Ever heard the advice to run slower if you want to become a faster runner? I hope you didn’t shrug it off as non-sense because the person who developed this unique training methodology is widely considered to be among the best endurance athletes and coaches.

Phil Maffetone’s approach aims to help you run faster by running slowly more often. Instead of aimlessly speeding through your workouts, Phil teaches precise cues to look out for trusting that his system will do its magic. And believe it or not, most books I read about endurance, which themselves were mediocre at best, referred to Maffetone’s book as the first port of call if you want to build endurance.

How can an athlete improve their endurance?

There’s 4 things you need to focus on if you want to be a successful endurance athlete, according to Phil:

  1. Build a great aerobic base. What he means is that you need to rewire your physiology to burn more body fat for fuel (as opposed to using glycogen from your liver). Because you store many times more fat than glycogen, you can produce bigger amounts of energy by burning fat. This is achieved by training in specific HR zones.
  2. Eat well. For an endurance athlete this means no processed sugar, a restricted intake of carbohydrates with allowance for only complex carbohydrates, and a higher fat intake since your body will be using body fat (fatty acids) much better.
  3. Reduce stress. You need to manage your physical and mental stress. Without an eye on them, you won’t improve as they’re detrimental to training. Phil puts it simply as: Training = Work + Rest.
  4. Improve brain function. The brain and your nervous system control all of your activities. Your running performance almost always comes down to how bad you want it. Luckily, you can train yourself to push further in your endurance training. Aside from mind tricks like distraction, you can try a specific set of brain training patterns – if interested see Matt Fitzgerald’s Brain Training For Runners.

Now, number one here is by far the most important. Why?

Because mastering your aerobic base will help with the other three: by training at aerobic base you will burn more fat than sugar and due to the lower intensity of your training the stress response will also be lower. Furthermore, your brain exposed to long, slow runs will adapt to endure and push further.

The best thing about Maffetone’s method is that you’ll come to run much faster at the same effort / HR. As long as you’re doing it right, your performance will keep improving.


(Re)building your endurance base

Compared to just a few months ago, my tempo run is now faster by a minute per mile. Big change, especially for an advanced runner. The only change I made to my training in that time was to focus on rebuilding my aerobic capacity in order to have a solid endurance base.

Based on the Maffetone method, this involves:

  1. Putting your ego to the side. You will need to train much slower than you’re used to. Meaning that majority of your runs on Strava will look like you’re having a laugh, rather than seriously prepping for the next OCR.
  2. Getting a GPS watch with HR monitor/strap. 
  3. Calculating your maximum aerobic training heart rate. About 80% of your runs will be at certain aerobic heart rate zones. To determine these zones, you need to discover what your max aerobic heart rate is. To calculate it:
    A. Subtract your age from 180: 180 – age = max. For example, 180 – 27 = 153.
    B. Modify this number by selecting among following categories, that describe your condition best:
    – If you’re recovering from major illness (heart disease, operations, regular medication etc.) subtract 10. For example, 153 – 10 = 143.
    – If you’re injured, have alergies or asthma, or you’re just getting back into training, subtract 5.
    – If you’ve been training consistently for the past two years (at least 4 times a week), keep the number the same (180-age).
    – If you’ve been training consistently for more than two years without injuries and are at a level where you could compete with other athletes, add 5.

So for example, if you are:

  • 30 year old male or female
  • Who has been training for the past 2 years with some minor injuries here and there

Then your aerobic maximum heart rate would be: 180 – 30 – 0 = 150. Here 150 is the heart rate which you shouldn’t exceed while doing most of your (aerobic) runs.


Using your aerobic maximum heart rate

Now that you have your max aerobic HR, it’s time to apply it to your running routine.

You should be using your maximum heart rate (i.e. not exceeding it) on any of your aerobic runs:

  • Your easy and recovery runs
  • Long slow distance runs
  • Any other runs that are aerobic (not tempo, sprints or other high-effort runs)

As with any other endurance training methodology, Phil also advises to keep your fast and anaerobic runs to the minimum. The majority of endurance athletes spend 80% of their training time on aerobic runs, using the remaining time for hills, interval and speed work.

For best race results, I’d recommend increasing your share of faster runs leading up to d-day. In this way you will have a strong aerobic base off of which you can then build speed.


Tracking improvements

Phil Maffetone calls it the MAF test: a breakdown of your aerobic run per mile which you should do every few weeks to assess how you’re improving.

Choose your location and run it at or below your aerobic maximum heart rate. Then document your mile splits.

Here’s an example test:

Week 1 MAF test:

  • Mile 1: 12:10
  • Mile 2: 12:20
  • Mile 3: 12:34
  • Mile 4: 12:45

After a few weeks of rebuilding the base, your progress might look like this:

Week 6 MAF test:

  • Mile 1: 10:20
  • Mile 2: 10:30
  • Mile 3: 10:23
  • Mile 4: 11:03

This is just a fictional example, but as you can see for the same heart rate your aerobic time would increase and you could shave minutes off your per-mile time. Note that this does not translate directly into tempo or race pace runs, however you will experience major improvements there too.


As with any training plan, you need to stay consistent and patient. Allow your body to adjust and improve slowly. It will be hard to restrict yourself to run at that slower pace at first. Eventually you will feel better with every run: your body will learn to use fat for fuel better, and as long as you eat well your body adapt better to the racing conditions. And the mind too – you’ll learn to persevere and endure better. Finally, your recovery will be enhanced, since you won’t be bashing your soft tissues as well as the entire nervous system on every run.

If you want the best outcomes from your training, I recommend picking up Maffetone’s Big book of endurance training and racing – it’s a goldmine of knowledge.


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