drove my car to get feel 4 Half Marathon course and I keep getting 13.24 on odometer and GMAP pedometer instead of~13.1?

I believe in order to certify a course you have to add a distance, of .1 miles or something like that.

it is just tangents.

If you run the way you should run a race (shortest legal route possible) then you will run a Half Marathon

stuck with match.com wrote:

I believe in order to certify a course you have to add a distance, of .1 miles or something like that.

How about you don't say things if you aren't qualified. Any statement that ends with "or something like that" should probably just be kept to yourself in the first place.

USATF course certification process:

They use a working constant of 1.001. That would change a 13.100 mi course to 13.113.

It's likely that your extra distance is due to not running tangents.

How about you shove it up your ass, you pompous prick?

(I say that only because I am qualified to do so.)

Mystto wrote:

Drove my car to get feel 4 Half Marathon course and I keep getting 13.24 on odometer

The accuracy of your odometer depends on tire pressure, tire wear, etc. A car odometer is simply not an accurate measuring device.

OP, if the course you're looking at is certified, that's all you need to know about the *total* distance; but you're right, intermediate distances are sometimes not so accurate. If you're going to try to figure out where the mile splits are (using your odometer/pedometer), you'll need to allow 1.01 of *your* miles for each certified mile.

...assuming that turns/tangents are not a major factor, of course.

[BTW a half marathon is actually just under 13.11 miles. Another hundredth of a mile is not exactly killer, obviously: three or four seconds for most.]

Thanks guys. Do you know why GMAP-pedometer (using Google maps) would be off and getting the 13.24ish? A lot of us use GMAPs to get feedback on our runs. Does that measure distances as though you were a car???

Benji Durden does it this way - no doubt.

stuck with match.com wrote:

I believe in order to certify a course you have to add a distance, of .1 miles or something like that.

Hey, when you drove the course did you needlessly steer the wheel back and forth like those morons in the movies do? That's prolly what added the extra distance right there.

drivers ed wrote:

Hey, when you drove the course did you needlessly steer the wheel back and forth like those morons in the movies do? That's prolly what added the extra distance right there.

haha nope. but 13.11 * 1.01 = 13.2411???

The course must be AT LEAST 1.001 times the nominal race distance. So if your course is even over a tenth of a mile too long, like you suggest, it's still certifiable.

Certifiable meaning sometimes that it's too bad if the times are way slower than they should be because it's wrong, but we know it's got to be at least the official distance so we don't care?

Just trying to understand

Are your odometer and pedometer update?

im using that and the car odometer as a backup which gets pretty much the same as GMAP in most cases

Mystto wrote:

Drove my car to see a USATF certified Half Marathon course and I keep getting 13.24mi instead of 13.1 on GMAP and my car? anyone with similar experiences?

I'm guessing this is obviously in part because of cutting tangents and stuff on the roads but still I didnt think it'd be off at some parts? before u get mad at me, obviously being off a friggin 10th of a mile is nothing but if I'm trying to monitor my pace along the way and maybe half of the mile markers do not correspond very well to the spraypainted lines, it sucks to find myself slower than i expected at each mile marker because they may be off. who knows?

Another one for the Letsrun Thread Hall of Fame. I can't believe there's anyone who believes that their cars odometer or "gmap" are accurate measuring devices?

The mile markers are probably accurate, but for argument's sake lets say that they are not correct. What difference does that make? This is extraneous information that has nothing to do wit your performance, and is a distraction from the task at hand. Focus on racing and all will be fine.

I would just line up .13 miles in front of the official starting line. If someone says anything, explain the situation to them. They'll appreciate your help.

It's good that you figured this out *before* the race. I usually just curse out race officials when I find my Garmin reading long after the race.

malmo wrote:

The mile markers are probably accurate, but for argument's sake lets say that they are not correct. What difference does that make? This is extraneous information that has nothing to do wit your performance, and is a distraction from the task at hand. Focus on racing and all will be fine.

it makes no difference other than that i may be able to run a faster "half marathon" on a real half marathon course instead of one that is long because it was too much trouble to get it accurate and so they had to be to be sure it was AT LEAST the official distance...

Mystto wrote:

it makes no difference other than that i may be able to run a faster "half marathon" on a real half marathon course instead of one that is long because it was too much trouble to get it accurate and so they had to be to be sure it was AT LEAST the official distance...

For the love of god...a certified course IS accurate. Why on Earth would you ever believe your cars odometer gives an accurate measure?

Yes, car odometers are easily accurate well within this range.

For courses to be certified, they allow for an uncertainty of .1%, i.e. between .999 and 1.001 times the distance. They don't have to be longer than the distance.

My guess is you just aren't sure exactly where the start and finish line are? Like, maybe it tells you where they are, but when you get to the course on race day the start line mat might be farther up than you thought, or something.