VO2 max

Riding as fast and hard as I can sometimes takes my Garmin estimate of VO2 down a notch, then it comes back up after the next ride if it's a little bit more mellow. I've been doing mostly threshold lately, yesterday I went out and tooled around in Z2 for an hour and came home to a point higher value. I know it's a version of PWR:HR, and the hard rides mean a high HR, I've always assumed that's why I see this.

For running they use pace in place of power, and the white paper says they do a lot of filtering of the data to only look at the points they consider most reliable. I don't know what they're doing on the bike but it's probably also not something you'd do on the back of a napkin.

I had some research notes from the past, don't know if in current FirstBeat whitepaper, that shared they took the basic research in this study and tweaked it.

www.ncbi.nlm.nih.gov/pubmed/2287267

The PAR table of frequency and time of workouts came from that, with additional levels they added.
Of course you can pick your level in GC settings - but pretty sure current devices are just doing a rolling avg of the workouts it knows about.
And instead of specific level numbers, probably a continuous range.

So to me a current short workout being examined for time only, replacing a past one that may have been longer - makes sense to drop the VO2.
Age does make a difference, again could do whole number age or continuous range.

Here's the formula as it used to be. And when Garmin first would show it's estimated VO2max, it matched using the figures I thought they were probably using. Haven't compared or done the math in ages though.

=Gender M=1, F=0 * 10.987 + 56.363 + 1.921 * PAR value from 10 level table - 0.381 * Age - 0.754 * BMI

I guess the kicker is how far back into workouts are they going to establish those PAR table levels.
And of course other tweaks since way back involving watts or pace.

See if this table shows up correctly.

sijomial wrote: »

dewd2 wrote: »

During my morning run yesterday the topic of VO2max came up. The guy I was running with commented that Garmin gave him a number in the 40's. Garmin gives me numbers generally in the mid 50's. Knowing that my friend I was running with could kick my *kitten* any time he wanted made me think.... He has been running trails with ungodly amounts of vertical gain for the past 8 weeks and I have started to add speed work back into my routine. I would bet the different approaches we are using to training is the reason because the numbers make no sense any other way...

ETA - To me this makes the measurement only useful if you are doing the type of training that allows it to be measured more accurately. Slow trail miles (even extremely challenging ones) will not produce an accurate result. YMMV.

@dewd2

Joe Friel touches on an interesting subject in book I read earlier this year (Fast After 50)....

VO2 max is only a measure (or estimate in Garmin's case) of oxygen uptake and not directly a performance metric.
Apparantly Olympic marathon winner Frank Shorter had a really ordinary VO2 max (in comparison to other elite runners) but appeared to use that oxygen far more efficiently than other runners judging by his speed and results.

Would be a fascinating comparison if you and your friend were following the same programme and at same point in the same program.

In Garmin's case I see the same thing as you in that long slow rides skew the VO2 estimate downwards and short intense rides skew it upwards. My score can zigzag quite nicely especially indoor training with less variables when clearly my actual oxygen uptake ability isn't changing day by day. The extended trend seems reasonable/believable for me though.

Yes, the whole running economy thing. I'm not sure we'd ever follow the same program since he is primarily a trail runner and I tend to run road races more.

I really should get that book but I'm not sure I want to admit I'm over 50 yet.