There is a training method that elite runners have been using for years, and it goes against what most recreational runners actually do. It is called polarized training, also known as the 80/20 method. The premise is simple: around 80 percent of your running should be easy, and around 20 percent should be genuinely hard. The vast middle ground, the moderate effort that most runners default to, barely features at all.
If you have ever finished a run feeling like you worked reasonably hard but not particularly fast, you have probably spent time in that middle zone. It feels productive. It is not easy, so it registers as training. But research suggests it may be one of the least effective places to spend your running time.
What the 80/20 rule actually means
The polarized training model divides effort into three zones. Zone 1 is easy, conversational pace. Zone 3 is hard, where you are working near your limits. Zone 2 is everything in between.
The 80/20 rule says your training should be split roughly 80 percent in Zone 1 and 20 percent in Zone 3. Zone 2, that moderate, somewhat uncomfortable but sustainable effort, gets almost none of your time.
This was popularised by Dr. Stephen Seiler, a sports scientist who studied elite endurance athletes across rowing, cross-country skiing, cycling, and running. What he found was consistent: the best athletes did not train moderately most of the time. They trained very easy or very hard, with little in between.
That pattern is now getting attention from recreational runners too, partly because coaches like the Norwegian Method's architects have made the idea mainstream, and partly because the research holds up when applied to non-elite training.
Why the moderate zone is a problem
The moderate zone is seductive because it feels like effort. You are breathing hard enough to notice, your pace is decent, and you finish the run feeling like you did something. The problem is that running in this zone produces fatigue without the same training adaptations as either easy running or hard running.
Easy running, done at genuinely low intensity, builds aerobic base, improves fat utilisation, and allows your body to recover while still accumulating volume. This is essentially what Zone 2 training for runners is about, and it is the foundation most runners underinvest in.
Hard running, done at high intensity through interval sessions, tempo efforts, or threshold work, creates the stress stimulus your body adapts to. It pushes your VO2 max and raises your lactate threshold.
Moderate-zone running delivers neither benefit cleanly. It is hard enough to add to your fatigue load, but not hard enough to drive the adaptations you want. Coaches sometimes call these "junk miles", though the reality is more nuanced: the problem is not moderate-intensity running in isolation, it is the habit of always running there.
How to actually apply it
The practical version of polarized training is less complicated than it sounds. If you run four or five times a week, roughly three or four of those sessions should be genuinely easy, and one should be genuinely hard.
Easy means easy. Most runners go too fast on their easy runs. A useful guide: you should be able to hold a full conversation at easy pace. If you are breathing through your nose comfortably, you are in the right zone. If you need to pause mid-sentence, you are too fast. Many runners find this humbling at first. Easy pace can feel embarrassingly slow, particularly if you are used to running every session at something resembling race effort.
Hard means hard. Your high-intensity session should be genuinely uncomfortable. Intervals, hill repeats, or a proper tempo block all count. The key is that you feel the difference between this session and the rest of your week.
If you are new to structured training and wondering how many days a week to run, the polarized model works well across volumes. Four days a week might look like three easy runs and one quality session. Six days a week might be five easy and one or two quality efforts.
One thing worth tracking: your running economy tends to improve over time when you commit to polarized training, particularly if you were previously spending a lot of time in the moderate zone. The easy runs build efficiency, and the hard sessions raise your ceiling.
Gear that helps
Polarized training involves a lot of outdoor easy running, often in the early morning or late afternoon when the light is variable. A few pieces of gear make a real difference.
A GPS watch with heart rate monitoring lets you keep honest about your easy pace. Without data, most runners drift too fast on easy days. Any watch that shows your heart rate or pace in real time will help you stay in the right zone.
Good running shoes for easy days do not have to be your race shoes. Many runners keep a rotation, using a more cushioned, forgiving shoe for easy volume and a firmer, lighter shoe for quality sessions. A shoe rotation also extends the life of each pair.
Sunglasses matter more on easy days than most runners realise. Easy runs tend to be longer, which means more time outdoors and more UV exposure. Sunglasses that adjust to changing light are useful here. The Re. Adaptor lens is photochromic, meaning it darkens in bright conditions and goes near-clear in low light, so it works across the full range of a long morning run without you having to swap lenses or run blind in shade. All Re. lenses are UV400 and built not to bounce, which matters when you are out for 60 to 90 minutes at easy pace. You can see the full range at reyourrun.com.au.
A running vest or belt for hydration rounds out the gear list on longer easy sessions. Easy pace does not mean easy on your body when the session runs past an hour.
What to realistically expect
Switching to polarized training takes adjustment. Your easy runs will probably feel slower than you are used to, and that is the point. Give it four to six weeks before judging the results. The aerobic base you build through genuine easy volume takes time to show up in your performance.
The quality sessions may feel harder than your current training too, because you are better rested going into them. That is also the point. The contrast between easy and hard is what makes the method work.
Most runners who commit to the 80/20 split report that their quality sessions improve, their recovery between sessions feels better, and their race performances eventually follow. It is a slower path than chasing every run, but it tends to be a more sustainable one.
Where to start
The simplest version: slow down your easy runs this week. Do not change anything else yet. Just take your next three runs at a pace where you can hold a full conversation, and see how it feels.
Once easy pace becomes natural, add one proper quality session per week, such as a set of intervals or a tempo block. Track your effort distribution over a month and see where you land.
If you want to understand the lens side of outdoor training better, the Re. Lens Guide covers what different lenses do and when to use each one. And if you are putting together your training kit, our frames page shows how the four Re. frame options compare.
Polarized training is not a secret. Elite runners have been doing it for decades. The shift is runners at every level starting to take it seriously, and realising that most of their hard work might be better spent going easy.
Tim Golubev
Founder, Re. (Re Your Run)
Tim built Re. after years of running in sunglasses that bounced, fogged, and ended up on his forehead. After discovering the UV damage that builds up without eye protection (even on cloudy days) and hearing the same frustrations from hundreds of other runners, he decided it was a problem worth fixing properly. With a background in Product across multiple industries, he approached it like any product problem: figure out what's broken, then build something that actually fixes it. He runs daily, co-founded Rose Bay Run Club, and Re. is his attempt to make one less thing that gets in the way of a good run.
