Erg is a power meter and then what?

[jackarabit]

Been reading some old threads containing fascinating posts suggesting that the C2 performance monitor is the rowing training equivalent of the bike racing power meter. Du-uh! you say, everyone knows that. I do too, sort of. I get glimpses of a practical application in the watts calculator and its inverse, the split time calculator. At the moment, I'm rowing my way thru the C2UK weight loss programme. Invariably, I attempt to cap HR in prescribed zone but also watch watts and rate. Can't watch current split time without giving chase. I'm afraid that I'll trade the devil I know for another If I try to predict the wattage I should be churning in each HR band but can't avoid it! Below is a predictive chart of wattage I "should" be able to produce in the HR zones of the utilization training schema.

I took my average split time for best 2K to date, got the wattage equivalent from the wattage calculator (142). Multiplied 142 by the percentages maxHR determinant of boundaries of each HR zone. Table below of results. Seems to describe my current "performance" fairly well as my current 30' time is low UT1 or high AT time and my HM 5' splits indicate that I rowed consistently in the middle of the UT2 zone and I know I was under 100watt average the entire time. Obviously, I am a weak, unfit, slow, old man. I'm a lot more interested in hearing if there is methodological validity in using the standard HR zone boundaries expressed as percentages of MHR and applying them to maximal wattage as determined by a semi-aerobic short effort? Or am I quite simply full of it? Jack



Watts equivalent of 9:00.7 @ 2K = 142. 142 X standard HR zone boundary %s gives tabulation following:

PREDICTED WATTS AV. IN HR TARGET ZONES (Jack)

UT2: 78-100
UT1: 100-113
AT: 113-121
TR: 121-128


PREDICTED SPLIT TIMES (Jack)

UT2: 2:45-2:32
UT1: 2:32-2:29
AT: 2:29-2:23
TR: 2:23-2:20

[hjs]

Those hf one are way to low. Firdt find out what hf reserve is, max hf minus min. You can,t calculate that, but find out on the erg max, and min is the lowest you see in rest.

[jackarabit]

Not talking bpm. Talking watts and time. I know the quotidian answer to the quotidian question. My max HR is 154 and I routinely row at 156 b/m without undue aerobic stress or after effects. So maybe my ticker will go to 165 or 171? Is there any validity to my method of determining what I'm currently capable of in watts average? I want a pinup for the monitor that I can consult for inspiration. Stella Stevens in her bath would also do it! Man I am old!

[hjs]

Not talking bpm. Talking watts and time. I know the quotidian answer to the quotidian question. My max HR is 154 and I routinely row at 156 b/m without undue aerobic stress or after effects. So maybe my ticker will go to 165 or 171? Is there any validity to my method of determining what I'm currently capable of in watts average? I want a pinup for the monitor that I can consult for inspiration. Stella Stevens in her bath would also do it! Man I am old!

No there is not, the watt outcome follows your specific fitness and hf. You can not calculate them by definition.

Old beats the alternative

[jackarabit]

Guess I'm full of it. Wait, is this a correlation I see before me? Just finished 4X6'AT. Here's the numbers:

1. 114W. 23spm. 2:25.2 av. split
2. 116W. 21. 2:24.4
3. 111W. 21. 2:26.6
4. 119W. 22. 2:23.0

Trying to hold HR 135 to 139b/m but excursion into TR heart rate band averaging 142-144b/m in second and subsequent intervals. Let the horse have his head last iteration and saw 156b/m on the HR watch. Didn't feel like a Borgian sprint to the death to me and my heart rate dropped off just fine in 1 minute rest. Whatever the vagaries of HR, watts numbers for all four iterations fall in the 113-121 band predicted from my best 2K. Average split times for all four intervals also fall within the 2:29-2:23 which my funny math[s] predicted.

My resting HR is 54. My max HR could be 154 or 160 or 165 or 171. I've started going by perceived exertion. If it's hard work and doesn't kill me I get to do it again. Jack

[Edward4492]

I've spent a lot of time with bicycle power meters (for you cyclists Power Tap and Quark). The main difference between true power meters and the C2 is that there are strain gages in a power meter that actually measure the force you are applying to the pedals. As I understand it the C2 measures power, but it's a calculation based on pace. A 2:00m pace is (approximately) 200 watts. It doesn't matter how you develop that pace (high rate, soft pull, low rate hard pull). There are virtually no variables on the erg. A cyclist going uphill at 8 mph could be putting out 400w while doing zero watts at 30 mph on the downhill. First time users are usually a little distracted by the wide swings in power. A skilled TT'er can hold about a 20w swing at best on the bike, a skilled erg'er can dial at in with one or two watts swing. but the erg still measures wattage, it's a calculation of stroke rate, length of pull, and how fast the actual pull is.

I may go back to it, but I got totally away from HR training when i was bike racing. i worked strictly on power. I'm currently doing the same thing on the C2 and have been focusing on watts/stroke. My goal has been to be able to carry a 9.5 - 10 w/s as I rate up. As I said , may add HR back into the equation.

Not sayin' my way is the right way; but it's where I'm at right now.

[lindsayh]

Not sayin' my way is the right way; but it's where I'm at right now.

I suspect there is no one "right way". The great appeal of the erg is that everything is so measurable but you don't have to take a lot of notice if you don't want to. I don't really understand any of it very well especially when we get into watts. Just hop on the machine, work hard and have some fun works for me.

[jackarabit]

Great explanation Edward, of the difference between calculation from deceleration in a flywheel and measurement by strain gauge in a crankset! I'm trying to work on long stroke, low rate, and consistent effort stroke to stroke. If I can only carry my Liliputian 4 or 5 watts/stroke up to higher rates, I'll be satisfied. Satisfied to get there. Maybe not satisfied to stop there if the body is willing? Jack

[gregsmith01748]

As I understand it the C2 measures power, but it's a calculation based on pace.

It's actually the other way around. The C2 measures the acceleration and deceleration of the flywheel. The rotational inertia of the flywheel is accurately known and the deceleration is used to determine the drag. In turn that allows the acceleration to be turned into the force and therefore power.

The concept of pace on the erg is artificial. The power is measured directly and the pace is calculated based on what a similar rower would achieve in a "straight four" on the water.

[Edward4492]

That sounds like the correct explanation (as compared to my wild ass guess at how it works).

[jackarabit]

Interesting that the designers of a sim rowing algorithm would assign each of us a quarter interest in a boat without a brain. I would have guessed single scull. Then there's that business about the adjustable shutter or damper which is supposed to produce the feel of the long "run" of a needle-like shell (was it an eight?) at some particular df and the pry it thru the water feel of a beamy rowboat at another. Inventive minds to be sure and it would be interesting to see how much was invented after the patent was granted! Obviously the spoke and vane first model did not have such a level of either functional or legendary sophistication. Jack

[coastline]

Here is a link with information on the development of the C2 power monitor:

http://www.ieeeghn.org/wiki/index.php/O ... lix_Kocher

[jackarabit]

Not a great deal there about the Dreissegackers but a little bit about the Kellermans' monitor design and their failure to seek patent protection. Jack

[Citroen]

As I understand it the C2 measures power, but it's a calculation based on pace. A 2:00m pace is (approximately) 200 watts.

BBBZZZZZTTT - wrong!

The C2 uses a tacho to count revolutions of a flywheel with a known mass. From those tacho pulses which gives it a rotational velocity it calculates the number of watts being input into the system and the damping on the stroke recovery.

ALL other numbers such as pace & calories are derived from the watts.

Details here: http://www.atm.ox.ac.uk/rowing/physics/ergometer.html

[c2jonw]

Here is a link with information on the development of the C2 power monitor:

http://www.ieeeghn.org/wiki/index.php/O ... lix_Kocher

Well that's one side of the story. Reminds me of the Winston Churchill quote "history will be kind to me for I intend to write it". C2JonW