In the spring of 2020, I was beginning to build my mileage for a fall ultramarathon.
I had tried to build my mileage up in the past but found myself nursing injuries after spending a few weeks above 50 miles.
Doing some research on different training for marathons and ultramarathons, I came across Phil Maffetone and the MAF Method of training.
I remember reading about it and thinking that the MAF Method was perfect training for an ultramarathon.
I began a 7-8 month experiment using the MAF Method to train myself for a 50-mile race.
When I brought up the MAF method to others and described how it focussed on low-intensity running workouts, they always had questions about what it was and how it worked.
In this article we will answer these questions:
- What is the Maffetone Method of Moderate Running?
- How do you train using the Maffetone Method?
- What heart rate should I be training at?
- What are the MAF tests?
- Are MAF tests a good indicator of performance?
- Can you get faster with no anaerobic training?
- Should I try the Maffetone Method?
Also, I will discuss my experience using the Maffetone Method of Moderate Running for training.

What is the Maffetone Method of Moderate Running (MAF Method)?
The Maffetone Method of Moderate running is a method of training that uses your heart rate to ensure you are staying aerobic on your runs.
It was developed and is named after Dr. Phil Maffetone.
Dr. Maffetone is a doctor and a coach. He has worked with professional athletes across a wide variety of sports including runners and triathletes.He has coached Mark Allen, the six-time Hawaii Ironman Triathlon Champion.
As Mark states:
“The point is not to see how fast your body can move. The point is to change the way your body gets energy. You want to burn more fat and less sugar.”
The Maffetone Method of Moderate running is about slowing your runs down so that you stay aerobic. When your body is below its aerobic threshold it will burn fat instead of sugar.
Your body has a lot more fat to burn than it does sugar.
When your body is burning sugar and its fuel source runs out, we bonk. This is what is happening when marathoners hit “the wall”.

How do you train using the MAF Method?
The Maffetone Method is training using your heart rate.
You perform all your runs while keeping your heart rate below a certain threshold.
This can mean that your pace will decrease significantly from what you normally run.
Many runners complain about how slow the pace is when they try to stay under their MAF heart rate.
I was used to running around 8:00-8:30 pace on most of my runs.
When I started the Maffetone Method, I had to slow down to 9:30-10:00 pace to keep my heart rate below the threshold.
What heart rate should I be training at?
The heart rate you should be training at is an exact number determined using The MAF 180 Formula.
Dr. Maffetone breaks down the formula in his article: Want Speed? Slow Down!
Here it is:
The MAF 180 Formula
To find your maximum aerobic heart rate:
Subtract your age from 180 (180 – age).
Then modify this number by selecting a category below that best matches your health profile:
a. If you have, or are recovering from, a major illness (heart disease, high blood pressure, any operation or hospital stay, etc.) or you are taking medication, subtract an additional 10.
b. If you have not exercised before or have been training inconsistently or injured, have not recently progressed in training or competition, or if you get more than two colds or bouts of flu per year, or have allergies, subtract an additional 5.
c. If you’ve been exercising regularly (at least four times weekly) for up to two years without any of the problems listed in a or b, keep the number (180 – age) the same.
d. If you have been competing for more than two years duration without any of the problems listed above, and have improved in competition without injury, add 5.
For example, if you are 30 years old and fit into category b:
180 – 30 = 150, then 150 – 5 = 145.
When training, you want to keep the heart rate within 10 BPM of the max heart rate, but not exceed it.
For example, if your max aerobic heart rate is 150, you will want to keep your BPM between 140-150 for your run.
Related: Why Is My Heart Rate High On Easy Runs? 8 Reasons + Solutions

What are the MAF tests?
The MAF test is a key component of the MAF Method of Moderate running. Dr. Maffetone explains:
“A significant benefit of aerobic base building is the ability to run faster at the same effort, that is, at the same heart rate. A heart monitor can help objectively measure these improvements using a test I developed in the mid-1980s called the maximum aerobic function (MAF) test.”
The MAF test is done by running 5 miles continuously on a track at your maximum aerobic heart rate. You should do a proper warmup before the test.
Doing the test on a track eliminates variables such as hills and allows you to have the same course each time.
As you run each mile of the test, your time will likely slow. This is natural.
Dr. Maffetone says you should run this test once a month to see how you are improving.
Your average pace should increase each month as you become fitter. If your time is not improving, it may indicate an oncoming injury.
I ran a MAF test every month between May and November 2020. Here is a breakdown of my average pace:
Month | Pace |
May | 9:22 |
June | 8:48 |
July | 8:50 |
August | 8:58 |
September | 8:11 |
October | 7:37 |
November | 7:11 |

A few things I would like to point out:
I did no dedicated speedwork. I had a few runs where I felt good and pushed the pace to a tempo, but that was it.
I was doing some bodyweight exercises and strides occasionally, but not consistently.
My times increased in July and August because of the summer heat. July was in Louisiana (after a 13 hour drive the day before) and August was in North Carolina (I marked humid in my log for that day).
As you can see, my average time for 5 miles dropped over the course of the 7 months.
Are MAF tests a good indicator of performance?

According to Dr. Maffetone, the MAF test can be used to predict your running performance.
In his article, he provides a table of MAF tests to race time. These were gathered from actual runners he coached over several years:
MAF Min/Mile | 5K Race Pace | 5K Time |
10:00 | 7:30 | 23:18 |
9:00 | 7:00 | 21:45 |
8:30 | 6:45 | 20:58 |
8:00 | 6:30 | 20:12 |
7:30 | 6:00 | 18:38 |
7:00 | 5:30 | 17:05 |
6:30 | 5:15 | 16:19 |
6:00 | 5:00 | 15:32 |
5:45 | 4:45 | 14:45 |
5:30 | 4:30 | 13:59 |
5:15 | 4:20 | 13:28 |
5:00 | 4:15 | 13:12 |
With this table, Dr. Maffetone explains:
The above runners included those who developed an aerobic base and raced on a flat, certified road course or track.
Most did not perform any anaerobic training, and for most, this was their first competition of the spring or fall racing season.
Moreover, 76% of these athletes ran a personal best time for this distance! Similar relationships exist for longer events and for other sports.

So does it work?
Speaking for myself, I don’t think this table held up at all. My last two MAF Tests were at 7:37 pace and 7:11 pace.
According to the table, I should have been able to run a low 18 minute 5k.
I did run a 7-mile race at the end of October in 49:08, or just over 7-minute pace. I would not have been able to shave off over a minute from my pace for a 5k.
Can you get faster with no anaerobic training?
As you can see from my MAF tests, I was getting faster without doing anaerobic training. But, I feel that there was a limit to this.
In the last two MAF tests I ran, my opening miles were below 7-minute pace. I felt fine at this pace aerobically, but my legs felt red-lined. I wasn’t used to running at that pace and my legs couldn’t go any faster.
If you were to look at the training of any competitive runner, from high school athlete to Olympic Gold Medalist, you would find anaerobic runs in their training.
There is a reason why distance runners do anaerobic workouts: they work!
They will make you a faster and better runner.

Should I try the MAF Method?
For me, the Maffetone Method of Moderate Running was a training tool that did what I needed it to. It allowed me to build my mileage and train for a 50-mile race.
It is suited for those who are in a base phase and want to build miles and stay aerobic on their runs.
I do think there are limits to what it can do. At some point in your training, you will need to add anaerobic workouts.
This is true for milers or marathoners.
Whether or not you try the Maffetone Method of Moderate Running will depend on you and your goals.
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