20.32: Race prediction horribly inaccurate.

Race Prediction for a half marathon: 1:41:35. This is quite impossible, since it would imply running nearly at my max. heart rate the entire time.

I just did a half marathon this weekend where I was pretty much in my zone 4 the entire time, so I really can't push any harder than this. I finished in 1:57.

Still, the race predictor happily states I should pull off a HM in 1:41.

NO. My watch KNOWS my HR zones. My watch KNOWS I just did a race in that time and saw how badly it went. So why won't it adjust the race prediction to an actual valid prediction? This is just incredibly demotivating.

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  • NO. My watch KNOWS my HR zones. My watch KNOWS I just did a race in that time and saw how badly it went. So why won't it adjust the race prediction to an actual valid prediction?

    Heart…

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  • Yes. I've had a lactate threshold and max HR test done a few times already so my HR zones are 100% correct.

  • NO. My watch KNOWS my HR zones. My watch KNOWS I just did a race in that time and saw how badly it went. So why won't it adjust the race prediction to an actual valid prediction?

    Heart rate zones are irrelevant to the metrics used for the Race Predictor: VO2 Max, recent training history (mileage, pace, et.)

    I know it is not intuitive, but a race is just another set of data used by the race predictor, just like any other run.

    I noticed as well that the race predictor became too optimistic for me after the recent optimizations by Garmin. Earlier this year, it was as accurate as Stryd's race predictions.

    As a user, there is not much you can do except feeding the watch with data as accurate as possible:

    - accurate Max HR and recent lactate threshold test

    - chest strap every time

    - best GPS settings and/or calibrated pod

    - variety of efforts: once every couple of weeks for example, run a suggested workout, but run your maximum steady pace for the intervals of the workout, instead of the suggested HR or pace target. Over time, across workout styles, this will build a more accurate picture of your performance (actual and potential) for various distances.