How accurately are Parkruns measured?

I've done our local Parkrun three times now. I use Endomondo on my phone to time/measure it (and it adds the calories I've burned into My Fitness Pal, so I get to eat more!), but it consistently comes up as over 5k. Almost 5.5 in fact.

There re are quite a few trees, and looking at the map of my run it does have me running off the path at times, so I suppose it could be wrong, but I assume it's correct when I run elsewhere.

So, am I running more than 5k, or does it mean that when I'm running elsewhere and I think I've done 5k, I haven't?

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Comments

  • literatinliteratin ✭✭✭

    Parkruns don't have to be 100% accurately measured, but if the map on endomondo shows you running off the path you know you ran on in real life, then it can't be an accurate record of exactly where and how far you ran.

  • Well, yes, this was my thought, but there again it's not showing me running wildly off it, more just parallel to it. Not enough to it add on 0.5k - or I wouldn't have thought so.  

  • literatinliteratin ✭✭✭

    It doesn't really matter that much, as it'll be close enough and if you want an 'official' personal best over a measured distance you can do a race on a certified course. If you're trying to lose weight, though, probably don't eat all the calories added to myfitnesspal, as the estimates tend to be on the generous side.

  • Some are bang on 5k, some are short in my experience. One of my local runs (I am lucky to have 5 park runs within 10 miles of me) is only 4.8km but it doesn't really matter. I haven't run any yet that were longer than 5k.

  • PompeyMattPompeyMatt ✭✭✭

    We had a problem sometime in Autumn last year when we all ran 4.5k at Southsea, it wasn't a big deal as we all know it's a free event run by volunteers and when times were uploaded they were suitably adjusted!

  • MillsyMillsy ✭✭✭
    A parkrun won't be as accurately measured as a certified race but will probably be more accurate than your GPS. You also have to take into account that the route your GPS records will not be exactly the same as the one the organisers measured.



    Is this extra 500m gong to make or break the diet plan??
  • No, it won't break the diet plan, and I don't eat all the calories back (but I generally eat some of them) - it just gives me a bit of leeway. Overall it doesn't really matter, I just want to know how far I've run and how fast. In the great scheme of things, it doesn't matter a button, I'd just like to know. Because I'm an obsessive control freak (until I get bored)...And I don't know whether I'm overestimating how far I'm running on other days, underestimating on Parkrun days, or possibly neither as the non-Parkrun routes I run have much less tree cover. 

  • I know a local one near me was short when it started but I went back and they'd moved the start line back about 100m - so there goes my PB.



    As the report says - they don't need to be super accurate. Just consistent.



    Who is to say you aren't running over distance anyway ? Loads of people at my parkrun are oblivious to running the shortest route.
  • MillsyMillsy ✭✭✭
    Some "B" / alternative courses are also measured slightly long to ensure that people don't get PBs that are out of reach when returning to the regular course.
  • Mobile phones and the tracking apps are not known for being the most accurate.  I have tracked a walk and compared it with someone else using the same phone on the same walk and come up with different distances.  What you can assume though is that if you consistently use the same device the same margin of error is applied to all of your activities therefore in my opinion you do not need to worry about it.

    Parkrun may not be as accurately measured as certified races but it is free and available to everyone and is doing a great job.

  • It's the margin of error on the device that I'm thinking of though. I'm trying to run 3 times a week, one of which is Parkrun. The other 2 runs I run 5k as measured by my phone and I believe it but then do I compare that time with what my phone measures as 5k of the Parkrun or do I compare it to the whole Parkrun. I know, it doesn't really matter...

  • Thanks for that link 2-wheels - it makes me realise I'm not obsessive at all!

  • literatinliteratin ✭✭✭

    I think the best way to improve would be to keep the parkrun as your time trial, but don't compare your other run times to it - instead, try to gradually build up the distance on one of your runs and go a bit slower, rather than trying to complete every 5k run as fast as you can manage. Then you can stop worrying about the accuracy of your phone, because you can just compare your parkrun performances and that course is always the same.

  • Well the thing is, the paths are quite wide at some park runs. If there are a lot of bends you can take the racing line (making a turn as straight a line as possible)

    By running in very efficient straight lines and not zig-zagging out between people,I have cut the recorded length of my local park run from 5.1k to 4.9k

  • Chris2304Chris2304 ✭✭✭

    Based on the (great) link that 2-Wheels posted it look likes Parkruns tend to be either bang in or a few (c.30 metres?) short. All-in-all that sounds pretty good to me, and is probably more accurate than mobile phone measurement, and broadly in-line with a Garmin

  • VDOT52VDOT52 ✭✭✭
    My ex-local parkruns are bang on. They are measured accurately by the same people who measure all official road races. I guess some parkrun setups are a bit more relaxed but those that are set up by club runners tend to be officially measured to 5.05km
  • Is a garmin more accurate than a phone then? Sorry if that's a stupid newbie question, but they're all using the same satellites surely?  I am tempted to get one, but thinking of leaving it till Christmas pressie time (mainly so I can get the hubby one, whereas if I get one now, he'll get himself one now!). 

    Our parkrun is 4 loops, 2 big and 2 small, but all clockwise, so the "keep to the left" mantra does mean slower runners (like myself!) will run farther than the faster runners. I don't expect there's 300m in it though, which is what mine and hubby's phones fairly consistent measure the course as (5.3km). 

  • You'd be surprised how much extra you can run by not following the racing line.

  • Chris2304Chris2304 ✭✭✭

    There are a ton of smart people on here, so I'm willing to be corrected on this, but as I understand it: Phone accuracy is getting much better. Modern iPhones are accurate to c.8-10m I believe, while a GPS watch is closer to c.5m. That difference can compound over time, obviously, but it's still bloody impressive!

  • NessieNessie ✭✭✭

    I have been for runs using the fitbit app and the runkeeper app *on the same phone* and the distances come up different.

  • Shona - if its clockwise and you're keeping to the left - then you're always running further.



    Shouldn't you be staying to the right and then the faster runners just go round you ?



    I'd rather have runners consistently in one place than veering over the road if I'm overtaking.
  • No, rules are stay to the left, overtake on the right. So the faster runners are running on the inside. No one veering over the road.

     

     

     

     

  • Running race courses worldwide are officially measured with a five digit mechanical counter (a Jones counter) attached to the course measurers bicycle wheel, with the counter calibrated before each course measure by cycling over an accurately measured predetermined one kilometer calibration section of road four times and the smallest resultant reading (just an ambiguous five digit figure on the Jones counter) then used to measure the pre-planned course (e.g. 10 x the smallest reading = 10K and so on). What is not universally known, is that all official course measurements are one one thousandth longer than the stated race distance, i.e. a 10K is 10 metres longer than 10 kilometers and a marathon is some 42+ meteres longer than is regularly believed to be the case and therefore, we should all reduce our PB's accordingly, to determine a true time for each specific true race distance. The officially alleged reason for the added distance is to compensate for anyone cheating by cutting a corner etc, which of course is an absolute nonsense, as in doing so, they are still cheating their fellow competitors and an actual race course distance then becomes totally irrelevant. If the 10K world record holder had cheated, what relevance had the adjusted 10,010 metre course distance achieved?
  • DT19DT19 ✭✭✭
  • DT19DT19 ✭✭✭
    edited July 20
    It's nothing to do with making sure cheaters dont run short. Youve identified the shortfall in that argument yourself in that they are still running shorter than everyone else as the course is long for everyone.

    It's simply a recommended safety buffer/margin for error to ensure course is accurate. Ultimately no one cares that much about cheaters unless they are winning prizes or getting gfa qualification. 
  • DT19 said:
    It's simply a recommended safety buffer/margin for error to ensure course is accurate.  
    It doesn't make the course any more accurate, it just makes sure it isn't short.  If the course measurement method is accurate to within 0.1%, then using a measured distance of 100.01% of the stated race distance ensures that the actual distance is at least the stated one.  Of course, the measurement error could be the other way and you actually have to run an extra 20m in your 10k

    As for reducing PBs accordingly, that has to be a troll, surely?  "The officially alleged reason" - what does that even mean?
  • DT19DT19 ✭✭✭
    My mara pb was set in London where my gps clocked 26.40. I know that has the Canary Wharf factor, but im sufficiently satisfied i ran a bit more than distance and have no need to reduce that pb. 
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