I realize that I'm such a devotee of MAF that a separate blog post about why is going to be necessary. I'll put that in my backlog.
In the meantime, I had a conversation with some friends recently that made me realize why MAF is such an important discipline to follow for most runners. The conversation followed this format:
- I mention to people that I run marathons (I don't lead with that fact or anything, but sometimes it comes up).
- The people I'm chatting with respond with something to the effect of, "I can barely run X."
- I always try to respond by saying that marathons are not something that most people want to do, so it really shouldn't be any different from any other skill that people have.
This conversation format has happened many times to me in the past. As a result, it occurred to me that, the fact that most people almost always respond to the marathon discussion with their own experience, makes me think that it IS different, at least a little bit, from other skills. My hypothesis is that, while many people have no desire to run marathons, on a deeper level they recognize that running is something that they can do in some capacity. Upon hearing that someone can do it for an extended time, it elicits such a response. (if you think differently, I'd love to hear why)
So why does MAF matter? Before I answer that, there is a bit of background. As I said, everyone CAN run; in other words, they have the ability to move faster with their feet than they usually do when they're motivated to do so. The problem, though, is that when they DO run as part of a running regimen, they assume that running is just running and that they can pick it up from where they left off. "I've run before, so I know how to run!" The problem is that this is not really true the longer you have gone without running.
As you get further away from aerobic fitness in general and running in particular, the structures that support running, including cardiovascular, musculoskeletal, and neurological mechanisms, are out of practice. The main indicator that people use to identify when they are at their limit is their cardiovascular system (most likely the burning in their lungs), and it is likely that one's cardiovascular system will provide feedback well after they should. In other words, your ligaments and tendons may be straining well before your lungs; you just don't know it.
So here is where MAF is really important. As a reminder, MAF is a formula created by Dr. Phil Maffetone that says that your maximum aerobic function (MAF) is roughly 180 beats per minute minus your age. For me (a 39-year-old), that's 141 beats per minute.
The key piece of information that I learned from a recent podcast on Endurance Planet that seemed to even catch the host Tawnee Prazak by surprise is that Dr. Maffetone arrived at the MAF heart rate when he would see a runner's form break down.
As you improve your aerobic base (which encompasses all of the systems noted above that feed into your running form), your heart rate at a specific pace decreases because, essentially, your ability to maintain your form improves. When you first begin running after a long hiatus, your heart rate may be high at a painfully slow pace because all the components that allow you to move are not very efficient, and your heart has to work harder to enable them to keep the pace that your brain is dictating. Most people may look at their pace and find themselves frustrated. "I'm not even running and my heart rate is already at MAF!" As a result, they may ignore their MAF pace and blow right past it, even though their form may suffer. Again, they assume that, since they used to be able to run, that they can do so again. The issue is that this invites opportunity for injury.
So ultimately, because everyone knew how to run at one point, many believe that can pick up where they left off, but in reality, just as with any other skill, you have to return to a pace that your body can support. The example that I think of is with the piano. When I was younger, I played the piano regularly. I never got to the point at which I could simply sit down and play a song I had never seen before. So I would start a song slowly to ensure that I got the fingering correct before I sped up. The difference between piano and running, though, is that with piano, you can hear your mistakes immediately that tell you that you need to slow down. With running, you have no visual or aural feedback mechanism DURING the run that tells you that you need to slow down.
Your MAF heart rate is that feedback mechanism, and that's why I believe that it's so critical.
The good news? Just like almost any other skill, you make a ton of progress initially if you allow yourself to progress slowly. So if you stay at MAF early on, chances are good you'll see improvements over the first several months, and you'll be running more quickly in no time.
Best of luck out there!