Sunday, 28 September 2014

Maffing About

Ever heard of MAF training? Well I hadn't until about a year ago, when I discovered and read about it. It sounded interesting and I thought maybe I'd give it a try, but then I got injured. A year of resting, walking, jogging and completing the occasional event very slowly. It's been a long road back, and with a lot more to come no doubt. Then, about three weeks ago I covered five miles in just under 40 minutes. Now this may not sound too impressive in the grand scheme of things, but at least it meant that I can now move occasionally at what might generally be accepted as "running" pace. 

The last thing I wanted though was to get back into running too many miles at too fast a pace and get injured again. I needed to take things gently. So I had another look at MAF.

Originally "MAFF" from its inventor Dr Phil Maffetone, MAF is now taken to stand for Maximum Aerobic Function. The theory is that you run lots of miles at a heart rate which is near the top of your aerobic range, but never going into anaerobic. This builds good fat burning and long distance endurance. It also means that you do your training at a relatively slow pace, perfect for my current situation; get the miles in gently.

You determine your aerobic training range first by subtracting your age from 180, for me this is 114. Then Maffetone gives four states, ranging from being virtually inactive to having trained injury-free for five years. I identified with the state of returning from longer term injury, which means I should subtract a further 5. This gives 109, but I rounded up to 110 (I just like easy figures!). The aerobic training range is then from this figure to 10bpm lower, so my range is 100-110 bpm. The theory then is that you should do all your running within this range  -  not as an average, you must be in this range all the time.

I did a bit of research on the net to see how others had got on with this. A general feeling was that most runners felt they were going very slowly and had practically to walk any uphills to keep within the range. They were also frustrated that sessions took much more time using this plan because of the slow pace. Anyway, I dug my HR monitor out of the drawer and got started.

To start with I found it really difficult to maintain the right pace to stay within the limits. I was staggered by the way that the slightest gradient up or down made a significant difference. This really seems to blow out of the water the concept of perceived effort. Running up (or down) an almost imperceptible gradient at the same speed as on the flat seems to take no more or less effort at all, yet the heart rate is very sensitive to it. One parallel I could draw is if you have an instantaneous fuel consumption readout on your car and you go along a motorway at a steady speed, you can see the consumption swing drastically with every slight up or downhill. Height loss or gain clearly has a much bigger impact on energy consumption than we are able to perceive naturally.

But after a few runs I started to get the hang of it, learning how to ease off progressively on slight rises, and speed up on downs. I quickly learned that you have to resist the temptation to compensate too quickly when you see a drift, or you quickly get into an unstable too high/too low heart rate oscillation which then takes time to get out of. I was gradually able to look at the watch less often (at the start it was every 10 seconds or less), and after a couple of weeks I bit the bullet and put the upper and lower alarms on the watch. It's not too bad now (I'm nearing the end of my third week) and on reasonably flat ground I can normally manage half a mile or so before I get a corrective beep. Strange thing is that sometimes I can't tell until I look whether it is a too high or too low warning.

Does it feel very slow? Well, it's clearly slower than normal "steady" running but I can't say that for me it feels excruciatingly slow. Steeper uphills are slow but I haven't been forced to walk yet, and it's surprising how much speed you have to put on to keep above the lower limit on steeper downhills. But I've so far confined myself to gently undulating roads, I'm sure it will get more erratic when I move onto trails with proper hills.

Does it take much too long? That depends on how far you run. If you run at a steady pace (which I guess is what most of us do on most of our training runs), then your heart rate increases gradually over time  -  the well-known phenomenon of "heart rate drift". I can remember that when I was doing more road marathons, my heart rate would go up by about 5bpm for each successive 10k run. But with MAF you don't allow your heart rate to go up so the knock-on effect is that your speed goes down over time. The other thing that effects overall time is the proportion of hilly ground; uphills slow you down and downhills speed you up, but the increase on the downs doesn't seem to compensate the decrease on the ups. I haven't worked out the maths behind that yet but I'm sure there's a reason. So for comparison, this week I have run a relatively flat 5 miles at an average pace of 8.51 (minutes per mile) and an undulating 12 miles at an average of 9.57. So I guess a minute or so per mile slower than I would "normally" run.

Maffetone reckons that if you follow this diligently you should see the speed you can maintain at your aerobic heart rate go up measurably, even over say a three month period. To check this you should perform a "MAF Test" every so often over a repeatable course. He suggests that ideally this should be done on a track - warm up then measure 3 or 4 consecutive miles. I can see why the track is sensible because only on a completely flat surface with wind effect cancelled out can you run at a steady pace near your aerobic maximum. I tried a test on my local lanes and even the very small gradients caused a big variation within the range as I compensated, so it would not be reliably repeatable. Now I've learnt that I'm going to try another base test by running two directions along the canal towpath which I think will be much better.

So that's it. I'll see how it goes from now to the end of the year, and if anything interesting comes out, I'll let you know.


Chris said...

Maffetone's writing is really helpful. At 46 I try to stay 124-134. But for me that is 10 min miles. Your pace is pretty impressive!

Robert Osfield said...

Five years ago I tried running at heart rate suggested the Maffetone equations and found it impossibly slow. I stuck with it and just found my fitness got worse.

What I have since found out that it the guideline heart rate was totally inappropriate for me, the equation gives a heart rate that is 20bpm too low.

My lactate threshold heart rate is up in the around 175, and my max HR is up around 190, these figures are both very high for someone my age (45) is likely why the Maffetone equation is so wrong for me. From what I've learnt other sources my "MAF" is probably in the around 155 to 160bpm.

For those thinking about trying Maffetone approach out I'd recommend doing a lactate threshold run to find out what the heart rate is and then subtract 20bpm. Your average HR during a 10k is probably not too far off - my last two 10k's I averaged 174bpm.

As for the using the MAF heart rate for all training for a 3 month period. This is probably not required or optimal, but not necessarily a bad base to work from. Running 90% of your runs at or below MAF, and 10% higher pace. Doing two to three faster sessions per fortnight is probably sufficient. So sprinkling an interval session or tempo or 5k/10k races is probably closer to ideal training.


One benefit of doing runs against a heart rate monitor over mixed terrain is appreciation of what constant effort level feels like. You highlight this in your post Andy, but there is a further benefit of developing this skill - when we race ultra marathons is important to even out the effort level so the very skill you develop in doing an MAF run is what you can apply when racing ultra's.

It allows you to finely tune just when you should walk up hills, how fast you run the levels and down hills. What I have found that as I've got fitter more of the hills I used to walk in ultras I can now safely jog up. If I hadn't the heart rate monitor there to tell me it's OK to run I would end up walking far more than I need to.

Andy Cole said...

Thanks for the feedback Robert, interesting stuff. I think I fit the "standard" HR profile pretty well, ie taking my age from 220 to give maximum HR gives 154; last time I measured it a couple of years ago it came out at 159 so that seems about right. The MAF speeds also feel fine for me at the moment as a way of building up running miles again without risking injury (I haven't really run consistent miles for nearly a year now), so I'll persist for the time being and see how it goes.

Anonymous said...

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