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Run Slow to Run Fast: How to Use the 80/20 Rule in Running

More and more runners have begun using a bit of an unconventional training method: run slow to run fast.

Whether for a PR or simply personal improvement, runners are often trying to increase their speed. Between speed workouts, form tweaks and increased mileage, there are tons of strategies for running faster.

But could the secret really be something as simple as running slower during training?

Can running slow make you faster?

A great deal of elite runners and professional coaches subscribe to training that involves running slower than their goal pace a majority of the time. What they are finding is that running slow during training actually does make you faster on race day.

Why does running slow make you faster?

Running slow” can mean different things to different people, but the term always refers to aerobic running. This type of running involves running at less than 80% of your maximum heart rate. In this state, your body is using oxygen to convert glycogen to fuel your muscles, which can be sustained for much longer than anaerobic running.

Related: Running Heart Rate Zones | A Guide to Heart Rate Training

The reason running slow during training can result in running fast on race day is because this slow pace allows your body to improve its aerobic energy system.

The time spent running at a slow pace helps your body increase the rate at which it converts oxygen to glycogen for fuel. As your body gets more efficient at creating energy, it builds endurance to run harder without fatigue.

When too much of training is spent running anaerobically, runners get stuck in middle ground. Their bodies are unable to increase their aerobic energy system which results in “slow” paces that feel extra challenging.

What is the 80/20 rule in running?

In order to avoid running too fast on easy days, many subscribe to the 80 20 rule in running. The 80/20 rule simply means that 80% of training runs are completed at a slow, easy pace, and only 20% at a harder effort.

If you are wanting try “run slow to run fast”, the 80/20 rule can help structure your training. Completing 80% of your training runs at a slow pace leaves a small percentage of time for speed workouts or race pace miles.

Aim to keep your easy runs easy and your hard runs hard. However, even with this in mind, many runners find that it is surprisingly difficult to run slow this often. Challenging yourself to run slow in order to run fast might be more difficult than you expect, but will certainly pay off on race day.

The run slow to run fast method can help increase running speed without risking injury. Here’s how to use the 80/20 rule to run faster on race day while running slower in training! #runslowtorunfast

Why You Should Run Slow to Run Fast

In case you’re not already convinced, here are a few reasons you should consider running slow to run faster – besides just increasing speed.

Improve aerobic energy system

When running in the aerobic zone, the body uses oxygen to convert glycogen to fuel and energy for the muscles. Increased time running in this zone allows the body to develop a higher mitochondrial density and increase aerobic enzymes.

This then translates to an increase in aerobic energy production, helping build endurance for long runs and harder efforts. The more time spent running slow, or in the aerobic zone, the more time the body has to improve its aerobic energy system.

Less risk of injury

Running slowly, or at a lower intensity, means that there is less strain placed on the muscles and less physical effort required. This in turn helps reduce a runner’s risk of injury. The less wear there is on the muscles, bones and joints, the lower the risk of developing an imbalance or injury.

Potential to burn fat as fuel

Running in the aerobic zone means that the body has the potential to burn fat as fuel. If you run slowly for a long enough period of time, your body will eventually deplete its glycogen stores and then turn to fat for fuel. Burning fat for fuel improves the body’s efficiency and also promotes higher calorie burn and weight loss.

Increase resistance to fatigue

A main reason running slow to run fast is successful is because this slow running helps increase the body’s resistance to fatigue. By improving the aerobic energy system, the body is able to sustain activity for longer periods of time, thus decreasing fatigue overall.

Develop cardiovascular and muscular-structural systems

Running slowly requires physical effort without resulting in harmful damage. The sustained physical effort helps strengthen the muscles and cardiovascular system, while avoiding the risk of injury that comes from more intense efforts.

If you’re hoping to try incorporating the 80/20 rule in order to run faster, you’ll need to know exactly what speed to run your easy, slow runs. Running too fast during the easy portion of your training will negate the effects of running slow to run faster.

How fast should a slow run be?

Success with the “run slow to run fast” method comes only if you are doing just that: running slowly. However, most runners differ when it comes to what they consider to be a slow run. Here are a few ways to calculate your slow, or easy, run pace.

Easy Run Pace Calculator

The following are different methods you can use to calculate your easy run pace. Different runners will find different methods more useful depending on how they track their running.

  • 90 – 120 seconds per mile slower than goal pace
  • HR zone 3 (okay to dip into zone 4 – but do not stay there)
  • 60-75% maximum heart rate
  • 115-120% marathon pace

Regardless of whichever method you choose, the pace you calculate will likely be slower than you expect. The key to running slower to run faster is that the slow runs are truly slow enough that your body is not stuck in middle ground.

Slowing down the pace for the majority of training helps runners focus their efforts on those key workouts and long runs. Using the 80 20 rule in running to help guide your training will set you up for success.

Calculating, and sticking with, the easy run pace for slow runs will help you run faster when you are ready to give it your all.

More tips for running slow to run fast:

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