Optimal drag factor

[Cyclingman1]

There is just a whole lot of conflicting, confusing info concerning drag factor in this forum.

It almost seems as though many, even those seemingly quite knowledgeable, are saying that it does not matter. Or do whatever feels good. That is way too vague. A large range of damper settings can feel okay. I'm not speaking of damper settings to simulate water feel, but specifically to minimize indoor C2 time for a given distance. I can see the damper setting being different for different distances.

Even though rowing and cycling are different, with cycling, optimal gearing is not really all that indeterminate. Sure anyone can pick a gear that is easy to spin for given terrain, but that is not optimal. Let's say for a moderate hill, there probably is a gear that is optimal for traversing the hill in the least time. In other words, what is the highest gear one can use and still keep a maintainable, fairly brisk RPM. And it is pretty easy to figure that out too. As one gets fitter, the gear can increase. With a racing bike there are 20 distinct settings - not as variable as with a C2. RE: different distances. Gearing choice is affected by distance. Energy must be conserved the greater the distance, hence a lower gear.

I can't believe that rowing is not the same. It would seem that one should be trying to pick the highest drag factor that one can pull at a maintainable, brisk SPM. I wonder if there is a tried and true method of determing what the optimal drag factor should be for a particular person with particular fitness for say a 2000m best time row. Something beyond whatever feels good.

[Citroen]

You're making a mistake of comparing drag factor to cycle gearing.

The idea for drag factor is to make your ergo require the same amount of effort as your boat. The drag co-efficient of a 1X is different from a 4 different from a 4+ and very different from an 8.

The middle of the range should be much like a 4+.

So for the on the water rowers their drag may be dictated by a combination of two things 1) boat and 2) coach.

For the indoor only rowers, the combination of drag and stroke rate is likely predicated by four things 1) gender 2) weight 3) height and 4) personal preference.

The monitor doesn't know where the lever is set, it only sees the tacho signal from the flywheel magnets and does a bunch of maths because the mass of the flywheel is know it can calculate the damping effect on the recovery of the stroke. A couple of externals affect damping 1) altitude (not relevant to those of us in the flatlands) and 2) amount of crud and fluff in the fan.

[Cyclingman1]

The way that drag factor gets discussed and described, it would seem that for maximum speed, that is, least drag, everyone would set the damper to the very minimum.

[Bob S.]

The way that drag factor gets discussed and described, it would seem that for maximum speed, that is, least drag, everyone would set the damper to the very minimum.

The speed, i.e. the inverse of the pace shown on the monitor, is determined by the effort put into the wheel, not by any real speed. In particular, it does not represent the speed of the wheel. A very fast spin of the wheel at low drag does not take much effort and will not show a low pace.

Bob S.

[Cyclingman1]

It would seem that one should be trying to pick the highest drag factor that one can pull at a maintainable, brisk SPM. I wonder if there is a tried and true method of determing what the optimal drag factor should be for a particular person with particular fitness for say a 2000m best time row.

A very fast spin of the wheel at low drag does not take much effort and will not show a low pace.

So the converse is true? A fast spin at a high drag takes more effort and will show a quicker time per 500m? In other words the highest drag factor until one cannot maintain a steady SPM?

[Tinus]

Does cycling have well defined optimal gears? (ie. if you know someone's power and body dimensions it is possible to get the optimal gear and cadence frequency?)

The problem with rowing is that there are too many variables to be able to state any general rules. Beginning with a general rule of thumb and using experiment (do whatever works best) to get to a more precise gear, is the best way to get to the optimal gear.

There are, by the way, some calculators which give very precise answers to the optimal gear in rowing on an erg. It uses the optimal handle velocity as determined from observations of rowing on water. The funny thing is that these optimal handle velocities (as determined by observation) are not the same for each boat type. There are several reasons why handle velocities are not the same for different boat types. In the same way it is true for erging.

This makes finding the optimal gear on an erg more complicated. People who are used to different boat types are addapted to different handle speeds. It is very difficult to predict what is best on the erg. The same handle speeds as one is used to do in the boat is very likely not the answer as well (It is logical that someone who is used to row in a single should not try to mimic the handle speed in an eight, why would it not be the same case for the rower in the single changing to an erg?).

[Cyclingman1]

Definitely am not suggesting that one pre-calculate gearing for a bike or an erg. I am speaking of determining the setting based on experience on the fly. For biking it really is straightforward. Pedal and keep increasing the gear (and effort) to the point where maximum speed is reached while RPMs are at a reasonable, maintainable pace. It may require a couple of ups and downs on gear selection.

So how about rowing? One would think that a a second person could gradually increase the damper setting while more and more effort is made producing faster time per 500m until the point of non-sustainability is reached. May require a couple of sessions. Please explain how this is a flawed theory?

[jamesg]

set the damper to the very minimum

That's a good way to do it; but it will feel very slack at the catch, and difficult to catch up with the flywheel. All we need then do is increase it gradually so we still have a smooth quick catch with no slam, but not too much loss of length.

Another advantage is that it's easy to learn to row, with fast full length strokes.

[Bob S.]

So how about rowing? One would think that a a second person could gradually increase the damper setting while more and more effort is made producing faster time per 500m until the point of non-sustainability is reached. May require a couple of sessions. Please explain how this is a flawed theory?

It might work, but only couple of sessions is very optimistic. There are other variables to take into account. Stroke rate is one. The most effective damper setting at one stroke rate is not necessarily the most effective at another. Duration of a piece is another. Achieving a very low pace for a short period doesn't mean that it can be sustained for a long row. You mention a point of non-sustainability, but that is just sort of a point of minimum possible pace (or maximum possible speed). A pace that could be sustained for just 500m would be too hard to sustain for 5km and I really doubt that they would both have the same optimum drag factor.

So there are three major factors involved and all three are continuously variable within fairly broad ranges, especially the duration which can be a low as a few strokes in a low pull attempt or a super marathon like a recent some 40hr+ effort. Actually the reasonable range of 500m to the FM is broad enough to make the point.

Another, but particularly difficult, factor to consider is the effect of changing DF and/or stroke rate on technique and the deterioration of technique as fatigue builds up.

I, for one, would be happy to be able to systematically optimize all these factors, but I am not the least optimistic that it can be done without an enormous investment of time.

Bob S.

[Cyclingman1]

You all may notice that I did not in my suggestion mention acutal SPM or distance, etc. But I can fill that in. I am speaking of doing this test close to the race speed (x.x/500m) for 2000m. I would probably be talking about SPM of say 32-34 ( or choose your own). Of course in the test a person can slow down and come back up to speed when a new damper setting is made. I'm sure more than one session would be needed, but not many more.

I would think that optimization is exactly what anyone would want to do, who is serious about rowing best times. I relate best to cycling and running, where every racer I know very carefully optimizes pacing, gearing, etc. But I just have not seen a lot of talk about that here in these forums. There seems to be this rule-of-thumb talk about drag factor. The typical racer uses such and so drag factor. I just refuse to go with some general number like, say, 135 drag factor. That has no relevance to me.

As I said in an earlier post, I do believe that drag factor would vary some according to distance. But if one has a known point to start from at a given distance, like 2K then finding a new drag factor is going to be a whole lot easier.

[Carl Watts]

Even if you look at what the Elite rowers use as a drag factor, it will serve as a guide but that is all.

Dont quote me but I have been told that the likes of Rob Waddel use a DF of about 110. I personally find that this is to low for me as I clearly just don't have the leg speed to get this to work. At best unless your at an Elite level for a period of time it would change anyway. Mine went from 164 to 136 over the course of 2 years and I would say if your in the 110 to 130 range (for anything other than short sprints) with great times and pace then your potentially rowing at close enough to your optimal drag. Probably a bit frustrating from a cyclist point of view where you can find a specific gear to work with, but it just doesn't work that way on the Erg.

One thing I would add however is don't go blaming the "wrong" DF for a really poor performance, you need to look elsewhere.

[Cyclingman1]

When a rower goes from 164 to 136 drag factor what aspect of the rowing changes to maintain if not increase speed (time/500m)? It is almost conterintuitive. Doesn't anyone go from 136 to 164 drag factor to improve performance?

[hjs]

When a rower goes from 164 to 136 drag factor what aspect of the rowing changes to maintain if not increase speed (time/500m)? It is almost conterintuitive. Doesn't anyone go from 136 to 164 drag factor to improve performance?

The higher the drag the more time you have for your stroke, at higher drag you can be a bit more sloppy, for rowing otw quick legs and precise stroking is more important. And the faster the boat is you are in, the more important and the lower drag you should use on the erg.

More 160 drag would be pulling a house, I row 110 ish the most comfortable.

[Dickie]

When a rower goes from 164 to 136 drag factor what aspect of the rowing changes to maintain if not increase speed (time/500m)? It is almost conterintuitive. Doesn't anyone go from 136 to 164 drag factor to improve performance?

The higher the drag the more time you have for your stroke, at higher drag you can be a bit more sloppy, for rowing otw quick legs and precise stroking is more important. And the faster the boat is you are in, the more important and the lower drag you should use on the erg.

More 160 drag would be pulling a house, I row 110 ish the most comfortable.

power on the stroke is determined by Force times Distance all over time. So assume 30 strokes per minute, that is one stroke every 2 seconds. Assume also that the rower will pull the same length stroke at high or low drag factor. You can get the same result using High and Low drag factors by varying the time used for the pull versus the time used for recovery.

For example, Applying 60Kg of force on a stroke that is half drive and half recovery is

(60*4)/1 =240

and applying 40 Kg of force on a stroke that is 1/3 drive and 2/3 recovery is

(40*4)/.66666 = 240

In a 2 second stroke 1/2 and 1/2 is 1 second drive and 1 second recovery
In a 2 second stroke 1/3 and 2/3 is .6666 second drive and 1.3333 recovery

Also you have to think about the cube relationship the calculations use to figure pace and wattage on the monitor. i.e. a 1:30 Pace takes 8 times the energy as a 3:00 pace

This is definitely not like gearing on a bike

So you can use whatever drag is best for you, and there is no general optimum. Instead everyone has a different optimum. If you are an old weightlifter, then you probably feel more comfortable at higher drag because your muscles are strong and slow. If a cyclist then you are probably more comfortable at lower drag because your legs are not as strong as a weightlifter but are faster due to high cycling cadence.

it's been several decades since high school and college physics but in general this is correct and it is how things work on the erg.

Fred Dickie

[Carl Watts]

Yes you obviously have to factor in your SPM along with the Drag Factor. If you look at your Heartrate you will find that with the same drag and pace it is much harder to row at say 17spm than it is to row at 23 spm.

There is an optimum cadence on a bike correct ? from memory it is like 90 and Lance Armstrong was 100 so the gearing is simply chosen to get the cadence to match.

Yes you will have a differnent muscles coming from Cycling, where as I went from Cycling to weights so my most comfortable rowing is a higher drag but and lower rating. I never go over 30 spm unless its a 500M PB and 26spm is typical. Perhaps I'm rating to low but then again at 100Kg there is a significant amount of energy wasted just going up and down the slide that you don't have as a lightweight so as above above it's all about finding what works for you.