How does Garmin predict the finish time for a race?

9076053 1 month ago

Hi!

I have a ForeRunner 965 and I'm preparing for a marathon this year. It will be trail-running. I think the predicted finish time is way more optimistic then it should be.

Today I ran about 24 km/600m ascent. It was 02:55 hours.

The race that I have set up is 43km with 1.200m ascent. Garmin predicts 05:13 time for me which is simply not going to happen. I have a feeling since a long time that the race prediction doesn't account for the ascent, just the distance. Is that a fair assumption? Or what else could explain this behaviour?

Thanks!

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0 flocsy🤠 1 month ago

I almost entirely run on flat surface and the predictions are always too optimistic for me too

0 morey000 1 month ago

How does it predict finish times? I think the answer is “poorly”.
But also- training paces do not reflect race paces. What you did do, and what you can do, are two very different things

0 flocsy🤠 1 month ago in reply to morey000

Well it depends...

There are people who claim it's pretty accurate. They usually run much faster and longer than I do. Maybe that's part of it.

Maybe my hr values aren't set correctly (they are set automatically by the watch, so it's not an acceptable excuse...)

Maybe it's like horoscope? They display some random number and it is accurate for 1/3 of the population, overly optimistic for 1/3 and too slow for 1/3. Who knows...

0 9076053 1 month ago

Thanks for the input, seems like it's not something that I do wrong

0 jkissane_ 1 month ago

I have my GC account connected to the Runalyze site & the 5k prediction on the watch & the site are pretty close (20:37 vs 20:42). My best 5k time this year is 20:58 at a parkrun so if I was in a race the prediction might be possible (on a good day!).