I run a wide range of distances from 5k up to (soon) half marathon, and I wanted to find a way to compare the relative quality of those runs. For example, which is the better achievement, a 10k in 53 minutes or a 5.9k in 28 minutes.
I found and read this article (https://rat.run/articles/content/age-grading) about age-grading race results, and then this online age-grading calculator: http://www.howardgrubb.co.uk/athletics/wmaroad15.html.
The JavaScript in the source for the age-grading calculator contained the World Masters Athletics (WMA) age factors for road running distances from 5k-200k and for ages 5-100. Converting these from JavaScript arrays into an Excel spreadsheet was very easy as the array declarations contain comma separated values.
For each standard distance run, there is a world record time. The 10km road running world record (in 2015) for example was 1603 seconds which is 26 minutes and 42 seconds. The factors in the table above can be used to see how my (44 year old male) efforts compare to this world record. From the table, I get a 0.9342 age-factor, so my 53 minute (3180 seconds) 10k time can be reduced to an age-graded result of 0.9342*3180 = 2971 seconds (49 minutes 30 seconds) which sounds more impressive but is still a long way away from being a world class performance.
To calculate the age-grade score of my run to the world record, the world record time is divided by my age-graded result. In this example, that would be 1603/2971 = 53.95%.
To look at non-standard run distances – e.g. 10.83km, you have to interpolate between the standard race distances found above and below it – in this case, 10k and 12k. There is a 2km difference between those two distances, and my 10.83km is 0.83km longer than the 10k. We take the world record for 10k time and then we add (0.83/2) * (WR 12k – WR 10k) to estimate what the world record time for 10.83km would be.
1603 + (0.83/2 * (1942-1603)) = 1744 seconds.
This value can then be used to to calculate an age-grade score for my 10.83km runs, and to compare them against runs of different distances.
To avoid using VBA macros (which can make it impossible to ‘undo’ mistaken actions), I broke the calculation steps up using standard Excel functions (as shown above), and now I have incorporated WMA age-grade scores in my running record dashboard (as shown below).
Looking at my runs so far during 2021, the WMA age grade scores follow closely with the speed of the runs in the above sorted run speed table (primarily because of the limited range of distances to far run this year), but there are differences:
The 12.96km run at 10.642km/h is better than the 6.70km run at the higher speed of 10.701km/h.
The 10.59km run at 10.837km/h is better than the 8.51km run at the slightly faster pace of 10.841km/h.
Taking into account age and different distances run, it is possible to compare recent and historical training runs of all distances with others as shown above (my best runs of February 2021 are highlighted in yellow).