BikeErg "easier" that RowErg

[gvcormac]

Here's research confirming what I think is unsurprising: BikeErg ergs are easier to generate than RowErg.

https://www.researchgate.net/publicatio ... ale_rowers

I informally reproduced the results by rowing 5000m @ 2:29 (103W) with a final HR of 135. On the bike, 10000m @ 2:29 (103W) with a final HR of 125.

The paper explains the result by the fact that the RowErg does not account for the energy required to move body back and forth. Presumably this would be less for slides or Dynamic, because you are moving the rower which weighs less than your torso, but they don't test this.

Presumably the BikeErg misses a bit of energy due to leg motion, but a lot less than the rower does due to body motion.

[ArmandoChavezUNC]

There's no such thing as "easier" or "harder" - they are two different exercises.

Of course cycling is going to elicit a lower HR than rowing - it's a seated exercise with only leg involvement. Rowing uses many more muscles. That doesn't make it any easier or harder. You can push to exhaustion on either one.

And a paper examining physiological response on "well trained rowers" on a C2 bike vs a C2 erg is..... weird. Rowers erg.

[gvcormac]

There's no such thing as "easier" or "harder" - they are two different exercises.

Of course cycling is going to elicit a lower HR than rowing - it's a seated exercise with only leg involvement. Rowing uses many more muscles. That doesn't make it any easier or harder. You can push to exhaustion on either one.

And a paper examining physiological response on "well trained rowers" on a C2 bike vs a C2 erg is..... weird. Rowers erg.

If the two exercises were producing the same power, HR would be comparable.

Yes, you're able to generate more maximum power on a rower, but that's not the question this paper addressess.

[JaapvanE]

I must say, you can't support the conclusion with the data, IMHO:

Despite both the RowErg and BikeErg coming from the same manufacturer and having identical resistance mechanisms, the present study shows that when normalised for PO [Power Output] the RowErg requires the rower to work significantly harder. These data strongly agree with previous literature and confirm the notion that theConcept II RowErg is likely to under-report PO during the recovery phase of the rowing stroke.

There are several possible reasons for this which aren't investigated at all. For example that cycling allows certain muscles to be used to generate power (hamstrings) that are big and strong, but can not strongly used during the drive. A more isolated movement automatically results in the remaining muscles having to work harder, making the excercise tougher.

As an aside, research at the University in Ulm, with a mechanical simulation, shows that there are some issues with power measurement at the Concept2. However, when rowers use proper technique, the PM5 data is quite acceptable: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8821892/

[JaapvanE]

If the two exercises were producing the same power, HR would be comparable.

There is this thing called human effectiveness, which also is a soft assumption under many VO2 Max appeoximations: one excercise is easier for the human body than another. Generating 100W with a pure leg-drive is easy for most rowers, generating a 100W with only a pure arm drive is nearly impossible for most rowers. The sheer size of the muscles involved affects the effectiveness of the human body and thus the resulting HR.

[gvcormac]

If the two exercises were producing the same power, HR would be comparable.

There is this thing called human effectiveness, which also is a soft assumption under many VO2 Max appeoximations: one excercise is easier for the human body than another. Generating 100W with a pure leg-drive is easy for most rowers, generating a 100W with only a pure arm drive is nearly impossible for most rowers. The sheer size of the muscles involved affects the effectiveness of the human body and thus the resulting HR.

I think we're still at cross purposes. The point of the study is not what device allows you to achieve V02 Max. For me, clearly that is the rower, and not the bike. For elite cyclists, that may be different.

The point is how much power is being measured compared to how much is being generated. The rower captures a smaller fraction than the bike.

[JaapvanE]

The point is how much power is being measured compared to how much is being generated. The rower captures a smaller fraction than the bike.

Yes, and if they used a machine where they could actually measure the energy put in, like the university of Ulm did, then they would have a point.

The power indicated on the PM5 is the power delivered to the flywheel (based on angular displacement of the flywheel) not the subject has put in to get the flywheel moving. So the effectiveness of getting the flywheel moving, by definition, is not included in such measurement.

They use average heartrate to support the assumption that the more power is generated by the test subjects (and thus the PM5 is wrong). And to me, that is an extremely weak approach as HR is subject to many variables which aren't excluded in any way. Rowing uses different musclegroups, many of them smaller and thus less easy capable of generating 100W. Also, at the catch, part of the body is compressed, making breathing less easy and movements more elaborate, typically raising HR. Cycling is quite an efficient way of transferring energy, especially when there is no real physical movement of the bike. So transfer efficiency between a bike and rower are quite different.

So, the only thing they might be able to conclude (although with N = 10 and too little info about background is given) is that generating the same indicated power on two different machines has different physical effects on the subjects. Whether one of the two PM5's is to blame (and than which?) or that the rowing excercise is just tougher they can't conclude based on the data.

[gvcormac]

The point is how much power is being measured compared to how much is being generated. The rower captures a smaller fraction than the bike.

Yes, and if they used a machine where they could actually measure the energy put in, like the university of Ulm did, then they would have a point.

If i'm readings the paper correctly, the Ulm authors did a simulation in which a mechanical device applied power, whereas the Turner/Rice study used oxygen consumption. I don't see either of these as inherently more accurate.

The former measures only work applied to the flywheel. The latter measures total metabolic energy.

It takes more metabolic energy on the rower than on the bike to achieve the same power to the flywheel, as measured by the PM. The Ulm study does not contradict this observation. Moreover, it shows that the power to the flywheel measured by the PM is accurate to within a couple of percent, so that could not explain the difference. The difference can be explained by the overall efficiency of delivering muscle effort to the flywheel, which is lower for the rower. The primary reason for this is likely wasted body motion.

HR is an approximation to oxygen consumption which I used in my informal experiment. Turner/Rice actually measured oxygen consumption.

[JaapvanE]

It takes more metabolic energy on the rower than on the bike to achieve the same power to the flywheel, as measured by the PM. The Ulm study does not contradict this observation. Moreover, it shows that the power to the flywheel measured by the PM is accurate to within a couple of percent, so that could not explain the difference. The difference can be explained by the overall efficiency of delivering muscle effort to the flywheel, which is lower for the rower. The primary reason for this is likely wasted body motion.

I agree with you on that one, but when I read the conclusion of the article, it reads

confirm the notion that theConcept II RowErg is likely to under-report PO during the recovery phase of the rowing stroke.

Which is not true, as the PM5 accounts for the power measured on the flywheel and thus, by definition, does not measure any power during recovery. So it is not underreporting, it measures something else than the authors assume it measures.

[jamesg]

I'd suggest the intermittency of Rowerg power delivery has a large effect.

At race ratings we work for about 1/3 of the time: so the peak power is three times the average. Add to this that the power curve is roughly a half sine wave, the instantantaneous max power will be at least 4 times the average. Since peak power depends on applied force, which can be limited by both speed of action and strength, the maximum force that we can apply will also represent a limit to applied power.

Also of course, the force developed by the legs to reach the handle must go through other muscle groups, which must contract. This transit will not be free of charge.

[gvcormac]

I'd suggest the intermittency of Rowerg power delivery has a large effect.

At race ratings we work for about 1/3 of the time: so the peak power is three times the average. Add to this that the power curve is roughly a half sine wave, the instantantaneous max power will be at least 4 times the average. Since peak power depends on applied force, which can be limited by both speed of action and strength, the maximum force that we can apply will also represent a limit to applied power.

Also of course, the force developed by the legs to reach the handle must go through other muscle groups, which must contract. This transit will not be free of charge.

Sure, but we're talking here about average aerobic power over an extended period. Of course that can be exceeded for short intervals. The RowErg is good at measuring the average. It measures precisely the amount of energy dissipated during recovery, which, on average, must be equal to the amount gained during the power stroke. Some of the power stroke energy goes into the flywheel, so it is measured precisely. The rest goes into overcoming air resistance which can be estimated using the air resistance during recovery. As the Ulm paper notes, there may be some mismatch between the shapes of the velocity curves for stroke and recovery (particularly with artificially improper strokes) so this estimate can be off a bit. But not much.

I think you're being too hard on the other paper. They simply make the point that the erg doesn't measure all of the physical work done by the person rowing. That's true, and moving the body back and forth is a large part of where that physical energy is expended. No doubt some work is done by the bikeerg rider in moving legs back and forth as well, but that's lower mass and shorter distance.

[ArmandoChavezUNC]

If the two exercises were producing the same power, HR would be comparable.

This is simply not true. If you grab a person at random and ask them to produce a given wattage on the erg and the bike, their HRs will almost assuredly not be equal.

For starters, focusing on HR is a bit foolish because it is easily affected by many factors unrelated to intensity. But beyond that, there are so many other factors that influence how easily someone can produce wattage on one machine vs the other, including, but not limited to: mass, upper body strength, leg strength, experience/fitness rowing vs cycling, technique, etc.

[gvcormac]

If the two exercises were producing the same power, HR would be comparable.

This is simply not true. If you grab a person at random and ask them to produce a given wattage on the erg and the bike, their HRs will almost assuredly not be equal.

For starters, focusing on HR is a bit foolish because it is easily affected by many factors unrelated to intensity. But beyond that, there are so many other factors that influence how easily someone can produce wattage on one machine vs the other, including, but not limited to: mass, upper body strength, leg strength, experience/fitness rowing vs cycling, technique, etc.

There is not a great deal of variation in heart rate for an individual under aerobic conditions for a given amount of power. Sure it's an approximation, which is why the paper actually measured O2 consumption, and why I said "comparable" not identical. It is also why I gave my HR after 30 minutes of continuous activity, not after a sprint.

And although my subject line said "easier" what I was really talking about was not perceived easiness, but how much physical work you need to do to get a given power reading. That is higher for the rower than for the bike. If you need to do less work to get the same reading,that's "easier" in a sense.

As I have mentioned in a previous post, I don't have the leg stamina to achieve max HR on the bike, but I can do it easily on the rower (or running). That isn't because the rower is "easier" in the sense that I am using the term. But for a power level that I am able to achieve, I will burn more calories on the rower than on the bike.

[Carl Watts]

I'd suggest the intermittency of Rowerg power delivery has a large effect.

At race ratings we work for about 1/3 of the time: so the peak power is three times the average. Add to this that the power curve is roughly a half sine wave, the instantantaneous max power will be at least 4 times the average. Since peak power depends on applied force, which can be limited by both speed of action and strength, the maximum force that we can apply will also represent a limit to applied power.

Also of course, the force developed by the legs to reach the handle must go through other muscle groups, which must contract. This transit will not be free of charge.

Probably the best and most accurate post here, except perhaps for the word instantaneous.

This subject has been covered over and over and most people simply don't get it. Others simply cannot get it that energy is lost in simply moving your entire body up and down the slide and that is before you even get into the very short duration you have to get power into the flywheel.

Put simply, there is a reason that concept 2 will HALVE your bike meters in a challenge to that of the Erg and a WR will not stand on a Dynamic rower it needs to be done on a static .The Dynamic would need its own separate set of WR because they cannot be directly compared to the static rower.

[gvcormac]

Put simply, there is a reason that concept 2 will HALVE your bike meters in a challenge to that of the Erg and a WR will not stand on a Dynamic rower it needs to be done on a static .The Dynamic would need its own separate set of WR because they cannot be directly compared to the static rower.

Half is only a ballpark correction. C2 calculates watts from pace/500m on the rower and pace/1000m on the bike. So watts or 1000m times on the bike represent less metabolic energy expendature than watts of 500m times on the rower.