Race Predictor - Way off?

I'll just chime into confirm that pretty much everything everyone's said is correct.

It's a pretty dumb feature, dumb in the sense that there isn't any special intelligence built into it. Your VO2max is fed into a lookup table to fetch your predictions. That's about it.

Confusing the matter is that there is an underlying assumption that you have the training in your legs for the particular distance listed... and if you aren't, say, in marathon shape and start training for one, then your aerobic performance capacity (VO2max) will almost certainly improve over the course of your training efforts. So, what sense that allows you to make of your Race Time Prediction, I'm not sure. If you aren't trained for a race, then you almost certainly wouldn't actually be able to hit your prediction... but if you were to train for the race, then your predicted time would also change.

Great, eh?

There was a huge amount written about this a few years ago when it was launched on the 620.

A couple of things that many noticed are:

1. Your max HR might be too high and your VO2 score a little too high. Manually take off 5 beats off your Max HR and your score might come down and your times
become more realistic.

2. Even then you’ll probably find the 5 and 10K times fairly realistic, the HM time a bit of a stretch and the marathon time very very aggressive.

Also as as others have mentioned it’ll a simple look up table. The watch has no idea if you’ve been training like a Kenyan or you’re running 30m/50K a week.