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Trying to ONLY run 26.2 miles in a marathon (Read 2200 times)


A Saucy Wench

    Yeah when I race - any distance - auto lap is off and I manually hit the lap at the split markers.

    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

      For racing I use the Garmin, Auto Lap OFF - manually hit the lap button; always focus on running the tangents when it's safe to do so and I won't cut people off. But for training , Auto Lap ON, and I never run the tangents. As a matter of fact I try to always take the longest line around curves and such. I guess I foolishly believe that during a race when I run the tangents I get a mental edge versus what I did during training!


      Bugs

        I agree that running a marathon with a garmin may not make sense, and it some ways worked against me. For the first time I had the avg pace showing, and that really threw me off even though I knew that the garmin splits were not lining up with the mile markers. It wasn't all bad because it made me feel better everytime it auto lapped, and another sense of "making it" at each mile marker. This was my first race without a pacer, with no pacer I agree turn autolap off for sure. I don't like my garmin as much as I use to, too hooked on the numbers, tired of waiting for it to sync up, would rather run by feel etc... Man for the love of God I just want to run...but I do like to keep my log close to accurate and look back at my splits post race. So what would be a good watch to use when not using the garmin (for a marathon especially)?

        Bugs

        JimR


          Garmins sound like a great idea in training, but for the very same reasons they show race distances longer than the marked distance they will reflect an innacurate 'real' pace in training. If you ran side-by-side with someone on a measured twisty-turny course, you using the garmin and the other person using their watch and the course markings, you will record a faster pace than the other person even though you ran together. Because of that, your expectations can be off when it comes to an actual race.
            I just use a $50 timex ironman, same watch I use for running 95% of the time and the same watch I wear around most of the time. I don't even record my mile splits in most races. At Bay State I recorded every 5th mile split...

            Runners run.

              If I were a race director, this would drive me batty. GPS is NOT accurate enough to measure courses!!
              Amen. Yet despite tons of evidence and a zillion posts about this many continue to believe that Garmin is to measuring distance what the atomic clock is to keeping time...."but my Garmin said..."
              Age 60 plus best times: 5k 19:00, 10k 38:35, 10m 1:05:30, HM 1:24:09, 30k 2:04:33


              an amazing likeness

                Folks tend to far overstate the issue as one of accuracy of the GPS receivers (Garmin or Polar or whomevers). The major driver of distance differences is that courses are measured along a different line that the one we end up running due to tangents, due to not running right at the curve on the inside of each turn and corner, etc, etc. In my (limited) racing experience, I've seen people run 40' from the inside of a corner on the complete opposite road shoulder. Recognizing that my results are just a sample of one, here are some of my Garmin vs race distances, I'd call it pretty darn accurate: Office race distance / Garmin measured during the race 26.2 | 26.37 13.1 | 13.28 13.1 | 13.25 (same course as 13.28 above, different year) 10m | 10.04 10K | 6.27 10K | 6.25 10K | 6.23 5m | 5.04 5m | 5.02 (same course as 5.04 above, different year)

                Choosing my words carefully has never been my strength I've been known to be vague and often pointless


                A Saucy Wench

                  So what would be a good watch to use when not using the garmin (for a marathon especially)?
                  I guess I dont see why if you already have a garmin a reason to shell out $ for another watch. Just change your screens so it ACTS like a regular watch. If you have the X05 series you can take it down to just plain old time if you want. Or even something that seems meaningless when you are running to get you out of the numbers addiction. But then the data is there later if you want it.

                  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


                  Prince of Fatness

                    Ennay has a point, but I don't even want to be tempted. Plus, I don't want to even know how long the course measured with the GPS after the fact. It eliminates all of the what if thoughts. Here is the watch I bought at Target. It was $35. Timex watch at target

                    Semi-retired.

                      Folks tend to far overstate the issue as one of accuracy of the GPS receivers (Garmin or Polar or whomevers). The major driver of distance differences is that courses are measured along a different line that the one we end up running due to tangents, due to not running right at the curve on the inside of each turn and corner, etc, etc. In my (limited) racing experience, I've seen people run 40' from the inside of a corner on the complete opposite road shoulder. Recognizing that my results are just a sample of one, here are some of my Garmin vs race distances, I'd call it pretty darn accurate: Office race distance / Garmin measured during the race 26.2 | 26.37 13.1 | 13.28 13.1 | 13.25 (same course as 13.28 above, different year) 10m | 10.04 10K | 6.27 10K | 6.25 10K | 6.23 5m | 5.04 5m | 5.02 (same course as 5.04 above, different year)
                      I will be the first to admit that these GPS devices are pretty amazing (I have a Garmin 205). It's remarkable that they can come as close as the numbers on your list. However, .02 for 5 miles = 7.2 seconds at 6-minute per mile pace. At 8-min pace it becomes almost 10 seconds. This is quite significant, imo, and is multiplied as the distance increases. They are more than adequate for measuring practice routes and timing most workouts. However, when it comes to race distances they are just not precise enough. The course certification process is much more reliable, imo. I spent more than a half hour last spring talking to a USATF course measurer and he was very convincing.
                      Age 60 plus best times: 5k 19:00, 10k 38:35, 10m 1:05:30, HM 1:24:09, 30k 2:04:33


                      an amazing likeness

                        It's remarkable that they can come as close as the numbers on your list. However, .02 for 5 miles = 7.2 seconds at 6-minute per mile pace. At 8-min pace it becomes almost 10 seconds. This is quite significant, imo, and is multiplied as the distance increases. They are more than adequate for measuring practice routes and timing most workouts. However, when it comes to race distances they are just not precise enough. The course certification process is much more reliable, imo. I spent more than a half hour last spring talking to a USATF course measurer and he was very convincing.
                        Don't get me wrong -- I agree with your point on certified course accuracy and all the courses I listed are certified, so I view the course length as the reference measurement and the Garmin as the distance I ran, +/- the accuracy of the data recorder and the parsing software. My point is really just a slightly different repeat of Run2Win's reply to the original post - the reason the races measure long on our Garmins is because we run them longer than the line used to layout the course, plus there is a small bit of fudge factor in the GPS. I disagree that the fudge factor in the GPS is the major cause for race distances measuring long via GPS, and showed my data in support of that.

                        Choosing my words carefully has never been my strength I've been known to be vague and often pointless


                        Feeling the growl again

                          Right on their website, Garmin claims 99% distance accuracy for the 201. I don't know what the newer versions are, but 99% as I stated earlier leaves an error of over .25 miles during a marathon. That's 2 minutes or more error for most people. Now add on top of that not running the tangents perfectly, and it is easy to see how it can read 26.6 or 26.7 no problem! Case in point for GPS technology. I have a Garmin handheld unit, which has a much better antenna than the running versions. Recently I was in the mountains of western Montana and used it to mark a waypoint next to a tree where I had hid elk quarters from scavenging birds. I synched it up, and it tells me how well it is synched which the running versions do not -- accuracy +/- 75 feet. This was on top of a virtually treeless mountain at 7000 feet with a full view of the sky and solid lock on 4 satellites. The next day I came back and synched it up again -- accuracy +/- 86 feet locking 4 satellites. It got me within about 80 yards of the tree I was going to find, I still had to disregard it once I was in the vicinity and locate it myself. Think about the error that +/- 75-86 feet can mean in running, and how a running watch must take a whole bunch of measurements, not just one point measurement like I was in this case. The best example is I have seen in the past people post the track their garmin recorded plotted on some computer program overlaying an aerial map. The deviation from the road they were running on in a straight line was sometimes quite dramatic.

                          "If you want to be a bad a$s, then do what a bad a$s does.  There's your pep talk for today.  Go Run." -- Slo_Hand

                           

                            Right on their website, Garmin claims 99% distance accuracy for the 201. I don't know what the newer versions are, but 99% as I stated earlier leaves an error of over .25 miles during a marathon. That's 2 minutes or more error for most people. Now add on top of that not running the tangents perfectly, and it is easy to see how it can read 26.6 or 26.7 no problem! Case in point for GPS technology. I have a Garmin handheld unit, which has a much better antenna than the running versions. Recently I was in the mountains of western Montana and used it to mark a waypoint next to a tree where I had hid elk quarters from scavenging birds. I synched it up, and it tells me how well it is synched which the running versions do not -- accuracy +/- 75 feet. This was on top of a virtually treeless mountain at 7000 feet with a full view of the sky and solid lock on 4 satellites. The next day I came back and synched it up again -- accuracy +/- 86 feet locking 4 satellites. It got me within about 80 yards of the tree I was going to find, I still had to disregard it once I was in the vicinity and locate it myself. Think about the error that +/- 75-86 feet can mean in running, and how a running watch must take a whole bunch of measurements, not just one point measurement like I was in this case. The best example is I have seen in the past people post the track their garmin recorded plotted on some computer program overlaying an aerial map. The deviation from the road they were running on in a straight line was sometimes quite dramatic.
                            Wrong. The running versions (at least the Forerunner does) DO tell you how well it is 'synched' as you call it. You can display it as one of your data fields. You may have an old GPS unit (not using the newer Sirfstar II chipset) because best accuracy of a Forerunner 205 GPS I've seen is +/- 14 feet (and this is what I usually get during my runs on open trails). Can be much worse than that if you're in a downtown area or a heavily forested area or mountains etc. The old 201/301 version - fuggeddabout accuracy, far, far worse. And the bulk of the mismeasurement of race course lengths by the Forerunner IS GPS inaccuracy, not mis-running the tangents.


                            an amazing likeness

                              And the bulk of the mismeasurement of race course lengths by the Forerunner IS GPS inaccuracy, not mis-running the tangents.
                              Do you have any supporting information for this? I'd sincerely like to learn what supports this as the case over the runner's line not being the actual, measured course route.

                              Choosing my words carefully has never been my strength I've been known to be vague and often pointless


                              I've got a fever...

                                And the bulk of the mismeasurement of race course lengths by the Forerunner IS GPS inaccuracy, not mis-running the tangents.
                                What information do you have to support that? MTA: Apparently MilkTruck and I think alike. Tongue Now, I'll admit up front that I don't have data of any kind to support this; however, my impression from reading many posts about this topic is that the majority of users who have posted Garmin vs. course discrepancies on RA report that the Garmin measures longer than the course. This would indicate to me that the tangential component is at least a fairly significant one. Otherwise, you'd observe errors more equally distributed long or short. It would seem that both GPS inaccuracy and poorly run tangents come into play. Which is more dominant is anyone's guess. The bottom line is that the Garmin is a great tool, but it's not the be-all end-all of measurement. And it won't make you kick and pass that runner ahead of you in the last 100 yards of the race. You've got to do that yourself.

                                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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