Concept2 Forum

The 2K split to projected VO2max calculator is no longer shown on the C2 website. I don't know when it went away.

Wayback machine gave me a working copy after some clicking:
https://web.archive.org/web/20231002182 ... calculator

Anybody else use this ? (not a training aid, but fun if it gives you a good number)

They revamped the whole website, so it might take some time for it to reappear.

I used it next to other formula's for VO2Max, and it is pretty consistent with the results.

I also use it from time to time, so today as well when I stumbled across this thread
Highly trained gave me ~70, the other option ~54. I think the truth is in the middle. My Polar watch and belt give me 61, when doing the 'fitness test' (5min lying down and let the tech stuff do it's thing...).

Sakly wrote: ↑

June 19th, 2024, 11:22 am

I also use it from time to time, so today as well when I stumbled across this thread
Highly trained gave me ~70, the other option ~54. I think the truth is in the middle. My Polar watch and belt give me 61, when doing the 'fitness test' (5min lying down and let the tech stuff do it's thing...).

Sascha if you aren't "Highly trained" as one of 2 options, most of us never will be!

iain wrote: ↑

June 20th, 2024, 5:06 am

Sakly wrote: ↑

June 19th, 2024, 11:22 am

I also use it from time to time, so today as well when I stumbled across this thread
Highly trained gave me ~70, the other option ~54. I think the truth is in the middle. My Polar watch and belt give me 61, when doing the 'fitness test' (5min lying down and let the tech stuff do it's thing...).

Sascha if you aren't "Highly trained" as one of 2 options, most of us never will be!

I looked up the FAQ regarding this option and it tells:

If you have been rowing regularly for several years, training at least four days per week, doing a variety of workout types and improving your rowing scores, then we suggest selecting "Highly trained" when using the calculator.

Probably 'highly trained' is about right for me
Thx for your words of affirmation

It's still on the UK website:

https://www.concept2.co.uk/indoor-rower ... calculator

(Gives me 41, for the 60-69 age group "excellent". I'll take it!)

Rowan McSheen wrote: ↑

June 20th, 2024, 12:04 pm

It's still on the UK website:

https://www.concept2.co.uk/indoor-rower ... calculator

(Gives me 41, for the 60-69 age group "excellent". I'll take it!)

Mine says 42 or 46, depending on whether I claim to be trained or not. Running Cooper 12 minute test gives me more like 40 (based on 12 minutes from longer runs). These all seem to be OK for my age, also 60-69.

All of these formulas need to be taken with a grain of salt. Especially the smartwatch ones. At least these ones are somewhat objectively derived from a few precisely measurable quantities (except for "trained or not" which is a huge confound).

Cooper's book, Aerobics, got me into running in 1968.

Here are a bunch of calculators. The ones I tried (resting HR, 1.5 mile run, 2K rowing) are pretty consistent.

https://www.omnicalculator.com/sports/v ... calculator

gvcormac wrote: ↑

June 20th, 2024, 12:24 pm

All of these formulas need to be taken with a grain of salt.

I completely agree with this one in an abolute sense. So these formulas produce numbers which might relate to the actual VO2Max, or not. So your number from a formula might not be comparible to my number.

In a personal relative sense I found most formula's to be interesting: an improvement of VO2Max for me actually means something improved.

Especially the smartwatch ones. At least these ones are somewhat objectively derived from a few precisely measurable quantities (except for "trained or not" which is a huge confound).

Companies like FirstBeat (the guys making the algorithms for Garmin and many others) have a huge scientific base underpinning their algorithms. In all honesty, especially as it is Garmin's/FirstBeats core product (and only Concept2's aside analysis) with a huge scientific base and daily use by many high end athletes, I'd put more trust in these approximations.

My experience is that my VO2Max from my Garmin is extremely stable at 45, where as the Concept2 algorithm fluctuates a lot around 28-40. Bad/inefficient rowing technique might be a cause here, but one would expect some stability nonetheless.

JaapvanE wrote: ↑

June 20th, 2024, 12:43 pm

..
Companies like FirstBeat (the guys making the algorithms for Garmin and many others) have a huge scientific base underpinning their algorithms. In all honesty, especially as it is Garmin's/FirstBeats core product (and only Concept2's aside analysis) with a huge scientific base and daily use by many high end athletes, I'd put more trust in these approximations.

My experience is that my VO2Max from my Garmin is extremely stable at 45, where as the Concept2 algorithm fluctuates a lot around 28-40. Bad/inefficient rowing technique might be a cause here, but one would expect some stability nonetheless.

My Garmin 265 watch is no good for vo2max. I don't run and I don't use a power meter on my bike so the watch extrapolates V02max from WALKING. Even the firstbeat/garmin doc says the reported vo2max from walking is garbage, and that it is not used to adjust training guidance. Garmin will *not* use user reported cycling power number (e.g. from a fixed watt trainer like some lifecycles) to compute vo2max. So it's nice to have the C2 vo2max numbers. The two different C2 numbers come from different regressions of data, someone assigned all data points to a "highly trained" or not bucket then fitted a formula. I view the two numbers as two data points and mostly ignore which is highly trained since conceptually I'd expect a highly trained person to deliver a better (lower) split at the same vo2max, and the calculator says the opposite...

Tsnor wrote: ↑

June 20th, 2024, 3:13 pm

My Garmin 265 watch is no good for vo2max. I don't run and I don't use a power meter on my bike so the watch extrapolates V02max from WALKING. Even the firstbeat/garmin doc says the reported vo2max from walking is garbage, and that it is not used to adjust training guidance.

Hence my point about not being absolute approximations. Aside from the labtest, most VO2Max approximations use Max HR. In essence they use linear regression to extrapolate the power at MaxHR. And everybody here knows that for most, MaxHR is a wild guess to begin with. So it is doubtfull these numbers are accurate. But they are quite repeatable so using them in a relative sense (is my physical condition improving) is pretty OK.

C2's approach is a bit different, and thus interesting. Especially as it omits MaxHR as a factor. But it uses a 2K pace where rowing stroke quality has a huge impact, and where HR is omitted. If the limiting factor isn't the cardiovascular system (but muscle strength or form for example), the measurement isn't accurate either. But again, it is an nice indication something is improving when the number goes up.

Tsnor wrote: ↑

June 20th, 2024, 3:13 pm

Garmin will *not* use user reported cycling power number (e.g. from a fixed watt trainer like some lifecycles) to compute vo2max.

The issue is that you need quite some set of measurements before the traditional algorithms can do their trick. In technical terms, they do a sub-maximum step-test. In essence, they plot power vs heartrate, use that to do linear regression and extrapolate to the expected power at MaxHR. Use a specific formula per sport to tranform power into a O2 need (which assumes a certain efficiency), correct for weight and that is your VO2Max. As linear regression needs quite some datapoints and spread in these datapoints to become reliable, a single manual value won't work, nor will a static load as you can't extrapolate that to more power.

There are some more complex algorithms reaching maturity, which look for the amount of cardiac drift in steady state under constant workload, which might influence VO2Max (a factor currently called fatigue resistance) but it isn't commonly accepted yet.

Tsnor wrote: ↑

June 20th, 2024, 3:13 pm

So it's nice to have the C2 vo2max numbers. The two different C2 numbers come from different regressions of data, someone assigned all data points to a "highly trained" or not bucket then fitted a formula. I view the two numbers as two data points and mostly ignore which is highly trained since conceptually I'd expect a highly trained person to deliver a better (lower) split at the same vo2max, and the calculator says the opposite...

It is only partially unexpected. You'd expect a highly trained person to have lower splits to begin with AND have a high VO2Max. So it might only 'work' in a specific range. A decent analysis tool would indicate the calibrated VO2Max ranges and the GoodnessOfFit as well.

I think this is the effect of a cluster-analysis, where you see stronger correlations after clustering, but underlying causes aren't thoroughly analysed and thus you can get weird effects. For example, form might be a factor, but it is hard to out a number on it. But, it strongly corrolates with being highly trained or not, which can be expressed in a number. So in a cluster analysis you'll find the cluster, but as you're stacking correlations, effects are just weird sometimes.

My problem with the smartwatch calculations is that they don't make you do any sort of standardized stress test. They just cobble together a bunch of readings that may or may not be your best effort with a bunch of self-reported demographics that may or may not be correct.

I particularly like the Cooper test because it self-corrects for everything except sex. But it is not perfect because it depends on running ability.

The rowing test corrects for sex and also this intangible "training" component.

Built my own.

gvcormac wrote: ↑

June 20th, 2024, 9:05 pm

The rowing test corrects for sex and also this intangible "training" component.

But it ignores many other important factors, like quality of the stroke and wether your best 2K is actually your maximum effort (which in a sense is the same question wether your MaxHR really is your true maximum heart rate if you were really pushed to the absolute limit).

I structurally compare both on OpenRowingMonitor, and we now activate C2's algorithm only when HR has been at 90% of stated MaxHR for over a minute. On those sessions both approaches line up pretty well. But as soon as you leave that area, they deviate a lot.

To truly test VO2Max in a lab used to be an absolute disaster. When I was an athlete, we only took the test once every two years and the schedule after it was essentially cleared for the two weeks after for a recovery. Because that was what "going to the max" also implies. And that goes the same for the Cooper test. For most enthousiasts the current approach (extrapolation of a sub-max effort) suffices for most practical applications as comparing VO2Max across athletes is useless anyway, and you want to measure progress.

As an aside: please note that a VO2Max is actually sport dependent as both posture and muscles used can differ. So your running, cyclung and rowing can result in different VO2Max's.

"So your running, cycling and rowing can result in different VO2Max's"

Indeed. A running calc gave me 33. I don't treat any of this seriously: if it's a flattering number I'll take it thank you very much, if not then I won't!

The only way to obtain the true figure is to get yourself strapped up to various bits of electronic trickery in a lab. Which as a recreational paddler and plodder I'm never going to do. The calculators are just for fun.