmed its benefits.

Lydiard advises new runners to take the word “hard” out of their vocabulary and slow down, explaining that easy running will result in gradual and important physiological changes and adaptations, including strengthening your muscles, joints, and ligaments.

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Stephen Seiler

Stephen Seiler, an exercise physiologist and Sports Science professor at the University of Agder in Norway has conducted extensive research on endurance training and intensity distribution and confirmed Lydiard’s theories.

Seiler analyzed high-level athletes in various sports, including runners, and discovered that most world-class athletes do approximately 80 percent of their training at low intensity and 20 percent at high intensity (now often referred to as the 80/20 rule or 80/20 training).

Seiler then designed studies in which athletes were divided into two groups—one that followed an 80/20 plan and one that did more hard training.

He consistently found that the athletes who followed an 80/20 training plan experienced significantly more improvement than athletes who did more than 50 percent of their training at a higher intensity or even those who followed a 65/35 plan.

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Why Does The 80/20 Running Plan Work?

While testing has consistently confirmed that an 80/20 running plan yields the best results, scientists are not entirely sure why this is so.

As indicated by Fitzgerald, theories include180/20 Endurance. (n.d.). 80/20 Endurance. https://www.8020endurance.com/ that low-intensity training is more beneficial than previously thought, particularly regarding building endurance/fatigue resistance.

In addition, high-intensity training, while necessary to increase VO2 max, improve running economy, and strengthen the aerobic system, is stressful on the body and likely to impede progress if done in large amounts.

In any regard, as the evidence shows an 80/20 plan is the optimal ratio for those runners hoping for faster times and improved overall running performance, it is certainly worth considering.

Fitzgerald notes that Seiler’s research is so compelling it should serve to “remove the guesswork from the training process” even for non-elite runners and make running “a simple matter of planning your workouts in accordance with the rule and monitoring your running intensity during each work out to ensure you’re where you’re supposed to be.”

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What Do We Mean by “Hard” Running and “Slow” Running?

Of course, while following the 80/20 Rule may seem simple, it requires an understanding of what “hard,” or high-intensity, running is and what “slow,” or low-intensity, running is.

According to Fitzgerald, low-intensity running is running below the ventilatory threshold, which is the point when “your breathing becomes labored” and you feel as if you cannot “draw in as much air your body wants.”

There are several ways to measure running intensity and find your ventilatory threshold, but Fitzgerald notes the most practical methods involve relying on:

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Perceived Effort

Perceived effort, or the rate of perceived exertion (RPE), is simply your subjective assessment of how hard you feel you’re working.

This assessment can be quantified by using a scale of 1 to 10, with 1 being minimum effort, such as a gentle stroll you feel you could maintain forever, and 10 being, essentially, a full sprint you could not sustain for more than about 30 seconds.

In this context, low intensity is considered to fall within the 1 to 4 levels, moderate intensity is levels 5 and 6, and high intensity is levels 7 through 10.


Heart Rate

Heart rate involves more variables, but it’s important to determine your heart rate at your lactate threshold for simplified purposes. This threshold metric marks the upper end of the moderate-intensity range and corresponds to an RPE of 6.

To determine your lactate threshold heart rate, Fitzgerald suggests running a 30 minute time trial while wearing a heart rate monitor and averaging your heart rate over the final ten minutes.

Alternatively, he suggests simply noting your heart rate while running at an RPE of 6 or when talking is slightly uncomfortable.

You can also calculate your heart rate training zones by performing a maximum heart rate test.

Zones can vary depending on the method you are using. For example, Garmin zones are as follows: zone 1 and zone 2 are the lower intensity zones, zone 3 is moderate intensity, and zones 4 and 5 are high intensity zones.


Pace is a measure of how fast you run a specific distance. To determine your intensity in terms of pace, Fitzgerald suggests you note your pace when running at different RPEs (or heart rates, if you have that information).

Another option is to input a recent race time into an online pace calculator, such as the one created by Greg McMillan.

Recovery Run Pace and Long Run/Easy Pace indicate low-intensity running, Tempo Run Pace corresponds with moderate-intensity running, and Speed Pace or Sprint Pace represents high-intensity running.

Once you have a reasonable idea of what constitutes low intensity, moderate intensity, and high intensity, you can begin to incorporate the 80/20 Rule, or at least some version of the “mostly easy days” training theory, into your own running plan.

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How Do I Implement The 80/20 Running Principle Into My Training Schedule?

Fitzgerald emphasizes that the 80/20 ratio is an approximation and that runners should not worry about being a little off one way or the other.

Rather, he suggests designing a training plan that divides easy and hard runs (including runs done at both moderate and hard intensity) within close range of an 80/20 ratio.

Of course, even hard workouts involve some segments of easy running, either as part of the warm-up or cool-down or during the recovery segments during interval sessions, so a more accurate way to achieve an 80/20 balance is to determine your total weekly mileage and run no more than 20 percent of that mileage at a moderate or hard intensity.

You can base your 80/20 calculations on either time spent running, or miles run, it’s up to you!

How Can I Adpat My Current Running Plan?

If you’re like most runners, you’re probably looking at these numbers and realizing that you run more than 20 percent of your run training at a moderate or high intensity.

According to Fitzgerald, research shows that recreationally competitive runners typically run more than half their miles at a moderate or high intensity, so you’re not alone if your current training program is far from this ideal.

Given the extensive research showing that limiting your harder running to no more than 20 percent of your total miles is the ratio most likely to lead to improvement, it makes sense to try and see what it can do for you.

It’s also important to remember that the hard 20 percent of runs can be done in various ways, including longer sustained tempo runs, hill running, or repeats of short, fast intervals.

The key to this type of running does not lie in any specific running plan, merely the overall percentage of intensities, so there is room to create a plan that makes sense for you.

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As with any plan, of course, there are some caveats:

Are There Instances When The 80/20 Plan Doesn’t Work?

#1. Individual Differences

Some people respond better to a slightly different ratio of hard and easy running, so pay attention to how you progress with this training and feel confident that some minor tweaking of this ratio is fine if it seems to suit you.

#2. Training Cycle Adjustments

It may be optimal to alter the ratio during certain periods of a training cycle.

During an initial, or base phase, when you are simply trying to develop or maintain a running habit and increase mileage, low-intensity running can make up more than 80 percent of your total running.

Conversely, during a taper phase (a one—or two-week period of decreased running prior to a significant race), while the overall mileage will decrease, the percentage of harder running may increase somewhat.

Fitzgerald notes that research shows the best way to “rest and prime the body for racing” is to “sharply reduce the overall training volume while continuing to do high-intensity workouts.”

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#3. When Training For Shorter/Faster Races

While moderate-intensity and high-intensity running are lumped together for 80/20 running, evidence suggests that when training for longer endurance events, runners may see more improvement with a focus on moderate-intensity running.

Those aiming for shorter, faster races may benefit from emphasizing high-intensity running in their 20 percent.

#4. After A Break In Training

If you have been ill, injured, or otherwise sidelined for a while, you may want to minimize the harder running.

Should You Try The “Mostly Slow” Approach?

If you think you’re running more than 20 percent of your miles at a moderate or high intensity, feel like you are in a rut, and are curious about the idea of running slower to get faster, then get out there and run—just keep it mostly slow!

If you are doing half-marathon or full marathon training, you surely have long runs worked into your training plan. Here are some ways to spice up those critical efforts:


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A lifelong runner and USATF Level 1 coach of high school cross country and track, Sarah enjoys racing all distances, from the mile to ultras. She is a recent transplant from California to Seattle and spends her free time exploring her new neighborhoods by foot.

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