Relating to the Hadd Write-Up

I first linked to the Hadd write-up over two years back. I haven't been serious about starting a new endurance training cycle since then (after that post I had IMAZ, Florida 70.3, and IMMoo ahead in my 2007 season).

The Hadd write-up uses percentage of VO2 Max (well, "VO2max") extensively. For now, I'm using this conversion to go from percentage of VO2 Max to percentage of Maximum Heart Rate:
% MHR = 0.64 * % VO2 Max + 37

I'm using 200 as my maximum heart rate, although it must be a bit higher.

So, from Hadd's references, I have:
o type I muscle fibers being trained from as low as 50% VO2 max pace, or heart rate 138
o type I muscle fibers being optimally trained at 70% VO2 max pace, or HR 164
o type IIa muscle fibers being maximally trained at 85% VO2 max pace, or HR 182

Based on HR max of 200 (OK, properly based on a lactate threshold of 181, but that's the line of the chart that has HR topping out at 201), Friel (in The Triathlete's Training Bible (Second Edition)) has as heart rate zones:
o zone 1: 121 to 154
o zone 2: 155 to 164
o zone 3: 165 to 173
o zone 4: 174 to 180
o zone 5a: 181 to 184
o zone 5b: 185 to 192
o zone 5c: 193 to 201
A few other of my markers mesh well with those zones, so I think they're pretty close. It appears that Friel and Hadd were reading some of the same research (top zone 2 corresponds with 70% VO2 Max, zone 5a corresponds with 85% VO2 Max).

For my 2007 season, I did 12 weeks of base in zone 1 and was slammed when I moved on to zone 2. I had two words for the end of low heart rate training, and they weren't "happy birthday".

Maffetone would have my heart rate go no higher than 140 during base (and that's generously giving the maximum adjustment of +5 to the simple 180 - age). That corresponds to 50.6% of VO2 Max. Data from other studies suggest, and personal experience confirms, that's not going to do much for me. I am stuck believing that the great Mark Allen just happened to have a heart rate that fit well with the adjusted average of Dr. Maffetone's research subjects. Amongst many other qualities I mean.

I suspect that I have a relatively high proportion of type IIa muscle fibers (goes with the middle distance build) and so I would willingly train to be sure that I get a lot out of them, even at the cost of some compromising of training of type I muscle fibers. (I entertain minor thoughts of a Wingate Test to estimate proportions of muscle fibers).

All of this is not to say that Hadd has it close enough to right for most people, or that my estimates of heart rate zones and % VO2 max correspondences are particularly accurate. It seems to me that one very nice thing about the Hadd style of base is that it emphasizes benchmarking and progression. If one starts with heart rates that are too low, one will eventually progress to more appropriate heart rates.