Do you monitor your HRM or pace when running races?

NorthCascades

MeanderingMammal wrote: »

On the road or trail the GPS related pool of error is less significant, and whilst a footpod might give a better measure of short term pace, I'd question whether it makes enough of a difference to be meaningful.

It certainly depends a lot on which road, which trail, and which GPS. Even if you really really really want to be right here, a great many experienced runners disagree with you.

MeanderingMammal

dewd2 wrote: »

NorthCascades wrote: »

Foot pod is more accurate than GPS.

I will have to dig for the stats but I'm sure I read that a footpod is almost as accurate as GPS on flat surface. As soon as you introduce the outdoors, it starts to fail (unless your stride stays exactly the same running over obstacles as it does when running on a flat track).

fwiw the positional error for consumer grade GPS can be anything out to 2metres at 80%. If you consider that error can be in any direction then worst case you've got a 4metre discrepancy between data points. Over an endurance race that'll probably net off, but it can depend on latitude, elevation, obstruction of the space vehicles, vegetation, humidity and microwave scintillation.

Diff GPS can reduce that compounded error down to less than a metre, and should reduce the effect of atmospherics.

I've seen issues in Iraq from atmospherics on the use of GPS and we ended up doing optical surveys to position equipment given the problems of the constellation

MeanderingMammal

NorthCascades wrote: »

MeanderingMammal wrote: »

The point about materiality is more about whether the "more accurate" is actually meaningful in anything other than a lab.

Like I said, there's a long tunnel on a popular running route near me, GPS measures it as zero feet. A foot pod is certainly more accurate than that, and I can tell you for a fact that tunnel isn't a lab. So it's pretty much settled.

So your exception case rulez.

cool

CincyNeid

Now I understand this post is primarily referring to running. However this happened yesterday and will give you a exact reason why Runners use Cadence Pods and Cycling use Speed Sensors to speed v. distance.

Yesterday I took my Aventon Mataro out for a 26 mile blast. The Bike is a fixed gear bike. Which means when the pedals are spinning the back tire is spinning at the same exact rate. The bike cannot coast. The speed and cadence should be an exact 1:1 relation. If I'm spinning at x RPM then my bike should be going X mph. However I didn't have my Speed Sensor installed on this bike yesterday. I relied on the GPS/GLONASS instead of swapping my Garmin Speed Sensor over to the bike. And this happened.






according to this chart I was actually going slower at a higher RPM. 18.8mph at 92RPM vs 20.1mph at 79RPM.

If I would of had a Speed Sensor on this bike the Speed would of matched the Cadence to a T. But because I was under a heavy Tree Canopy it took the GPS/GLONASS a few seconds to catch up which throws one's number off.

Same thing with runners. When you go through a tunnel, under heavy clouds, under a heavy tree canopy the same thing will happen when you're running.

NorthCascades

MeanderingMammal wrote: »

NorthCascades wrote: »

MeanderingMammal wrote: »

The point about materiality is more about whether the "more accurate" is actually meaningful in anything other than a lab.

Like I said, there's a long tunnel on a popular running route near me, GPS measures it as zero feet. A foot pod is certainly more accurate than that, and I can tell you for a fact that tunnel isn't a lab. So it's pretty much settled.

So your exception case rulez.

cool

When you have some more experience I'm sure you'll figure it out.

dewd2

Assuming I can remember I will wear my footpod for my marathon in November. The course is a Boston qualifier so I trust that it will be accurate. I did not wear it for my half yesterday and my Garmin Forerunner 630 gave me 13.15 miles. Since this course is also part of the full marathon I will trust that it is accurate. Maybe I will get a chance to run it again with the footpod as well. Not sure I'll be able to work that in...

FWIW, I did notice my watch buzzing at me for each mile just before the actual markers. It was consistent so I assume if it missed anything it was at the beginning of the race.

MeanderingMammal

NorthCascades wrote: »

MeanderingMammal wrote: »

NorthCascades wrote: »

MeanderingMammal wrote: »

The point about materiality is more about whether the "more accurate" is actually meaningful in anything other than a lab.

Like I said, there's a long tunnel on a popular running route near me, GPS measures it as zero feet. A foot pod is certainly more accurate than that, and I can tell you for a fact that tunnel isn't a lab. So it's pretty much settled.

So your exception case rulez.

cool

When you have some more experience I'm sure you'll figure it out.

Given that I've only got a BEng and MSc in Control Engineering I might need to go and do a PhD in it...

Vladimirnapkin

I generally train by pace, but use HR for analysis after the fact. It can give you clues to why things happened the way they did, in a race or workout. Also, as I get into better shape, I find myself looking at my watch less and less, and run more by feel. When I do this, I find myself going faster, for some reason. When the weather is hot, I may monitor my HR during long efforts as a proxy for hydration. (Your HR is inversely proportional to your blood volume, which can decrease as you get dehydrated.)

Humorously, as my eyes get crummier with age, I find the watch information to be a lot less useful. (I can't read it!)

Finally, doesn't your Fenix have a cadence monitor built into it? My Garmin 220 does and can do a pretty good job of estimating distance and pace when I lose GPS signal.

litsy3

Recently I went for a 16 mile run with my friend but when we'd finished her garmin said 16.1 miles and mine said 15.85. Luckily I didn't care (except I did a bit because I ran up and down the road till it was a round number ). But in certified measured races measured with a Jones counter I'm more inclined to trust the course measurer than my GPS, which thinks they are all short. And on the track obviously I'm more inclined to trust the fact that it's a 400m track. Easy runs don't matter, because there are no prizes for winning those.

niblue

Bikes don't change stride in the middle of a run.

My bike has a speed sensor but it given it links to a GPS then it doesn't really tell me anything useful when cycling outside (although it is useful on a turbo trainer). That speed sensor also gives cadence though, which is useful (and more of an analogue to what a footpod gives you when running).