Does Garmin use Firstbeat calorie calc method when biking w/ a powermeter paired?

I did not read all the thread, and do not have any powermeter, so cannot test it myself, but did you do the test with or without a Garmin's HRM chest strap? If done without an external HRM strap, then it would be comprehensible that Garmin prioritizes the powermeter over Firstbeat, since the HRV measurement by the internal OHRM is not really reliable when moving. Data based on the powermeter would be quite possibly more accurate.

With Garmin HRM 3-SS. Always. On F3HR and F5+. The calories in kcal was always equal to work in kJ, so practically Garmin decided to use the inverse of the conversion ratio between cal and joule for the mechanical efficiency. I mean 1/4.184=23.9%.

Since I always use a strap with ANT+, the logics you kindly pointed to can be excluded.

For our mutual understanding, now I checked a cycling activity logged with my Edge 530. And although it is part of another product line, it calculates the same clumsy way as Fenixes meaning that in case of Edge 530 active calories are either the same as work, or there is a tiny difference.

Example:

https://connect.garmin.com/modern/activity/10681513281 Both metrics are 1129 (1129 kcal and 1129 kJ).

Some difference exists only in those cases when the stopped time is really substantial (huge), I guess in this case sometimes there may be short periods when the connection with powermeter is lost, and it may result in some accumulating difference. You know when you walk away from your bicycle to have a pee or something like that.

And just read what HermanB from Firtstbeat wrote:

”According to one of the physiologists, who had a look at his own personal data, it does seem that, when paired with a power meter, the device is outputting energy expenditure from the power meter data. It's an interesting discovery, and not something that I was aware of earlier.”

So he confirmed my findings, see his post made in this thread 6 years ago: forums.garmin.com/.../790188  

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With Garmin HRM 3-SS

Olala, it still exists? Are you sure it supports HRV? I cannot even find any official specs for it on Garmin's website. 

Yep. I am fully sure.

As I remember HRM-2 equipped by a newer premium soft strap also supported HRV. But it is not fully sure, I may be wrong.

I never had newer HRM than HRM 3-SS (three pieces allocated within the family), for a long while I used it with Garmin premium straps then from this autumn with a Polar strap sold with and without H10 HRM.

I used a Firstbeat sw (trial version) to check my HRV data (R-R data, more precisely), a plugin within Sporttracks 3.0 etc. I do remember that there was a secret menu already on my 910XT to enable or disable the recording of hrv data into the .fit file. And you know what? When 910XT was launched in 2011 maybe there was no HRM 3-SS yet. But definitely no HRM4 Run/Swim/Tri, no Pro, no Dual etc.

But going back to the original question. Are you not shocked about it? I mean Garmin had started a bad practice before acquiring Firstbeat and even Firstbeat people was surprised about it. Then after Garmin bought and integrated Firstbeat nothing has changed regarding this practice. And by today who cares except for 1 or 2 human beings.

EDIT: enjoy it fellrnr.com/.../Heart_Rate_Variability

Well, the only way to get the message to the developers, is submitting a request at Share Ideas | Garmin, or signing for the beta program, and reporting it as a "bug" at the next beta firmware version release. However a new firmware for Fenix 3 is highly unlikely, so you would have to test it with a more recent device.

We are in F5 forum. I did have F3, now I have F6X and Enduro..

When I formally reported it both via Submit an idea and outdoors support email address I got no feedback. When I reported it to Firstbeat 6 years ago I got a promise from a Finnish executive that they made a try at Garmin. I was told they had contacted the relevant Garmin dept/team, and it was the last piece of info.

It is easier to say for Garmin that it was a deliberate decision, a “designed this way” solution. Like in case of course and tracklog coloring change (Enduro 1), which for me seems to be a bug and not a new approach.

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As I remember HRM-2 equipped by a newer premium soft strap also supported HRV.

It does. Even the very oldskool HRM-1 (before the soft strap design) supports it, and all HRM chest straps that support the ANT+ Device Profile "Heart rate monitor" do; the only requirement is that they report the intervals between heartbeats in milliseconds.

As an aside, the basics haven't changed for years, for example the Suunto T6 (2004) was rudimentary by today's standards. but also recorded the intervals between heartbeats in milliseconds from an ANT chest strap, just as today, It didn't have a lot of memory and processing power, all the analysis was done afterwards in software for PC (Suunto Training Manager), using FirstBeat algorithms. From just the heartbeat interval data it calculated: Heart rate, EPOC, Training effect, Ventilation volume, Respiratory rate, Oxygen consumption (VO2), Energy consumption. HRV was a factor they used, but it was not reported separately (I think).

For me, after moving to Garmin, the Training Effect and VO2Max scores remained the same, because they were calculated in the same way. Strangely, Garmin didn't include respiration rate until much later.

Firstbeat still sells analysis software for (mostly) teams and professional athletes.

Thanks for the confirmation and the history. Using your link I was able to remember what the exact name of Firstbeat software was. I used the free trial of Firstbeat Athlete, so a very similar name as today. And I found some description about it. http://ns.suunto.com/pdf/Firstbeat_ATHLETE_datasheet.pdf

It also came to my mind that how much  I as a 910XT owner was impressed by the concept of EPOC when I first saw it in this F Athlete sw. 

Btw one of the Garmin trashbin examples , or more elegantly said, one of the “How to confuse a cat?” examples, is that Edge series use EPOC, while wearables use LOAD for the very same concept. When I recorded a ride both with my Edge 530 and F6X, these two metrics showed the very same value. And at least GC uses the same name for them.

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How to confuse a cat?” examples, is that Edge series use EPOC, while wearables use LOAD for the very same concept.

:-) Thoroughly confusing indeed! Thanks for the Firstbeat Athlete link. The screenshots remind me of Suunto Training Manager, amazing that you got that at no extra cost (on a CD) with a Suunto (not that these were cheap). If I had the time.. I would be tempted to see if I could still run STM and import data from FIT files.