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Non-exact race distances? (Read 125 times)

kcam


    Based on my experience (unless you ran among tall buildings or a heavily forested area) 3.23miles for a '5K' was probably a long course.  I don't question a 5K's accuracy if my GPS reads about 3.11 +/- a couple percent.  Yours is well out of that.

     

    As well as selecting certified courses, to further improve chances of an 'accurate' course select a race put on by a PROVEN race management company.  if this is important to you you have to do your research before you sign up.  Luckily where I live there are several such companies/organizations around and lots of certified courses but the occasional short/long course still happens.  Life goes on.

    M.Burrows


      I do some race timing as a side gig but steer away from course layout and safety.  I don't need the liability issue if there is an injury.  I stress to race directors that the course needs to be well marked (before, during and after intersections) and the distance needs to be correct.  On a gps watch or even the mapping tool here on RunningAhead a 5K (for example) should map to 3.14 miles to be accurate.  I've wheel measured and bike measured some courses to confirm this.  That said ... race directors and volunteers who are not runners don't understand the importance of this advice.  They are caught up with t-shirt design and orders or how many bananas to supply at the finish line and skimp on the actual race details at times.  It's just the reality of small, local fundraiser events.  There is less excuse for the bigger half and full marathons to have a wrong distance.

        I do some race timing as a side gig but steer away from course layout and safety.  I don't need the liability issue if there is an injury.  I stress to race directors that the course needs to be well marked (before, during and after intersections) and the distance needs to be correct.  On a gps watch or even the mapping tool here on RunningAhead a 5K (for example) should map to 3.14 miles to be accurate.  I've wheel measured and bike measured some courses to confirm this.  That said ... race directors and volunteers who are not runners don't understand the importance of this advice.  They are caught up with t-shirt design and orders or how many bananas to supply at the finish line and skimp on the actual race details at times.  It's just the reality of small, local fundraiser events.  There is less excuse for the bigger half and full marathons to have a wrong distance.

         

        I certainly believe this. Even (or especially) at larger events - competitive racers who are seriously concerned about precise distance and finish times are a small percentage of the participants, and therefore small percentage of revenue dollars. Most people are there for a fun day out, support a cause, jog with friends, push strollers, wear a costume, etc. Race organizers are naturally going to focus their resources on what is more important to the majority of their customers - t-shirts, medals, post-race food spread, music, etc. Presumably these are the things that attract people & keep them coming back. Of course many of the organizers are runners and I believe genuinely want to get time/distance right too. But shit happens.

        Dave

        JMac11


        RIP Milkman

          Good points on the distance measuring and what a lot of RDs are really about. The effort to get the course correct is very difficult, even if it’s certified. Besides even missing cones or ones placed in the wrong spot, I’ve run a lot of smaller races where there are cars parked on the street, which remove any chance of you running the tangents.

           

          This whole issue of course certification is one reason that a) I only run USATF certified courses (or the equivalent) and 2) Only run races set up by established running clubs. The chances that your local charity 5K run is going to be accurate is not great. I ran a half last year that said it was certified but pretty much every single runner came in at 13.0 or under. Once you run real certified courses (I’m blessed with NYRR) you realize that your GPS should be behind schedule by mile 2, even on a course that seems pretty straight.

          5K: 16:37 (11/20)  |  10K: 34:49 (10/19)  |  HM: 1:14:57 (5/22)  |  FM: 2:36:31 (12/19) 

           

           


          All About that Pace 2024

            Hilarious.  A traffic signal in Italy.  I'm keeping that one.

             

            The Dementor

             

            It is not uncommon at all, a scan through my log here for my race "career" includes...

             

            Half marathon:  12.8mi, 13.4mi, 12.8mi

            5K: 3.0mi

            10K: 6.1mi, 6.05mi

             

            All were "certified" courses.  Most were cases of turn around cone misplaced...but your average local 5K fund-raiser course is going to be like a traffic signal in Italy...just a suggestion.

             





              I ran a half marathon where my GPS distance was 12.47 miles.  The course was right, my GPS was off.

               

              When my Garmin FR310xt was still working, I recorded a waypoint in front of my garage, then looked at the distance to that waypoint when turning it on.  Immediately after the GPS screen claimed lock in with error less than 50 feet, it was common to see 0.25 miles to my garage.  Once, it was more than a mile wrong.

               

              My FR235 does not have that capability, so I used my bicycle to measure and mark 1 and 2 miles from my driveway.  The GPS is usually locked in correctly at one mile, so I can add any error at that point to the end result.  If I bother.

                Alot of people take strava as gospel for a distance too. I have to bite my tongue when a sub 3 marathon strava result is claimed in their comments even though they were a couple of minutes over on the race course.

                55+ PBs 5k 18:36 June 3rd TT

                " If you don't use it you lose it,  but if you use it, it wears out.

                Somewhere in between is about right "      

                 

                Altair5


                Runs in the rain

                  I always find a difference between official race distance, my Garmin reading and Map-My-Run. I would think a certified course is an exact measure. I don't know how the Garmin calculates distance. If you run up and down steep hills the total distance is going to be greater than a flat, birdseye view (square of the distance run is equal to the sum of the squares of the distance as shown on a flat map and the change in height). The same problem with the mapping feature, and I find the lines when I map the course do not exactly follow the roads on the map, some parts get simplified with a straight line even if the road is a bit crooked, also, some curves are cut a bit. Thankfully the discrepancy is usually small. I use the map distance to record my training runs and go with official distances for my races.

                  Long distance runner, what you standin' there for?
                  Get up, get out, get out of the door!

                  Marky_Mark_17


                    I always find a difference between official race distance, my Garmin reading and Map-My-Run. I would think a certified course is an exact measure. I don't know how the Garmin calculates distance. 

                     

                    Garmin purely works off the GPS satellite readings on your watch.  These aren't necessarily perfect and can be impacted by the quality of the GPS lock-on.  Trees, tall buildings, etc. can all cause it to be off by small (or large) amounts.

                     

                    Similarly, official race distance - even for a certified race - relies on running the optimal route around the course as it's typically measured with a wheel.  Running anything less than a perfect line around corners - or weaving to overtake - will add small inefficiencies. Cumulatively these can add up to over 100m on a half marathon.

                     

                    Of the races I've run on certified or measured courses:

                    Half marathon: 21.2km, 21.2km, 21.11km, 21.27km, 21.10km (GPS measured short on this due to a short covered spiral walkway)

                    10km: 10.13km, 9.82km

                     

                    I did some analysis of this on the sub-1:30 thread at some point.  Almost every half marathon that wasn't a certified course measured exactly 21.1km on my Garmin or shorter (i.e. all these were likely to be short accounting for course inefficiencies).  Some were as short as 20.7km. I'm not sure whether this is just slightly lazy course management or a sneaky trick to make times appear faster.

                    3,000m: 9:07.7 (Nov-21) | 5,000m: 15:39 (Dec-19) | 10,000m: 32:34 (Mar-20)  

                    10km: 33:15 (Sep-19) | HM: 1:09:41 (May-21)* | FM: 2:41:41 (Oct-20)

                    * Net downhill course

                    Last race: Maraetai HM, 10 Mar, DNF

                    Up next: Waterfront HM, 7 Apr

                    "CONSISTENCY IS KING"

                    Altair5


                    Runs in the rain

                       

                      Garmin purely works off the GPS satellite readings on your watch.  These aren't necessarily perfect and can be impacted by the quality of the GPS lock-on.  Trees, tall buildings, etc. can all cause it to be off by small (or large) amounts.

                       

                       

                       

                      If the Garmin does not factor in the distance added by elevation changes then the millage would be off. For example, if you ran what looks like a mile on a flat map and increased your elevation half a mile, you actually ran about 5.02 miles. As for Garmin glitches, I've had three major one that showed me running out a mile or so and back at some ridiculous speed. These each happened with a distant  lightning flash, standing next to a car and going into a concrete building. The last event actually showed me continuing my run in the opposite direction that I really traveled!

                      Long distance runner, what you standin' there for?
                      Get up, get out, get out of the door!

                      JMac11


                      RIP Milkman

                        Alot of people take strava as gospel for a distance too. I have to bite my tongue when a sub 3 marathon strava result is claimed in their comments even though they were a couple of minutes over on the race course.

                         

                        You biting your tongue on Strava? I didn't think that was possible.

                        5K: 16:37 (11/20)  |  10K: 34:49 (10/19)  |  HM: 1:14:57 (5/22)  |  FM: 2:36:31 (12/19) 

                         

                         

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