Garmin VO2 Max Vs Anaerobic Training Status

[bbarrera]

AFAIK, for cycling indoors or outdoors it only uses power and heart rate. For example from the white paper in the link you provided:

[mcalista]

@stevepetts372

It seems their algorithm relies on comparing heart rate to speed. Does that create problems for trainer work? In ERG, you can sit at the same heart rate and significantly change recorded speed just by changing gear

The Firstbeat algorithm uses speed v HR for estimating running VO2Max, and power v HR for cycling VO2Mqx

[stevepetts372]

Thanks. If possible, can you provide a link to where that is stated?

[bbarrera]

Right in the Garmin manual. For example:

https://www8.garmin.com/manuals/webhelp/edge530/EN-US/GUID-6731AE5F-8A9A-450D-9BD3-0C2BBA056DA0.html

[mcalista]

I did go looking for a reference before posting, but a number of the supporting documents/explanations that I previously read are no longer on the Firstbeat website following their partial acquisition by Garmin. (the residual Firstbeat is now focussed on coaching and corporate wellness.).

Have now gone looking on the Garmin website. Try this. What Is VO2 Max Estimate and How Does It Work? | Garmin Customer Support

[stevepetts372]

Cycling activity must be 20 minutes in length or longer without stopping

• Heart rate data from either a built-in optical heart rate sensor or from a chest strap
• Heart rate must be elevated to at least 70% of your maximum heart rate for at least 20 minutes continuously
• Power meter is required reference

I think this will do! Thanks

[Jackc70]

So, in simple terms, Garmin looks not at your zones, but how your EPOC was affected by each workout, and gives you what it thinks is the level of effort for that workout?

So in my specific cases, my last workouts have, according to Garmin, been harder than they are prescribed as being (despite my HR being neither too high or too low) and I can assume then that this is down to fatigue so I should take some recovery time?

[bbarrera]

As best I understand it, in simple terms, Garmin is:

• performing real-time Machine Learning analysis of your heart rate, heart rate variability, and power

in order to:

• score the workout in terms of impact on aerobic and anaerobic fitness
• map the workout’s primary benefit to Coggan zones: recovery, endurance, tempo, threshold, vo2max, anaerobic, and sprint

(or stated another way, the workout’s impact on key training adaptations)

and more specifically that involves:

• real-time estimation of variations in VO2max (against baseline VO2max) during the workout
• real-time estimation of your post exercise oxygen consumption (EPOC) during the workout
• real-time segmenting and classification of unstructured/structured ‘intervals’ as either aerobic (>3 min) or anaerobic (10-sec to 2-min)
• at the end, scoring the aerobic and anaerobic in terms of adaptations, for example an Aerobic score between 4.0 to 4.9 is a strong signal to drive aerobic adaptations
• at the end, translating the aerobic/anaerobic scores into a primary benefit of training, by Coggan zones, for example a session primarily improved threshold, or base, or vo2max, or anaerobic capacity, or …

I’m not an exercise physiologist, hoping that summary is correct.

[bbarrera]

@Jackc70

So in my specific cases, my last workouts have, according to Garmin, been harder than they are prescribed as being (despite my HR being neither too high or too low) and I can assume then that this is down to fatigue so I should take some recovery time?

ok, going back to your first post:

@Jackc70

I’ve noticed that my last few VO2 Max sessions have shown as being Anaerobic on Garmin when in fact I haven’t gone anywhere near my Anaerobic zone for either Power or HR. I’ve double checked all my zones are correct and they are.

I dunno, and even with full access to your training data it might be an outlier, or require a coach’s mind to give a good answer.

FWIW the EPOC paper has a table outlining possible reasons for EPOC being higher or lower than usual:

I’ll give you a concrete example from my weekly 2-hour zone2 ride:

The first and third rows were very hot days. Therefore I reduced power and rode on RPE, with one eye on HR just to make sure it was bouncing around in usual 130-139bpm range.

That first row was Tuesday, 3 days ago, and second workout after 9 days off the bike for illness related mid-season break.

Monday’s workout was in 102F heat, and 21-minutes of tempo that Garmin correctly identified as tempo and gave it an aerobic score of 3.6 (3.0 to 3.9 is Impacting).

Tuesday’s 100TSS it was mid 90s and I was feeling Monday’s high temps and the 9 days off the bike. Even with a 65 TSS you can see that Garmin rated it a respectable 3.2. Going back to that table of possible causes for elevated EPOC, the second row has high temps/elevation/humidy, and the recommended action is “decrease absolute work rate to match previous EPOC levels.” Which is what I did intuitively, but after a workout like that its nice to see a score that reflects some progress toward workout’s goal.

[Jackc70]

Thank you, just acknowledging your excellent posts. Will absorb this and rreflect on it and come back to you.