This year’s Shamrock Runs (and several other multi-race events in the TRL Summer Series) will be scored as single races, with adjustments not only for the differing distances, but for the difficulties in the courses.
In the interests of transparency, here’s a quick peak under the hood of how I do it.
First, I need a difficulty adjustment for each course, since some are flat, and others aren’t. To do that, I am calculating a difficulty factor based on parameters I have long used in coaching. These show that every 50 feet of climbing slows you down by about 15 sec, while each 50 feet of descent gives you back up to 10 sec, if you are a good downhill runner. That’s a net 5 seconds loss for each 50 feet up and down. If you’re not good on hills it might be 50 percent higher, but I have to pick a parameter, and focusing on good hill runners seemed best.
In my experience, these are good estimates for people running about 6 minutes a mile, so I scaled to that pace, calculating that running up and down 50 feet in a mile slows you by 1.39 percent. (That’s way too precise, of course. Think 1.4 percent, give or take maybe .2 percent.)
The slowdown is linear in over a wide range: i.e., 100 feet has twice the effect of 50 feet. This means I can use the total amount of climbing as reported on course maps to calculate an average amount per mile, kilometer, etc., for the entire course. That produces a handy handy spreadsheet I can easily adapt for other races–with the caveat that it doesn’t apply to net upgrades or downgrades.
| Race distance (m) | Total climbing (m) | Average upgrade | Parameter | Difficulty factor |
| 15000 | 239 | 1.59% | 1.39 | 2.21% |
| 21000 | 261 | 1.24% | 1.39 | 1.73% |
| 5000m (2024) | 46 | 0.92% | 1.39 | 1.28% |
| 5000=m (2025) | 0 | 0 | 1.39 | 0 |
| 8000m | 0 | 0 | 1.39 | 0 |
How this was calculated
• Slowdown per mile per 1% upgrade: 15 sec
• Speed-up per mile per 1% downgrade: 10 sec
• Up-and-down average per 50 feet: 5 sec slowdown.
• Effect of pace, compared to 6:00 pace (“parameter” in the table): 1.39
Once race times are adjusted for difficulty, I can then put them into age-graded tables. For non-age-graded races, I simply use open-class times. That gives a quick-and-easy way to compare, say, 80 minutes on the half- to 21 minutes on the 5K.