parkrun Adjusted Course Times – Difficulty Ratings

All 5k parkruns are not created equal. Some are obviously more difficult than others. ONE of the reasons some are more difficult is because of the time lost in the ASCENT and the inability to recover it all in the DESCENT.

In part, I recently covered “hardness” due to ascent in this following post “parkrun : Hardest & Easiest Courses in UK“, let’s look at parkrun difficulties in a little more detail.

parkrun : Hardest & Easiest Courses in UK | course difficulty

The tables further below attempt to quantify the time loss for you for each UK parkrun. This could be the first step you might want to take to compare your parkrun results from one event to another.

Sources: ascent from jegmar.com, much other stuff from @bondcrash

SURFACE CONDITION

Before we move on to ASCENT/DESCENT, just a quick thought on SURFACE CONDITION.

Putting altitude, wind, temperature, humidity and similar factors to one side you could also consider this rule of thumb for time lost due to surface condition.

• 0% Tarmac (essentially same as ‘track’)
• 1% lost, Good trail
• 2%  lost, Grass/Bad trail
• 3%  lost, Muddy XC terrain
• 4% lost, Sand & Snow

So on Bushy parkrun: let’s say it’s 50% good trail and 50% bad trail – with some fudged maths, that means you would lose 1.5%. That’s somewhere in the region of 20 seconds for someone doing a 20 minute time. ie maybe on the track you would be 20 seconds faster. BUT that track is also perfectly flat which should help even more.

Let’s talk about flatness now:

ASCENT/DESCENT

You lose about 1 second for every 1m of ascent at a pace of 5:00/km over 5km ie your fudged pace becomes  5:01/km and you lose 5 seconds in total.

parkruns tend to finish in the same place as they start ie I assume ASCENT=DESCENT. BUT you will recover no more than 60% of the time lost on the ascent. Let’s say 50%..it helps the fugded maths even more 😉

So the same person loses 5 seconds and gains back 2.5 seconds, losing 2.5 seconds over the entire 5k.

In the example below, Richmond Park parkrun has a handy ascent and descent of 50m. 50 seconds are lost and 25 seconds recovered giving a net loss of 25 seconds for the runner who runs track at 25:00/5k ie 5:00/km. The loss is proportionately less for those who run faster and more for those who run slower. Thus the 20-minute parkrunner loses 10 seconds.

But wait. Those of you who run Richmond at around that 20:00 time know the ‘common wisdom‘ is that about 30 seconds lost: So you also need to add in the good trail/bad trail/grass factor (above) and, for a 20 minute runner, that will be about 15-20 seconds.

And you need to adjust the recovery rate at which descent allows time to be recovered. Richmond Park is sufficiently steep to cause most runners to be unable to maintain their normal gait. The maths then come back to ‘about 30 seconds’. And before you ask, the model was derived initially at the much hillier Hampstead Heath parkrun 😉

What you will perhaps see is that the surface condition is likely to make more of a hit on your parkrun time than the hills in most cases.

Please take this as a ‘Straw Man’ I think it’s at least broadly indicative.

5K parkrun TIME LOST DUE TO ASCENT / DESCENT

Be careful when paging down – there are two tables below – the first one with a 50% recovery rate (conservative) and the second one with a 65% rate (probably the highest/most aggressive that can be recovered)

Using a 60% Recovery Rate ie from a GOOD runner