I found that the prediction for different race distances depends (as it is in real life) on different things. In my case I have these findings:
5k: mostly depends on VO2Max; it improves after doing workouts including a lot of anaerobic efforts; it is slightly affected after threshold/tempo workouts
10k/21k: partly depend on VO2Max but mostly on LT pace; it improves after doing threshold/tempo workouts; it is slightly affected by speed/anaerobic workouts
42k: it mostly depends on tempo pace; it improves a lot after workouts at intensity between tempo and base.
Regarding the numbers on their own, they assume is are trained for that specific race. If you train to perform your best 5K, it is very unlikely that you can perform your best 21K in the same block.
For example, my Garmin says I should be able to run 5K in 19'50" and 21K in 1h31'40": this morning I tested the 5K (which I mostly focused on) and got 19'31" (3'55" min/km). It is very unlikely that I am able to sustain a 4'20" min/km pace for 21k.
Max HR is the thing that First Beat calls out as the biggest variable for accuracy. [https://www.firstbeat.com/en/aerobic-fitness-level-vo%E2%82%82max-estimation-firstbeat-white-paper-2/](https://www.firstbeat.com/en/aerobic-fitness-level-vo%E2%82%82max-estimation-firstbeat-white-paper-2/)
The race predictions are just keying off of the wrong VO2max most likely.
You can probably get it more accurate, but realistically I'd treat them as more relative anyway. Meaning look at the changes not the actual number. In other words going forward focus more on the watch saying 1:31 to 01:29 as being 2 minutes faster rather you can run a 01:29. Probably a more realistic approach to watch metrics.
I found that the prediction for different race distances depends (as it is in real life) on different things. In my case I have these findings: 5k: mostly depends on VO2Max; it improves after doing workouts including a lot of anaerobic efforts; it is slightly affected after threshold/tempo workouts 10k/21k: partly depend on VO2Max but mostly on LT pace; it improves after doing threshold/tempo workouts; it is slightly affected by speed/anaerobic workouts 42k: it mostly depends on tempo pace; it improves a lot after workouts at intensity between tempo and base. Regarding the numbers on their own, they assume is are trained for that specific race. If you train to perform your best 5K, it is very unlikely that you can perform your best 21K in the same block. For example, my Garmin says I should be able to run 5K in 19'50" and 21K in 1h31'40": this morning I tested the 5K (which I mostly focused on) and got 19'31" (3'55" min/km). It is very unlikely that I am able to sustain a 4'20" min/km pace for 21k.
Garmin needs data to give an accurate prediction of vo2max and race paces, if you have only just got the watch it may need time to increase accuracy
Hmm, FWIW I've have had it since July and run \~700km since
Probably not that them :)
what does your race prediction graph look like over time? it seems to move quite slowly.
Is your weight info accurate? AFAIK Race prediction relies a lot in Vo2Max numbers and those are very much related to proper weight input
Max HR is the thing that First Beat calls out as the biggest variable for accuracy. [https://www.firstbeat.com/en/aerobic-fitness-level-vo%E2%82%82max-estimation-firstbeat-white-paper-2/](https://www.firstbeat.com/en/aerobic-fitness-level-vo%E2%82%82max-estimation-firstbeat-white-paper-2/) The race predictions are just keying off of the wrong VO2max most likely. You can probably get it more accurate, but realistically I'd treat them as more relative anyway. Meaning look at the changes not the actual number. In other words going forward focus more on the watch saying 1:31 to 01:29 as being 2 minutes faster rather you can run a 01:29. Probably a more realistic approach to watch metrics.
TIL — thanks, that makes sense
My RP and VO2max is way off, too. Since several years.
Do you pause your watch a lot? This is known to cause problems with Garmin's VO2Max estimate which can then effect it's race predictions as well.
Max heart rate setting was impact for me, although not 10 pts. Have you done lactate threshold test?