What is the 80/20 rule?

There are a lot of different training modalities out there, but the 80/20 rule is easily one of the most popular. This rule states that 80 per cent of your weekly training should be done at a low to moderate intensity, and about 20 per cent at moderate to high intensity. It’s a rule that’s followed by nearly all elite runners, cyclists, swimmers, triathletes and other endurance athletes around the world, and so it has unsurprisingly been adopted by many recreational athletes who are looking to improve their times. But how do you determine running intensity? What does 80 per cent of your training volume actually look like? Does the 80/20 rule apply to lower-mileage runners? We answer all these questions and more to clear things up so you can effectively apply the rule to your own training.

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How much is 80 per cent?

Many runners might think they’re doing 80 per cent of their training at a low to moderate intensity, but most of them probably aren’t. In reality, the average recreational competitive runner is likely running about a 50/50 split. The reason for this is two-fold, with many runners not being fully aware of what an easy or moderate pace actually is (more on that later), and also not truly paying attention to their weekly running volume and calculating accordingly.

To calculate 80 per cent of your running volume, you first need to know how much you’re actually running in a week, which you can do based on the number of kilometres you run, or how many hours you spend running. For example, if you’re running 50K per week, 80 per cent of that volume is 40K. That means that in one week, you should be running 40K at an easier pace, and only 10K should be spent running at a higher intensity. If you prefer to track your running volume by time, if you spend five hours per week running, 4 hours of that time should be easy running and only one hour should be higher intensity.

Of course, that doesn’t mean that you’re going to run easy for an hour per day for four days, then on the fifth day you’re going to crank out a 60-minute time trial. More likely, you’re going to pick two days out of your week where you spend 30 minutes of your run at a higher intensity, with 15 minutes of warmup and cooldown running on either side. Here are a couple of examples.

Warmup: 15 minutes easy
Workout: 30-minute progression run
Cool Down: 15 minutes easy

Warmup: 15 minutes easy
Workout: 4 x 5 minutes hard with 2 minutes easy jog recovery
Cooldown: 10-15 minutes easy

How do you determine intensity?

This is not quite as simple as calculating running volume, and is where many runners get off-track. Why? Because without realizing it, you’re likely running your easy mileage at a much faster pace than you need to, or should.

Matt Fitzgerald of 80/20 Endurance breaks running intensity into seven zones: Zone 1, Zone 2, Zone X, Zone 3, Zone Y, Zone 4 and Zone 5. Zone 1 is the lowest intensity, which requires you to actively hold yourself back to stay on-pace, or is used during a recovery jog after a hard workout. Zone 2 is much broader, and is likely where you’ll do most of your easy runs. It will vary depending on how you’re feeling that day.

Zone 3 is a relaxed effort, which some runners might call comfortably hard. You shouldn’t be straining to maintain this pace. Zone 4 is a little trickier to get right, but you could equate it to half-marathon pace, and Zone 5 is for hard interval or hill workouts. Both Zone X and Zone Y are not given a number because they represent in-between paces, which Fitzgerald explains only exist as gaps between other zones. This prevents low-intensity efforts from bleeding into moderate-intensity, and on the upper end forces athletes to commit to higher-intensity running.

Fitzgerald explains that you can measure running intensity based on pace, heart rate, and power, and provides testing protocols for all three. One simple way to do so is to enter a recent race result into the 80/20 zone pace calculator, which will give you target pace ranges for each of the zones. As you improve, it is important that you continue to update the calculator to reflect your level of fitness.

Does the 80/20 rule apply to lower-mileage runners?

As we mentioned, nearly every elite endurance athlete trains using the 80/20 principle, but does it make sense for a more recreational athlete to do the same? An elite distance runner, for example, might spend 15 hours per week running, which means that they’re spending three hours each week running at a higher intensity. That amount of high-intensity running will certainly have a significant training effect. By contrast, if a recreational runner spends four hours per week easy running and only one hour at a higher intensity, are they getting the same benefit?

One 2013 study found that it does. Researchers split a group of 30 recreational runners with 10K times just under 40 minutes into two groups: each ran just under 50K per week, but one followed the 80/20 principle and the other did 50/50. After 10 weeks, the 80/20 group had improved on their pre-study 10K time by an average of five per cent (about a 35-second improvement), while the 50/50 group only improved by 3.6 per cent. The researchers also noted that the runners who did the best job of adhering to the 80/20 rule improved by seven per cent, which is a 47-second PB.

So yes, even if you’re not running the same volume as an elite runner, the 80/20 rule can still work for you. Even individuals who only manage to run two days per week can use this method, provided each run includes a mixture of easy and hard running, while still adhering to the 80/20 split.

Should everyone follow the 80/20 rule?

While this style of training does seem to work well for the majority of runners, it is, of course, not the only path to success. Every runner is different, and what works for someone else might not be as effective for you. The great thing about the 80/20 method is that if you follow it properly, it can go a long way in preventing you from overtraining, since it heavily controls how much hard running you’re doing. It is also highly adaptable, allowing you to split up that 20 per cent of hard running in any number of ways. If you’re really serious about improving your performance, consider getting a coach or following an 80/20 training plan for your next goal race.

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