Discussion
Does it have any really tight corners or sections under trees? I find that's where my Garmin usually gets it wrong. How about the start? I've been to a few with a narrow start where you gain a fair bit of distance just crossing the start line.
Looking at Strava it seems mine has measured between 4.92 and 5.09 for my usual course, so pretty much bang on 5km average which actually surprises me.
Looking at Strava it seems mine has measured between 4.92 and 5.09 for my usual course, so pretty much bang on 5km average which actually surprises me.
RizzoTheRat said:
Does it have any really tight corners or sections under trees? I find that's where my Garmin usually gets it wrong. How about the start? I've been to a few with a narrow start where you gain a fair bit of distance just crossing the start line.
Looking at Strava it seems mine has measured between 4.92 and 5.09 for my usual course, so pretty much bang on 5km average which actually surprises me.
That's an interesting variation; I guess it may be my small sample size that's showing this. That said, I've yet to see any variation at all in my Parkrun distances - they're all bang on 5.10km. Do you start at the line each time? I literally have my foot on the line at the start, click the watch as soon as the gun goes off, and then click it again as I cross the funnel timer. I'm guessing by their times that the people I've clicked through on Strava also start at the front. There are a few overhanging trees on ours, but no real tight corners.Looking at Strava it seems mine has measured between 4.92 and 5.09 for my usual course, so pretty much bang on 5km average which actually surprises me.
RobM77 said:
I want to know when to celebrate: when my watch says I've done it, or when Parkrun says I have 
The only times that will count and available for posterity are those on the Parkrun website ... 
My money is on the course having been measured accurately. As is evidenced on this thread GPS sports watches can show significant variations in how the distances are measured. Yours may have options to automatically compensate distance for elevation changes and the frequency at which it samples position ('smart' sensing or every second), all of which will impact the distance reported.
Just run a bit faster and it won't matter what your watch says.
RobM77 said:
That's an interesting variation; I guess it may be my small sample size that's showing this. That said, I've yet to see any variation at all in my Parkrun distances - they're all bang on 5.10km. Do you start at the line each time? I literally have my foot on the line at the start, click the watch as soon as the gun goes off, and then click it again as I cross the funnel timer. I'm guessing by their times that the people I've clicked through on Strava also start at the front. There are a few overhanging trees on ours, but no real tight corners.
Hell no, we have about 600 people and at 27ish minutes I'd be a rolling roadblock . We have a reasonably wide start though so I'm usually only 5-10 yards back, but I've done some where it's taken me 20 seconds to cross the start line I've recently replaced my Fr610 with a Fenix, not done enough runs with it yet to see if there's a difference between the two. The new one can also do Glonass and Galileo so I should have a look at how thier accuracy compares at some point.
Cybertronian said:
All kicking off at my local, Cannon Hill, having announced that running with dogs will be banned from mid-May onwards.
Some dog owners can see the bigger safety issue and have taken the decision with humility. Others have taken the decision personally and badly, forgetting that running with dogs at events is not universal.
Won't be long before buggies are banned, I reckon.
I think that's a real shame and missing out on the whole inclusive ethos (as I see it), I've done 2 different park runs in the last fortnight in one the first place runner was running with a dog, in the other it had a narrow start and after about a 1/4 of a mile I caught up with a woman power walking with 2 sticks flailing around, she was a massively inconsiderate rolling roadblock but what can you do? She's entitled to be there and it isn't a race.Some dog owners can see the bigger safety issue and have taken the decision with humility. Others have taken the decision personally and badly, forgetting that running with dogs at events is not universal.
Won't be long before buggies are banned, I reckon.
The problem with course length is that there are at least 3 inaccuracies in parkrun measurements.
1 Garmins are not accurate. Never, not ever, cannot be relied on to give the right distance - maybe they will if you go slowly in a straight line where there are no buildings or trees and good satellite coverage but in the real world they just aren't, partly because they don't record all the time, they are like a graph, points joined by straight lines so you can go 5 m, round a U turn and back and they think you've moved 1m to the left and partly because the route should be measured the shortest way round and generally it isn't possible to run that.
2 Most parkrun routes aren't measured by a qualified course measurer, they're done by the Ambassador or Event Director who do it to the best of their ability, understanding and patience, so they do vary. Off road courses are a particular b
d - I measured one 3 times with a wheel and got a different answer each time so had a guess and fitted it to the available space. Fortunately it's so hilly only a complete idiot would complain that it was short 
and it generally comes out at 5.0 on a Garmin despite the fact that I know it's short!
3 Different people set up the course each week and if it relies a lot on markers on a field rather than paths it might be different each week.
So overall there's no way of knowing what's right or wrong, they are mostly around 5k and we have to just go with it!
1 Garmins are not accurate. Never, not ever, cannot be relied on to give the right distance - maybe they will if you go slowly in a straight line where there are no buildings or trees and good satellite coverage but in the real world they just aren't, partly because they don't record all the time, they are like a graph, points joined by straight lines so you can go 5 m, round a U turn and back and they think you've moved 1m to the left and partly because the route should be measured the shortest way round and generally it isn't possible to run that.
2 Most parkrun routes aren't measured by a qualified course measurer, they're done by the Ambassador or Event Director who do it to the best of their ability, understanding and patience, so they do vary. Off road courses are a particular b
d - I measured one 3 times with a wheel and got a different answer each time so had a guess and fitted it to the available space. Fortunately it's so hilly only a complete idiot would complain that it was short and it generally comes out at 5.0 on a Garmin despite the fact that I know it's short!3 Different people set up the course each week and if it relies a lot on markers on a field rather than paths it might be different each week.
So overall there's no way of knowing what's right or wrong, they are mostly around 5k and we have to just go with it!
KTF said:
The new Apricot range is live today:
https://www.prodirectrunning.com/c/parkrun-apricot...
Ooof, £33 is fierce. Imagine I'll get one anyway...https://www.prodirectrunning.com/c/parkrun-apricot...
Edited by KTF on Thursday 25th April 10:52
john2443 said:
The problem with course length is that there are at least 3 inaccuracies in parkrun measurements.
1 Garmins are not accurate. Never, not ever, cannot be relied on to give the right distance - maybe they will if you go slowly in a straight line where there are no buildings or trees and good satellite coverage but in the real world they just aren't, partly because they don't record all the time, they are like a graph, points joined by straight lines so you can go 5 m, round a U turn and back and they think you've moved 1m to the left and partly because the route should be measured the shortest way round and generally it isn't possible to run that.
2 Most parkrun routes aren't measured by a qualified course measurer, they're done by the Ambassador or Event Director who do it to the best of their ability, understanding and patience, so they do vary. Off road courses are a particular bd - I measured one 3 times with a wheel and got a different answer each time so had a guess and fitted it to the available space. Fortunately it's so hilly only a complete idiot would complain that it was short and it generally comes out at 5.0 on a Garmin despite the fact that I know it's short!
3 Different people set up the course each week and if it relies a lot on markers on a field rather than paths it might be different each week.
So overall there's no way of knowing what's right or wrong, they are mostly around 5k and we have to just go with it!
That’s interesting. I recently did a 19:58, my second ever sub 20 and fastest run in about 4 years. Unfortunately my garmin said I’d only ran 4.8km. So maybe I did do a legit sub 20 5k after all 1 Garmins are not accurate. Never, not ever, cannot be relied on to give the right distance - maybe they will if you go slowly in a straight line where there are no buildings or trees and good satellite coverage but in the real world they just aren't, partly because they don't record all the time, they are like a graph, points joined by straight lines so you can go 5 m, round a U turn and back and they think you've moved 1m to the left and partly because the route should be measured the shortest way round and generally it isn't possible to run that.
2 Most parkrun routes aren't measured by a qualified course measurer, they're done by the Ambassador or Event Director who do it to the best of their ability, understanding and patience, so they do vary. Off road courses are a particular b
d - I measured one 3 times with a wheel and got a different answer each time so had a guess and fitted it to the available space. Fortunately it's so hilly only a complete idiot would complain that it was short and it generally comes out at 5.0 on a Garmin despite the fact that I know it's short!3 Different people set up the course each week and if it relies a lot on markers on a field rather than paths it might be different each week.
So overall there's no way of knowing what's right or wrong, they are mostly around 5k and we have to just go with it!
john2443 said:
The problem with course length is that there are at least 3 inaccuracies in parkrun measurements.
1 Garmins are not accurate. Never, not ever, cannot be relied on to give the right distance - maybe they will if you go slowly in a straight line where there are no buildings or trees and good satellite coverage but in the real world they just aren't, partly because they don't record all the time, they are like a graph, points joined by straight lines so you can go 5 m, round a U turn and back and they think you've moved 1m to the left and partly because the route should be measured the shortest way round and generally it isn't possible to run that.
2 Most parkrun routes aren't measured by a qualified course measurer, they're done by the Ambassador or Event Director who do it to the best of their ability, understanding and patience, so they do vary. Off road courses are a particular bd - I measured one 3 times with a wheel and got a different answer each time so had a guess and fitted it to the available space. Fortunately it's so hilly only a complete idiot would complain that it was short and it generally comes out at 5.0 on a Garmin despite the fact that I know it's short!
3 Different people set up the course each week and if it relies a lot on markers on a field rather than paths it might be different each week.
So overall there's no way of knowing what's right or wrong, they are mostly around 5k and we have to just go with it!
There's an additional one I've found that could entirely be down to convenience of having the start and finish in the same spot. Riverfront parkrun in Newport, Wales always measures long for me, no matter the GPS device I've used (Garmin Fenix 3, Garmin 935, Apple Watch GPS).1 Garmins are not accurate. Never, not ever, cannot be relied on to give the right distance - maybe they will if you go slowly in a straight line where there are no buildings or trees and good satellite coverage but in the real world they just aren't, partly because they don't record all the time, they are like a graph, points joined by straight lines so you can go 5 m, round a U turn and back and they think you've moved 1m to the left and partly because the route should be measured the shortest way round and generally it isn't possible to run that.
2 Most parkrun routes aren't measured by a qualified course measurer, they're done by the Ambassador or Event Director who do it to the best of their ability, understanding and patience, so they do vary. Off road courses are a particular b
d - I measured one 3 times with a wheel and got a different answer each time so had a guess and fitted it to the available space. Fortunately it's so hilly only a complete idiot would complain that it was short and it generally comes out at 5.0 on a Garmin despite the fact that I know it's short!3 Different people set up the course each week and if it relies a lot on markers on a field rather than paths it might be different each week.
So overall there's no way of knowing what's right or wrong, they are mostly around 5k and we have to just go with it!
Though, I accept this one is a rarity as most events have separate starts and finishes, so could easily just move either one closer/further as required.
I think if multiple GPS watches are showing distances with little variation that are different between one parkrun and the other (e.g. most say 5.1km, few less than 5.08km or more than 5.12km), then that's more reliable than the official measurement, which as I understand it is done with a wheel. If that wheel is just a tiny bit out then it'll have a big bearing on the final distance; for this reason wheels aren't really intended to measure long distances (i.e. over 400-500m). With regard to using a wheel, it's also worth noting that my local parkrun is on rough ground, so the wheel has to jump over stones and ruts constantly...
RobM77 said:
...If that wheel is just a tiny bit out...
If you do it properly you calibrate the wheel / bike by measuring a distance that's been accurately measured using a steel tape and then the wheel is as accurate as it can possibly be (leaving bumpy bits out of the equation!) but I suspect that most parkrun course measurers aren't so pedantic - I prefer to have things right and have an engineering background where we worked to thousandths of an inch so understand calibration and on my tarmac route calibrated the wheel and measured very carefully but as I said above had to admit defeat on the off road route!But, at the end of the day, it's parkrun and if the course isn't spot on then that's just how it is, I'm more upset these days if the cafe isn't decent
john2443 said:
RobM77 said:
...If that wheel is just a tiny bit out...
If you do it properly you calibrate the wheel / bike by measuring a distance that's been accurately measured using a steel tape and then the wheel is as accurate as it can possibly be (leaving bumpy bits out of the equation!) but I suspect that most parkrun course measurers aren't so pedantic - I prefer to have things right and have an engineering background where we worked to thousandths of an inch so understand calibration and on my tarmac route calibrated the wheel and measured very carefully but as I said above had to admit defeat on the off road route!But, at the end of the day, it's parkrun and if the course isn't spot on then that's just how it is, I'm more upset these days if the cafe isn't decent
I suspect most people just borrow a wheel and walk round. It's not a race at the end of the day, so the distance isn't critical.
Weather was pretty grim up here in Glasgow with it chucking it down with rain. Almost didn’t bother as motivation to run is pretty low just now due some niggling injuries that just won’t seem to go away. Managed to drag myself along and wasn’t even bothered about looking at my watch. Got to the finish line and was only 11 seconds off my pb for that event!
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