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5K distance variation (Read 1825 times)


I've got a fever...

    In all seriousness, this was fascinating to me. I appreciate the lenghty explanation of both Ennay and gObLuE (I read it twice) and you've flipped me. Well done.
    Lank, you're so damn spineless. What a flip-flopper. Sticking with a position, even in the face of insurmountable evidence to the contrary, is courageous, admirable and is always far superior to someone who changes their mind.

    On your deathbed, you won't wish that you'd spent more time at the office.  But you will wish that you'd spent more time running.  Because if you had, you wouldn't be on your deathbed.


    A Saucy Wench

      Lank, you're so damn spineless. What a flip-flopper. Sticking with a position, even in the face of insurmountable evidence to the contrary, is courageous, admirable and is always far superior to someone who changes their mind.
      Wow, I have all kinds of responses to this...but most of them drift into the forbidden land of politics. Roll eyes

      I have become Death, the destroyer of electronic gadgets

       

      "When I got too tired to run anymore I just pretended I wasnt tired and kept running anyway" - dd, age 7


      I've got a fever...

        Lank, you must be like Stephen Colbert, who said, " I'm not a fan of facts. You see, the facts can change, but my opinion will never change, no matter what the facts are."

        On your deathbed, you won't wish that you'd spent more time at the office.  But you will wish that you'd spent more time running.  Because if you had, you wouldn't be on your deathbed.


        I've got a fever...

          Wow, I have all kinds of responses to this...but most of them drift into the forbidden land of politics. Roll eyes
          Maybe you should say it here. Or maybe not, depending on how you roll...

          On your deathbed, you won't wish that you'd spent more time at the office.  But you will wish that you'd spent more time running.  Because if you had, you wouldn't be on your deathbed.


          A Saucy Wench

            Maybe you should say it here. Or maybe not, depending on how you roll...
            Big grin

            I have become Death, the destroyer of electronic gadgets

             

            "When I got too tired to run anymore I just pretended I wasnt tired and kept running anyway" - dd, age 7

              As a fellow engineer, I read this earlier and thought, "hmm, someone doesn't quite get what they're saying about measurement and uncertainty. Maybe I should attempt to explain... nah... that'd take too long..." In the meantime all the other engineers apparently found the thread... Nice job Jeff. Smile
              Brandon
                Lank, you're so damn spineless. What a flip-flopper. Sticking with a position, even in the face of insurmountable evidence to the contrary, is courageous, admirable and is always far superior to someone who changes their mind.
                That's funny. Wait. No it isn't. Wait. Is it? I need someone to make up my mind because I can't decide.
                "Good-looking people have no spine. Their art never lasts. They get the girls, but we're smarter." - Lester Bangs


                A Saucy Wench

                  That's funny. Wait. No it isn't. Wait. Is it? I need someone to make up my mind because I can't decide.
                  It's best just to pick someone to emulate. Then if THEY say it is funny it is funny. You reduce the appearance of flip-flopping that way.

                  I have become Death, the destroyer of electronic gadgets

                   

                  "When I got too tired to run anymore I just pretended I wasnt tired and kept running anyway" - dd, age 7


                  I've got a fever...

                    To answer the OP's question, if a 5k course is certified, you have reasonable expectation of 5000 + 9/-0 meters, based on Ennay's numbers. If it's not certified, than it I'd day that the ±2% number that's been floated out there seems reasonable. But on an uncertified course, it depends a lot on who's setting the course up. A small race with the course laid out via a car odometer -- not so good. But a race with participation from a running store, running club, or some organization will most likely be fairly accurate.

                    On your deathbed, you won't wish that you'd spent more time at the office.  But you will wish that you'd spent more time running.  Because if you had, you wouldn't be on your deathbed.

                      Certified courses are very accurate but are measured by using all of the road tangents. So it measures the shortest possible course. When you run the race you probably will not take the tangents perfectly & you also will take a few extra steps going around people so if you run the 5k in less than 3.15 miles you did a good job. I think the only way to have the measurement be absolute would be on a straight route measured with a laser. Even the most accurate lasers are + - 6 inches per mile.

                      Courage ! Do one brave thing today...then run like hell.

                        The certification process is about the best we have and it's usually darn close. Last month I had a talk with a long-time USATF course certifier, and let me tell you--these guys are very anal about the accurancy of these courses, to put it mildly. It amazes me that so many many people will question the accuracy of a certified course because "my Garmin said...". A Garmin measurement isn't nearly as reliable as a certified course. If you want be sure that you actually ran as fast (or slow) as your watch said, race on a track or a certified course. But since it's not always possible to find certified courses and there are some pretty nice races that aren't certified, here is a method for the obsessive, "type A" nuts like me: Find the results of the previous running of the uncertified race you are interested in. Next, take a sample from the first 20 finishers and see what times they ran on other known certified courses. You can use a local results site, or one of the big ones such as athlinks.com. Compare those results with the uncertified ones and see if they line up closesly. If they do then it's probably safe to assume that the uncertified route is accurate.
                        Age 60 plus best times: 5k 19:00, 10k 38:35, 10m 1:05:30, HM 1:24:09, 30k 2:04:33


                        A Dance with Monkeys

                          Also, as far as a 2% error for uncertified courses, this is bullocks. Basic statistics, folks. Here is the deal: All courses are either the correct distance or they are not. Courses that are not the correct distance have an error. There is no reason to believe that a course with an error has a higher degree of error just because it was or was not certified. A statement that is more likely correct is this: There is a 1% chance that a certified course is the incorrect distance while there is a 5% chance that an uncertified course is the incorrect distance. (these are, of course, funny numbers to provide an example) Also, please remember that there are several steps to getting the correct distance - - measurement, in which the course is measured by a standard method* - layout, in which the race director and team sets up the course correctly along the measured course - race, in which the runners actually follow the measured route along the measurement line. *this is where certification comes in


                          Consistently Slow

                            #1 and #2 very good. #3 a little ifffy.

                            Run until the trail runs out.

                            2014***1500 miles 09/28/14

                            50miler 13:26:18

                            Race Less Train More

                             

                            Ana Trason  "Living Her Life"

                            "The Marble in The Groove"

                             

                            unsolicited chatter

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                            I've got a fever...

                              GPS error
                              This is one of the best GPS accuracy references I've seen yet. Excellent information.

                              On your deathbed, you won't wish that you'd spent more time at the office.  But you will wish that you'd spent more time running.  Because if you had, you wouldn't be on your deathbed.

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