Drag factor (again)

[bogus]

Morning folks,

I got my Model D in early December and I must say I'm absolutely loving it to the point where I can hardly walk past it without jumping aboard.

Regarding drag factor, I've read a dozen explanations and certainly understand what's going on with the mechanics of the machine when adjusting it's value with the flywheel dial, but I've never found any attempt to link this variable with other metrics in the rowing stroke. Most explanations are summarised with "it doesn't matter", or "use a value between 3 and 5", or "use what gives you the best time/distance".

So I'll ask a hopefully straightforward question...

If a rower rows 10km at a certain stroke rate (say 23 s/m) and expends a certain amount of energy (say 630 calories) with his machine set to a drag factor of 110, and then the next day the same rower at the same body weight on the same rowing machine rows the same distance (10km) at the same stroke rate (23 s/m) and expends the same amount of energy (630 calories) at a drag factor of 130, how will the two finishing times compare?

Now that I've written the question down like that I'm thinking the answer should be obvious, but I'll still welcome someone rubbing my nose in it.


Happy Valentine's day.

[Citroen]

Feed the numbers into https://www.concept2.com/indoor-rowers/ ... calculator and you'll see it's identical no matter which way you slice it.

BTW, nobody on here uses calories as a measure of their workout.
Everyone uses time, distance, stroke rate and pace.

[jamesg]

The erg's PM measures the power we deliver to the handle and converts this power to speed using a cube law: W=kV³.

For the same power, V is the same.

Power is force x speed. Since we're all different, we may be suited to work best at different combinations of force and speed. The erg lets us choose our preferred combination, by controlling, via the drag factor, the speed of the flywheel at the catch.

However we are not all that different, despite some being 7 foot tall and others 5, weight in proportion or worse. So most use 130 and couldn't really care less. Effectively, the human impedance curve seems to be almost flat; we have some choice as to how to work. Necessarily, being the product of evolution.

I use 85 - 90 drag via a special trick. Even at so low drag and with no strength at all, I can still produce > 200W, if I want to (so not often), but not for long. I work most days for 30 minutes at 110-130W, rate 20, and it seems to keep me fit. Which is the sole scope of the erg.

[Ombrax]

Most explanations are summarized with "it doesn't matter", or "use a value between 3 and 5", or "use what gives you the best time/distance".

I'll add another one that I think is more appropriate: Pick whatever feels best to you for the type of rowing you happen to doing.

Don't over-think this. In my case it's almost always 120. If I were a huge 250 lb weightlifter who was only interested in getting the shortest possible time in a 500m spriny it would probably be higher. If I were a little kid it would probably be less.

However, if you want to be highly scientific about how you go about doing this, then set up an experiment where you test multiple pace, distance and DF combinations (essentially a 3-d matrix of conditions) and collect as much data as you like. Personally I think there are too many variables to do this properly, but if it interests you then it could be worth a try.

[Dangerscouse]

Drag is all too often seen as a silver bullet that can magically unlock a massive amount of performance, but in reality it's just not that important.

I rowed for most of last year at about 115-120, but for the past few months I've used circa 132. I have set PBs using both drag factors, but I don't attribute any importance to it.

I can honestly say that you will find a drag that does just feel right, much like music taste; there is no right or wrong, within reason

[Big J]

I can't remember the exact drag factor I use, but I think it's around 170-180. It's 8 on the damper. I don't use anything lower than that now as it feels like I'm pulling against nothing.

[Nomath]

However, if you want to be highly scientific about how you go about doing this, then set up an experiment where you test multiple pace, distance and DF combinations (essentially a 3-d matrix of conditions) and collect as much data as you like. Personally I think there are too many variables to do this properly, but if it interests you then it could be worth a try.

Such an experiment under scientific control has been done, twice. I reported on it in a now-locked topic. If you read my opening post and especially study the graphs, you will see that several questions from the poster of the current topic can be answered.
I think the key figure in answering the question is the one below:



The C2 erg does not measure calories. It measures flywheel speed and from this it calculates power input. Power is converted into pace by a simple formula, so pace is another way to express power. Calories are also derived from power by an approximate formula.
What the figure shows is that for a group of 12 young club rowers, rowing at the same pace, the lower drag factor (i.e. 100) results in a higher heart rate than at the higher drag factor (i.c. 150). The difference is not big, but significant and consistent : 3-4 bpm

It you accept that the heart rate is the best monitor that we have for the strain on our cardiovascular system, the next figure is interesting. It shows the power per stroke as a function of relative heart rate (i.e. % of HRmax ; HRmax is the heart rate after a 3 min all-out effort).



At the same relative heart rate, the power in a stroke at the higher drag factor is considerably higher. One of the reasons is that the effective drive is longer (the handle picks the flywheel speed up earlier in the drive).

The data in the graphs are taken from the paper Effects of Stroke Resistance on Rowing Economy in Club Rowers Post-Season, by D.A. Kane and co-authors in Int. J. Sports Medicine, 2012

[Jayson rower]

I can’t seem to go any lower than 10setting, 3-5 setting there’s nothing there to pull, I feel like it’s 2 runners
Doing 2k run 1 going slightly up hill to the other slightly running downhill, what one would have had the hardest run with the most effort put in, yes the downhill might off been faster but the up hill runner would of felt the pain more and will be stronger for the next hill

But if you swapped them around after 6 wks of training to see them doing each other’s, run how would it work out!!

Does anybody else train on a 10setting?

J

[Dangerscouse]

Does anybody else train on a 10setting?

I used to years and years ago, but I haven't for many years. I know of two people that do, but that's probably all.

[Jayson rower]

Does anybody else train on a 10setting?

I used to years and years ago, but I haven't for many years. I know of two people that do, but that's probably all.

have you retired? Or just dropped the settings

[Cyclist2]

I'm sure long time forum readers will note that most drag factor questions are asked by fairly new erg-ers. Most everyone that has been doing this for a long time has figured out that DF really doesn't matter. Some days I feel like using 160, other days 110. Depends on what I want to "feel" in my workout; strength or higher rate technique. I can work up sweat at any DF and if, halfway through the workout, I don't like it, I change it. My long steady tempo rows are around 120-125 because that's what I am the most comfortable with and it is closest to the feel of my single shell.

[Citroen]

I can’t seem to go any lower than 10setting, 3-5 setting there’s nothing there to pull, I feel like it’s 2 runners

Is the machine clean?
What drag factor does the monitor show on damper 10?

[Tsnor]

So I'll ask a hopefully straightforward question...

If a rower rows 10km at a certain stroke rate (say 23 s/m) and expends a certain amount of energy (say 630 calories) with his machine set to a drag factor of 110, and then the next day the same rower at the same body weight on the same rowing machine rows the same distance (10km) at the same stroke rate (23 s/m) and expends the same amount of energy (630 calories) at a drag factor of 130, how will the two finishing times compare?

how will the two finishing times compare?

IDENTICAL TIMES.

The other discussion here is the value of different drag setting.

The PM5 computes the actual force every stroke by measuring how fast the blades slow. If you do the same work, the PM5 measure the same energy and the finish time is the same. Different drag settings give different starting and ending fan speed on each stroke, but same energy is measured. Higher drag factor = slower fan.

[Jayson rower]

I can’t seem to go any lower than 10setting, 3-5 setting there’s nothing there to pull, I feel like it’s 2 runners

Is the machine clean?
What drag factor does the monitor show on damper 10?

Hi Citroen

It was new last year, and it’s been maintained well
The drag factor is around 250

[Tsnor]

I can’t seem to go any lower than 10setting, 3-5 setting there’s nothing there to pull, I feel like it’s 2 runners

Is the machine clean?
What drag factor does the monitor show on damper 10?

Hi Citroen

It was new last year, and it’s been maintained well
The drag factor is around 250

LOL, I think I see the problem. Most people do not row with drag factor that high. It is not how a boat feels. If you usually row at 250 then the other settings will feel very light. The technique you use is likely not workable at the 115 to 120 drag I use. To get high wattage / low splits at 120 drag you need fast leg drive rather than a slow high-torque pull.

Google something like "BEST CONCEPT2 DRAG FACTOR" to get a million conflicting opinions. Here is Concept2's opinion https://www.concept2.com/indoor-rowers/ ... etting-101

Enjoy.