Back in October I shared my idea to switch my marathon training metric focus from heart rate to pace. Since then I have found more support for this idea. Joe Friel himself makes an excellent case for this in the context of cycling, in his book, "The Power Meter Handbook." The problem is, nobody has a practical way to measure power while running, so heart rate is generally considered the next best metric. (Actually there is a company developing a waist mounted accelerometer that measures power while running. D.C. Rainmaker has tried a beta version.)
Ryan Riell has posted an interesting piece on the Training Peaks blog, "How to Train for an IRONMAN Marathon," and in it he makes a case for training by pace instead of heart rate. He does not throw out heart rate, rather he acknowledges the variability typical of heart rate and why that makes it a poor choice for monitoring performance. A better approach, he argues, is to establish pace zones that are analogous to heart rate zones and power zones. He points out that heart rate is an input metric, whereas power and pace are output metrics. Joe Friel compares training by heart rate with trying to manage the speed of a car by monitoring fuel consumption.
Riell suggests using recent marathon performance to establish three pace zones, then use that data to calculate three zones for Ironman pace. Clearly this approach is designed for top performing age groupers. He hints at this when he describes two example athletes, one who runs a marathon in 3:15 and another in 3:45. I for one would be thrilled to run a half marathon in that time.
It turns out that Riell's piece includes a hint about a method by Joe Friel for establishing pace zones. I searched around Training Peaks and found it. What a nice surprise. I like Friel's method because it relies on a 30 minute effort, something achievable by anybody bothering to fuss with this stuff. The same test I do regularly to set heart rate zones. If only Garmin had a display for these zones, like they do for heart rate and power. When I have some time I want to look back over my recent 30 minute time trials and see how my pace zones turn out.
I should point out that I am training for the Honu Half Ironman. Strictly speaking, my goal pace should be faster than the Ironman marathon pace. At my level, anything faster than walking is good. But it is nice to have goals.