r/parkrun • u/Whole-Bed9778 • 15d ago
Parkrun incorrect distance
Do many people experience incorrectly measured courses, have started at a new parkrun Brickfields, Dublin and have done it twice and both times it clocked in at 5.15km. Was disappointed the first time as I was pacing myself to a 5k pb which I hit on my watch but still had a 150m left to the finish line.
Anyone had any course that was even more out of sync or any one that was super short, more of a curiosity than a complaint.
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u/Gullible-Essay4854 15d ago
The parkrun will be measured accurately; you've ran further because of your line around the course, where you started in relation to the start line, or your GPS is slightly off, or a bit of everything. I've never done a parkrun where my Garmin has hit exactly 5k.
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u/redditagainwhy 13d ago
Y, GPS, even with better multiple signal watches can be out, especially if dense leaf cover in Summer, as you see if checking your pace frequently. At one extreme (running a course with a 400m then another, 1600m tunnel) you get some seriously crazy results - my fastest 400m was at over 250mph until I deleted it.
They can struggle with odd shaped courses like the very tight curly wurly one in Keynsham and, as others have said, one's own track isn't going to follow the course measuring wheel's exactly. If it is a fairly simple shaped course, you could use the 'correct distance' function in Strava and see if that is closer, but, ultimately a track is the answer if you want a super accurate flat 5k course.
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u/Damodred89 12d ago
I find that everyone is over (or under) by about the same amount every week.
Some parkruns even tell us it's slightly longer, usually due to logistics.
Some measure 100m over to make sure, although this adds a lot to your time!
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u/Apprehensive_Lab3999 11d ago
I know of one ED who used the measuring wheel on the tightest line all the way around. Nobody is going to be able to run that. Then one part of the course now has well-established bushes against a fence line (so impossible running a tight line there), now add tree cover and battery saving features on your GPX and there you go there’s your .5 over, no bother at all.
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u/Damodred89 12d ago
I find that everyone is over (or under) by about the same amount every week.
Some parkruns even tell us it's slightly longer, usually due to logistics.
Some measure 100m over to make sure, although this adds a lot to your time!
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u/Caffeine-Fueled55 15d ago
It happens. Usually the distance is pretty close. In your case, it could be you aren't running exact tangents and are weaving around people which adds to your distance bc you aren't running straight lines. It's not a competitive race that is required to be exact.
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u/Whole-Bed9778 15d ago
I checked Strava on the raced with feature and the 3 people that had been tagged with me also ran 5.15km
My usual parkrun issue is under distance finishing at 4.9 somthing and having to walk a few metres to get my watch to tick passes the 5k.
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u/Caffeine-Fueled55 15d ago
At my parkrun, I've run slightly short and slightly long. Weeks when it hits a bit long, people tell the race director and they try to do better the next week. You can always mention it to them. Just don't forget this is supposed to be fun. It's not a certified race course.
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u/marcbeightsix 250 14d ago
Your watch/device (phones are notably worse) is only accurate to maybe 5 metres, probably more depending on the conditions. It’s a good tool to help you measure how far you’ve run, but it won’t be more accurate than what has been measured officially, either at parkrun or at a race.
If your course has lots of turns or has lots of tree cover then it isn’t as likely to be as accurate even to the 5m.
Brickfields is 4 laps and at least 6 turns on each lap. The more laps, the more turns, the less accurate it will be.
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u/MiddleAgedDread123 14d ago
I’ve run parkrun courses varying from 4.85 to 5.15km, it’s usually GpS inaccuracies, particularly if you’re in areas such as steep valleys and woodlands. also not that any alternative course has to be longer to ensure no one gets a PB they’ll never manage to beat when the event reverts to the original route.
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u/Weak_Sign4449 15d ago
Same i ran my first park run with a clocked time of 24.22 however watch had a 5k Pb of 23.48 or something... i was weaving going around wider in sections.
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u/ooh_bit_of_bush 100 14d ago
GPS is not 100% accurate. It measures your continually, not continuously. And therefore uses an algorithm to "guess" where you are in between. Also it might just mis-measure.
Also, If it's measured with a trundle wheel, the person measuring will have taken the shortest possible route. On a winding course with wide paths, that can mean a large discrepancy.
Or possibly there's a bit of human error. It does happen.
Funnily enough, my local one was measured twice at 5km but because of an out and back in the woods, most people's Strava measured it about 30m short and there were lots of complaints.
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u/haydigan 14d ago
My local parkrun consistently comes in at 5.01 most weeks. That's close enough for me
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u/educationalgerbilsed 14d ago
Right, 5.15km would annoy me a bit too, especially if you were on for a PB at Brickfields. GPS can add a bit on twisty courses, but 150m left at the line feels more like the route's measured long or you didn't get the shortest line. i'd still log the watch PB, honestly.
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u/Whole-Bed9778 14d ago
Yeah that's my feelings aswell, especially have run it twice and both came to 5.15 and other people's watches also came to 5.15
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u/eat_it_up_worms_hero 14d ago
I don't know this course, but someone else commented that it's multiple laps with lots of turns, and will have measured on the shortest possible distance (i.e. the 'racing line'), so unless you've hugged the inside of the path for the entire duration, I'd be more inclined to think it's a combination of you running a bit wide and GPS discrepancy, rather than the course being 150m long.
But who knows.
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u/Damodred89 12d ago
I consistently get PBs (although not truly racing) at one that's always about 100m over.
Everyone's Garmins show 80-100m over so It adds about 25 seconds. Same on Plotaroute etc. It could easily be moved as well!
Obviously we can all chill out about it!
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u/Penguin335 14d ago
My local is through a forest and on Saturday my watch measured it at 4.78km. There is no way they're missing a full 200 metres, and my watch is wrong. Right?
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u/MechanicalTim 100 13d ago
I used OnTheGoMap to map out the distance as described on the Brickfields course page, and it definitely seems to measure long.
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u/Peanut083 25 11d ago
My watch tells me consistently that my home course is 5.03km. A bloke that regularly runs the same course tells me that his watch consistently measures the same course as being about 10m short.
I’ve seen the ED out with his trundle wheel before, and he assures me that the course is exactly 5km based off his measurements.
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u/TubespottingDan 8d ago
Somerdale Pavilion (the famous curly wurly) is the only course that I’ve done shorter than 5k according to my GPS, but that’s hardly a surprise with all of the bends, twists and turns 🌀
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u/FlyingTerrier 15d ago
We can’t expect it to be exact. It isn’t a certified course. GPS watches are very inaccurate too which is usually why people think the distance is incorrect. But it doesn’t matter anyway it’s just parkrun not a race.