-
They've been vaguely accurate if I take away 2 from the VO2max score that the Garmin is predicting and then look up that figure in the VDOT tables (or 3 or 4 for the longer runs, see below). That seems to be the suggestion on the Garmin Forums too. So if you do a parkrun as fast as you think you can it merrily tells you your predicted time is a couple of minutes faster.
If you're overweight then keeping up with the figures on the VDOT table is nigh on impossible as the distances get longer. I was running parkrun in 24:24 but there was no way I could do a 1h53 half (best at that time was 2h06, sure I could have pushed harder on that half but not 1min/mile faster!). As the weight dropped off (and fitness improved) my times for the longer runs were dropping faster than the improvements on the shorter runs, I guess that at some magic weight I'd fit the VDOT curves exactly (and that's probably 60kg for me, which I will never ever see).
Most of the time the Garmin's figures are way out because it has an inflated sense of ones HR[sub]max[/sub]. I track my 5-a-side via a 'Run' on my Garmin and my HR can easily get above 200bpm during a game, never seen it that high even sprinting near the end of a parkrun. It must just think I'm being lazy when I go out for a steady/fast run if it's using the info from the former to predict the latter.
The algorithms in the Forerunner 935 seem a bit better (compared to my 920xt), at least it's also basing its predictions on its guess at LTHR (which seems to be relatively accurate).
Anyway, it's mostly useless whilst I'm still lardy. I'll pay some proper attention to it when I'm under 80kg.
Might look out for some cheap (ha!) Garmin scales as I keep forgetting to update GC with daily weights.
You are reading a single comment by @Greenbank and its replies.
Click here to read the full conversation.
Greenbank
Garmin VO2s and predicted race times are just a nonsense to be honest. Not worth basing anything on.