Aerobic Threshold Training

Although I've ran my fastet race of my life recently, I realize now that I have a poor aerobic fitness.  I have been reading The Big Book of Endurance Training and Racing by Philip Maffetone.  Was there something to this low heart rate training to increase aerobic capacity?  I decided to try it.  Last weekend, I ran a 5-mile race and averaged <6:30 per mile.  I can run an 18.5min 5km.  But what is my max aerobic pace?  I calculated 180bpm - 41 years old = 139bpm.  Fixing that heart rate I ran 5miles.  Boy was I surprised how slow that is for me!  But it is my baseline and I plan to try this for a few weeks before my next race.  My results: 

mile   pace 
1       11:16.5 
2       11:04.7 
3       11:08.8 
4       10:55.2 
5       10:47.9 

According to the book, if I was in good aerobic shape, I'd be clicking off <7min/miles for 5miles at 139bpm.  

Here's a great FAQ on MAF training. 50 FAQs about MAF training:

Here are some of my answers to frequently asked questions for low heart rate training, generally pertinent to Maffetone's approach. Disclaimer: read at your own risk. Author is not responsible for any health conditions, reduction in performance, injuries, death, or humiliation that results from reading or following this advice. For professional advice, see a physician and get a coach. 

1. What might indicate that I could really use some low heart rate training? 

You have poor aerobic fitness, which doesn’t necessarily mean that you aren’t a good or a fast runner. You can be running 2:45 marathons and have poor aerobic fitness (which means perhaps you're capable of 2:15 or faster marathons and hence you can probably run a 5k in about 14 minutes). Maybe you run a 20 minute 5k, but a 4 hour marathon. Here are some possible indicators:

a. There is no pace “relationship” between your shorter distance races and your longer distance ones. What does this mean? There’s a good explanation in Hadd’s article below, but there are some rules of thumb to the effect that, if you assume you are properly trained for the distances you are racing, your pace will decrease by the same amount, each time you double the distance of your race, usually somewhere between 12 and 16 seconds, depending probably on genetics. Therefore, on the lower end, one who runs 5 miles at an 8 min/mi pace would run 10 miles at 8:16/mile, and 20 miles at 8:32/mile. The relationship may degrade some, particularly as the distances get longer in between (say 5k to marathon, or even half to marathon), but you should still see a relationship. If the math is getting too messy for you, you can use a common pace calculator, such as that at McMillan Running and see whether your short distance times project out to long distances. If your marathon is more than 20 minutes slower than what your half predicts, then there’s a good chance you have an aerobic problem, assuming (1) you completed a full training program for the marathon and (2) the marathon was not in abnormally high heat and/or humidity or had other significant environmental factors.

 

b. You are incapable of running at low heart rates, for example, you find you have to walk at a heart rate of 180-your age.

c. You always burn out somewhere between mile 16 and 22 in a marathon, no matter how much carbohydrate you take in.

d. You have difficulty completing your long training runs and your pace slows down in the last several miles, just in order to finish them.

e. You are completely shot at the end of your long training runs, or even your short runs. (You probably will be after most forms of speed work, that’s expected, to a degree).

f. You are sore most of the time and possibly plagued by minor injuries frequently, or you get sick quite often.

g. Your race times are not improving – it seems as though you are working harder and harder in training and nothing’s getting better.h. You are very reliant on carbohydrates to get you through training runs. 

 2. What are some of the relevant websites? Mark Allen on Ironman Live Maffetone Hadd Mark Allen - duathlon.com Matt Russ Pfitzinger on basebuilding Pfitzinger on fat utilization 

3. What benefits might I reap from low HR training?  ....Total of 50 comments here