Marathon Pace - More Numbers

Last Sunday was a massive confidence boost. It's still seems a little strange that a race where I held back by a lot showed I should be able to reach my marathon goals:

Run sub 3:00:00 in the Melbourne Marathon 2009

Keeping in mind my PR over the distance is 3:09:10 back in 2003, it is a big ask to take about 10 minutes off.

To move beyond my initial excitement, and be more objective I need to geek things up and crunch the numbers.

I've used the following numbers to guide my training:
HRmax: 188
MAF HR: 153 (81%HRmax)
Aerobic Conditioning: 132-153 (70-81%)
Threshold Zone 154-169 (82-90%)

From the Princes Park 30km:
HRav 157 (83.5%) @ 4:13/km (translating to a marathon time of 2:58:07)

Excluding the first 5km where I overestimated my pace and ran relatively slowly at 4:23/km, the next 20km were fairly consistent. The averages as listed above appear to be a very good guide as to what I should be aiming at. It will be interesting to see how my marathon pace training runs reflect these numbers in a month's time.

Endurance Threshold

This is a concept I find interesting. So far I've only heard it described Gordo Byrn and Joe Friel ("Going Long") in reference to Ironman triathlon. Essentially it is the limit of your basic endurance. The point or distance at which things became significantly harder or beyond which you just slow down. Based on last Sunday, (running at near marathon pace) this distance appears to be about 26km. It was at this point there was a noticeable increase in difficulty in maintaining the required pace. Even though it was still very doable, it was also very easy just to slow down. Coupled with this increased effort, there was a jump in my heart rate from a range of 156-159bpm (which had been reached gradually) to a range of 162-165bpm. While it is quite possible for me to maintain this pace and effort level for a reasonable amount of time, I would predict that time frame currently falls short of the full 42.195km.

There are a few possible ways of addressing this issue.

  1. Extend my basic endurance so this point goes beyond 26km
  2. Decrease the relative intensity/effort required to maintain marathon pace
  3. Increase the ability sustain the higher effort level beyond the endurance threshold

I like the idea of working on all three points.

True Marathon Intensity

The common advice and usual aim of marathon pacing to maintain something very close to a steady and even pace throughout the whole event. Recommendations vary slightly between aiming for an exact even split, a negative split and a slight positive split for various reasons. Essentially the recommendations all aim for a variability of less than +/- 2% of the average pace. In reality very few people achieve this so-called ideal. For most, a marathon race involves a number of ups and downs in pace, feeling, intensity, emotion and not to mention the requirements of changes in terrain. Most marathon World Records have been achieved with near even splits. While the running speed may be relatively consistent, the effort level rarely is. There is the concept of increasing heart rate due to factors such as dehydration, decreases efficiency, shift in substrate metabolism, and other aspects of fatigue. Further there is often an associated increase in oxygen consumption/ventilation rate. Reduction in ventricular efficiency, possible mild pulmonary oedema and changes in cellular permeability are further factors occurring in a marathon.

It seems to be accepted average marathon pace is just below the a person's anaerobic threshold. Unfortunately defining the anaerobic threshold is an endless argument in itself. Further beyond separating marathon pacing between extremes of 5, 4, 3 or 2.5 hours, it is a very poor indicator of predicting an accurate finishing time. Elite athletes showed a significant amount of oxygen consumption and heart rate increase between 3 and 10km of running at marathon pace.


The numbers are a good guide, but a guide is all they can be. I'll use them to guide my, do some runs above, below and at race pace. See how I respond and take it from there for race day. Then hope I can get that bit extra out of myself on race day.


  1. Interesting numbers Jason.

    Improving on all three would seem like a good idea.

    My thoughts are the most reliable way to break 3 hours would be to extend the basic endurance. You could possibly combine this with #3 by doing, say, a 27k easy run followed by 10k at best effort.


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