One of my athletes inspired this post this week. Her name rhymes with Fahra. 😝

Polarized training is a pretty established concept in the world of endurance sport. It’s when you do >80% of your training at low-intensity and up to 20% at high-intensity. Many studies have found that this approach delivers a greater performance benefit vs training at moderate intensity.

Here are some of the reasons why it works:

• Running easy on easy days allows you to run your hard days hard. After an easy run, you should feel so good that you can’t wait to do your next hard workout.
• Your muscles experience microtears when they do a hard workout. Rest and recovery is when they get rebuilt. Constantly subjecting your muscles to microtears without adequate recovery will increase your risk of injury.
• Running slow builds aerobic fitness. Running fast builds anaerobic fitness. By running in the “grey zone”, it’s too slow to build your anaerobic fitness but it’s also too fast to build aerobic fitness or promote recovery. You end up doing neither.

Despite the proven research and the popularity of this approach, many runners don’t follow this in their training.

Why is it so hard to run easy?

Many of us are guilty of running too hard on our easy days. Here are some reasons that cause us to fall into this trap:

• Most runners don’t even know what their easy pace should be. Easy pace is much slower than you think. Chances are, you may not even realize you are running in the grey zone.
• Runners are celebrated for running fast. You are more likely to get comments like “Wow, great pace!” when you post a fast run on Strava.
• Running slow feels like you’re not doing as much work.
• Seeing slower paces can be discouraging or may make you wonder whether slow running will actually help you run faster.
• It can be harder to run slow if you are used to running at your natural pace.

If you want to run fast, you have to run slow. Here are some ways to determine your easy pace:

• On the Rate of Perceived Exertion (RPE) scale, your easy pace should be 3-4/10.
• Based on heart rate zones, you should be in Zone 2 (less than 70% of your max HR or less than 90% of your lactate threshold heartrate).
• Based on pace, an easy pace should be 45-60 seconds/km slower than your half marathon race pace. For example, if you are able to run a half marathon in 2 hours (5:42min/km), your easy pace should be ~6:30min/km. Please note, there are many other factors that can impact pace (e.g. terrain, weather, stress, etc…) but the key takeaway is that your easy pace should be MUCH slower than your race pace.
• My favourite way to determine your easy pace is to sing a song while running. Try singing Happy Birthday or the ABCs the next time you are out on an easy run. It’s not that easy! The good news? Just like anything, you can do it if you practice.

Keep your easy days easy and your hard days hard. The 80/20 Method by Matt Fitzgerald is a great resource if you want to learn more!