A very helpful response that I think highlights my naivety in standalone run races. Thanks to everyone else who has also responded, certainly shows a difference of opinion.
This has only been my fourth standalone half marathon over the years (never done a standalone full or 10k even), and the first one in which I’ve actually focussed my training to try and achieve a time. I’m a pretty well versed triathlete and just accept that the distances across all distances are never spot on, so my PRs are always relative to the course. I kind of assumed that the half marathon would be spot on and my gps, which has been accurate with wheel measured 5k Park runs, would reflect this, so I was disappointed when I hit the required average pace times and was just over the chip target, having based my training on my watch.
I’d read that running tangents was important, and being an out and back course along a river path Im pretty sure I ran them. Having reviewed the course tcx file, the dog leg at the second turnaround (the race went back past the finish to turn around again to make up the distance), was different to the course I did. This “may” have added some, but I don’t think enough to account for the 1’13 I was over.
What I have learnt is that when I try again, maybe in four weeks on a different course, I’ll try to hit the splits several seconds quicker, to account for extra gps distance. So basically run quicker!
I already responded yesterday with comments including “You are only answerable to yourself. Pick one and move on… does it actually matter? … if the times were the other way around, chip<90min, GPS>90min would you still be here asking which to use…”
But I’d like to add something. Many of the responses are discussing the potential difference in accuracy between GPS data and certified measured courses, and between certified measured courses and claimed distances with dubious relationships to reality (IM etc). While this is somewhat legitimate, there’s a very fundamental detail that several have alluded to by talking about how they run a course, but none have actually discussed directly. Your GPS device, and the person out measuring a course with a trundle wheel are not attempting to measure the same thing. It’s not just a question of accuracy, but also the quantity being measured. The GPS device is measuring it’s trace over the ground. The wheel, as I understand it, is used to measure the shortest line around the course within the designated boundary. One is the shortest distance you could potentially run, the other is the distance you actually run. Even if perfectly accurate measurements were possible they’d be different. So before even considering accuracy of measurement you must decide what your PB (or PR in US) means. Do you consider your PB to be your best time for a route of that stated distance in a race, for running that actual distance in a race, for running that actual distance under any circumstances, or a route of that stated distance IF the distance is certified/seems correct. I don’t think there’s a right or wrong answer. I do think you should be pretty consistent, and honest with yourself. You’ll never have an exact, fully verifiable measurement of time or distance, so best to just decide what your own rules are and stick to them. But mostly, don’t take the numbers too seriously. They really don’t matter very much.
I guess the reality of all this is that people can claim whichever they want and others will acknowledge that claim whichever way they want.
Then you have the phenomena of the Runner who is asked for their marathon PB, and they’ll respond with something like “I ran 3:20 at Boston one year, 3:22 at NYC, but my best is 3:18”
They just* had to* get Boston and NYC in there, instead of simply answering the question
I’ve had this happen to me before and I’ve overheard the same at more than a few Expos/Packet Pick-up
It points back to “You’re not a REAL Runner until you run a marathon, especially Boston”
First off, not a runner. Cyclist that does running in the off season.
I scope out an out/back usually on a paved greenway in a straight section. I’ll plan a route in Strava to correspond with the installed mile markers. I only care about 1mi, 5k, 10k, or 1/2. So the mile markers give a sanity check against both the Strava planned route distance and the gps. Otherwise, if I really wanted one they hold “open track night” now at the local middle school. I’d be slow as crap compared to those folks but it would be a more official distance.
Otherwise in the spirit of no downhill or downwind only time trials for PR’s, the runs are out/backs. IDGAF about downhill downwind BS.
I even claimed a 1/2 PR by my house last winter despite a 1 min delay crossing a road with a light. The route was hilly looped route, so take out the 800 feet of elevation in 13mi and I get my minute back. I’m not paying to go do a run event as it isn’t my sport, so that’s the best I’ve got. I just wanted to break 2 for a 1/2 and did so by a good bit, so marked that off the list.
I typically go with my GPS time. Ive seen some strange results from chip times that make me leery of them.
For example I finished a bike section of a tri with an average speed of 29.7mph and the guy that finished ahead of me was clocked doing 31.3mph.
Now Im a pretty strong rider but not a chance in hell I did 29.7 for the whole race.
My Garmin had me at 23.4mph which is consistent with my other races of similar distance. I don’t always start and stop my watch perfectly going in and out of transition but its a lot more realistic then 29.7.
Ive similarly seen problems with swims so not I just rely on my Garmin.
You do realize that the chip is not giving you that pace/avg speed, correct? The chip gives you the time elapsed, the pace is a calculation based on the chip time and the distance that is entered by the timing company. Perhaps they entered 15 miles for the bike when it was only 12 or something like that. In that case, say you rode the course in 30 min, race timing is going to give you a pace of about 30mph but your actual pace is more like 24mph, the time for the split is still the same at 30 minutes either way.
Your GPS time should be the same as the chip time, would only differ if you started the GPS before or after crossing the timing mat.
OP, take this thought over to Letsrun and see what they have to say.
Funny that even CyclingNews is confused on this topic.Yates appeared to run a consistent pace throughout, averaging four minutes 14 seconds per kilometre for the 42.195-kilometre course.
Those statistics might not be totally reliable, however. Yates took a photo of his sports watch, which was tracking his run and gave a time of 2:58:08 and a total distance of 42.65km. That would make his effort even more impressive, with an average pace of 4:11/km.
Again, a difference of 1-2% should be expected.
While it doesn’t really matter (frankly, it’s not that important in the grad scheme of things), GPS is not as accurate. Just take the fastest time:)
Food for throught;
Why Your GPS Lies.
In GPS we trust.
IIRC, there was a guy who tried to sue a Marathon because his GPS distance/time was good enough for Boston, but his Chip time was not. Can’t find it online, but I think his case was laughed out of court.
Chip time 100% (especially if you’re on a certified course). GPS watches are notoriously inaccurate (unless you’re running in a straight line, with no clouds and no high buildings/trees around). If you’re running on a certified course the distance was the distance. You may have run some extra, maybe not taking the most optimal tangents or something like that but I think that difference would be much less than GPS error. I’ve seen people run 11 laps on the track and claim a 5k pb because their gps watch said it was 5k. (eyeroll). Congrats on your run though!
My running heyday was well before gps, so for me, I would not count it. For me the time is start line to finish line (ie chip). I find my gps devices are not accurate enough to claim a PB, and to use one to “override†the clock wouldn’t give me the satisfaction of a PB.
That said, back then if I hit a short course I would not have known it, so it isn’t really all that “better†to rely on chip only.
All in all I was a track guy, so I ignored most road times anyway.
Also, old school and would not count it. Your race time is your race time even if it’s long. On the flip side, you don’t get to count a race as a PR if it wasn’t certified. Ex. My 5K PR is 14:50 certified. I ran 14:35 in a road race that was not certified. Tough luck, it was probably short. As a rule of thumb if it isn’t certified (and has the USATF cert # to back it up), just figure it’s short. If it is certified, it HAS to be long to allow for a cushion in case of a record requiring recertification. Track times also count, of course!
