Rower is too hard to row

[JaapvanE]

I appreciate your comments. You are thinking but you are throwing out odd ball options. No one is watching me at either place. No bungee cords? No seat friction. No fans installed that point at the flywheel.

When you row, you perform work. There is a large part of that that a PM5 can actually measure (i.e. the power delivered to the flywheel). There is a portion of the work that it can't measure as it is lost before the flywheel (i.e. chain stifness, bungee stifness, seat friction, etc.). So when machines feel different, it typically is because of these factors.

Could the drag factor be messed up? In other words, it says 130 but it is really 180. Possible but if I pull it really hard, it should be showing a speed in the 1:30's per 500 pace, not the slow pace I get.

A PM5 recalculates the drag for each stroke. If you connect ErgData to it, you can see what it calculates per stroke. Unless the sensor has some obscure defect, it should do its job perfectly.

It might be that one of the PM5's is set to the wrong rower type (a PM5 has an option to set it to a specific type of RowErg). You could check that via the menu.

[stevegaspars]

I thought this was mentioned but it must have been a different thread. Have you checked that the PM5 is set to the correct machine type?

Edit: Sorry, didn't see the thread page 2 until i refreshed. Beaten.

[nick rockliff]

I appreciate your comments. You are thinking but you are throwing out odd ball options. No one is watching me at either place. No bungee cords? No seat friction. No fans installed that point at the flywheel.

Could the drag factor be messed up? In other words, it says 130 but it is really 180. Possible but if I pull it really hard, it should be showing a speed in the 1:30's per 500 pace, not the slow pace I get.

How would I check/fix chain or bearing stiffness?

I still don't understand the conversation about Newtons. I understand physics but not how that helps.

Take the fan cover off, remove the fly wheel. Then just pull the handle, it should be very free moving.

Mechanically, the C2 is very simple and there is very little that can go wrong to make a difference between two machines.

[Nomath]

...
Any other ideas?

Going by the numbers you presented in the opening post :

• Ergometer-A 7:45 for 2000 m means 223 W average

• Ergometer-B 7:50 for 2000 m means 216 W average

Note that this is the power over the entire stroke, which means that the average power in the drive is much higher. E.g. for 1.5 sec drive/1.0 sec recovery (24 spm) the power difference in the drive increases to 11W.

Could the difference be caused by a tenser bungee cord? Yes, quite possible!

I measured the bungee tension of my own C2 with a luggage scale: it varied from 1.2 kg near the catch position to 2.2 kg near the finish position. Note that 1.0 kg on the luggage scale display equals 10N.
Take average 1.7 kg = 17 N. Take stroke rate 24 spm = 2.5 sec/stroke. Take roughly 1.5 sec drive ; 1.5 m drive distance.
Power needed for extending the bunjee in the drive = 17 x 1.5/1.5 = 17W.
It is hard to find real measurements for bungee tensions on this forum, but a difference of 1 kg between a heavily-used erg and a fairly-new erg seems quite possible. It would account for 10W difference.

Some people say "the bungee is elastic, so the energy used for extending it is returned in the recovery".
What the bungee does in the recovery is that it helps you to accelerate the body towards the catch position, but all the kinetic energy must be absorbed by your muscles nearing the catch position. There is probably no gain from a tenser bungee in the recovery!

[Ombrax]

• Ergometer-A 7:45 for 2000 m means 223 W average

• Ergometer-B 7:50 for 2000 m means 216 W average

Some quick calculation:

216 / 223 = 96.86%. In other words, essentially a 3.1% difference between the two.

That doesn't strike me as a huge difference.

[Slidewinder]

Could the difference be caused by a tenser bungee cord? Yes, quite possible!

Thankyou Nomath. A very similar post to what I had already drafted and was going to post tomorrow.

I used JaapvanE's suggested 20N as a possible difference between bungee cord strength on the two machines. I did however find a video in which the owner of an old and new C2 rower checked the bungee strength of both with a digital scale. The old machine showed 1.4 kg at the start of the pull, increasing to 2.2kg at the end of the pull. The new machine went from 1.8 kg at the start to 5.1 kg at the end of the pull. So both your estimate and his are in accord with reality, maybe even a bit low.

I also, like you, do not accept the argument that the strength of the elastic cord is unimportant because the cord returns its stored energy to the user on the recovery. The reasoning goes that although a stronger cord makes it harder on the drive it makes it easier on the recovery, so everything balances out. I add to your refutation: I don't accept the elastic-cord-strength-makes-no-difference argument because I know, as does everyone here, that pulling on a strong elastic cord tires you more quickly than pulling on a weak one. The C2 elastic cord does not have magical properties that changes this reality.

Ombrax comments that the OP's reported time difference between the two machines is very small, perhaps suggesting that it is insignificant. Five seconds is a long time in the closing moments of a race, and five seconds very definitely separates the winner from the loser. In an on-line race with a bungee cord strength difference of 1 to 3 kg between machines, the PMs could be showing in the time/distance display the actual winner as the loser, and the actual loser as the winner. Further, since a weaker bungee cord is an advantage, there is the possibility of tampering to create this advantage. All this is not good.

[Ombrax]

Five seconds is a long time in the closing moments of a race, and five seconds very definitely separates the winner from the loser. In an on-line race with a bungee cord strength difference of 1 to 3 kg between machines, the PMs could be showing in the time/distance display the actual winner as the loser, and the actual loser as the winner. Further, since a weaker bungee cord is an advantage, there is the possibility of tampering to create this advantage. All this is not good.

At least as far as "official" races go, I'm pretty sure everyone uses ergs of the same age. I haven't participated in any, and have only attended a handful, but I believe that to be the case.

[JaapvanE]

Five seconds is a long time in the closing moments of a race, and five seconds very definitely separates the winner from the loser. In an on-line race with a bungee cord strength difference of 1 to 3 kg between machines, the PMs could be showing in the time/distance display the actual winner as the loser, and the actual loser as the winner.

In OTW rowing there are races where specific lanes are in a serious disadvantage due to the wind. I come from skiracing, and being assigned a bib above twenty for most races is a guaranteed loss due to environmental conditions. In formula 1, you see the same for starting positions. Life isn't fair, and racing certainly isn't.

As long as machines are similar in age and maintenance, and are assigned randomly, it is fair enough. Even large events like Hyrox have a fleet of rowing machines.

Further, since a weaker bungee cord is an advantage, there is the possibility of tampering to create this advantage. All this is not good.

Why not cut it entirely when you are at it? There are very clear rules what contestans can and cannot do during a race. Touching their own machine is strongly limited, and touching someone else's is way out of line and will get you disqualified. As touching all things mechanical requires you to disconnect the rail and raise the plastic cover, you are seen.

[JaapvanE]

E.g. for 1.5 sec drive/1.0 sec recovery (24 spm) the power difference in the drive increases to 11W.

This is a horrible ratio. When this happends, something is really off with your technique. Even when it is reversed, it is doubtfull.

I measured the bungee tension of my own C2 with a luggage scale: it varied from 1.2 kg near the catch position to 2.2 kg near the finish position. Note that 1.0 kg on the luggage scale display equals 10N.
Take average 1.7 kg = 17 N. Take stroke rate 24 spm = 2.5 sec/stroke. Take roughly 1.5 sec drive ; 1.5 m drive distance.

First of all: a typical drive is twice as fast as that. It is around 0.6 to 0.8 seconds at 20-22SPM. Probably a bit faster at higher stroke rates.

Power needed for extending the bunjee in the drive = 17 x 1.5/1.5 = 17W.
It is hard to find real measurements for bungee tensions on this forum, but a difference of 1 kg between a heavily-used erg and a fairly-new erg seems quite possible. It would account for 10W difference.

So having a big lunch (increasing my body weight with 1 kg) will also cost me 5 seconds? Are you serious?

[Nomath]

....
Some quick calculation:

216 / 223 = 96.86%. In other words, essentially a 3.1% difference between the two.

That doesn't strike me as a huge difference.

I agree that 5 sec on 2K doesn't look like a huge difference. But put yourself in the position of the topic poster. He finds that he can row 5 sec faster, possibly a PR, on heavily used ergs in the gym, but not on his home machine that is in better condition. Wouldn't you be disappointed and look for an explanation?

If you want to contribute to this issue rather than talk out the difference, I urge you to take a luggage scale and measure the bungee tension on your own erg. In that way we get a pool of real numbers instead of debating on abstracts.

[Nomath]

...
So having a big lunch (increasing my body weight with 1 kg) will also cost me 5 seconds? Are you serious?

Instead of ridiculing my calculation, I suggest that you review your statements. We are debating the possible effect of bungee tension on power. I suggest that we also stick to the case of the topic poster : a 5 sec / 7W difference on 2K.

Regarding the time ratio drive:recovery, you should not be misled by what the Performance Monitor tells you about the drive time. The PM cannot see the initial aceleration after the catch. The PM only start to measure power input as the handle speed matches the speed of the flywheel. The same holds for the last part of the drive when the handle speed drops below the corresponding speed of the flywheel. Both time periods are part of the drive and correspondingly reduce the recovery time.

My assumption of a drive : recovery ratio of 1.5 : 1.0 is not unrealistic, especially for an all-out effort. Shorter recoveries are the main way to speed up if leg and arm force are limited. I am not talking about a calm "pull strong - rest in the recovery" stroke often advocated here by jamesg.

I remember several topics in which a topic poster complained that a fairly new rower feels hard compared to the typical gym rowers. The typical response on this forum is : look for the drag factors !
My thesis is that also the bungee tension has a significant effect on the time/power. I suggest that you measure the bungee tensions of your own rower and possibly the rowers on the gym. It's easy and quickly done with a luggage scale. If you report them here we build up a base of facts rather then vague perceptions.

[nick rockliff]

Bungee cord?


I’ll get my coat

Now look what you've done

[Sakly]

Bungee cord?


I’ll get my coat

Now look what you've done

[nick rockliff]

...
So having a big lunch (increasing my body weight with 1 kg) will also cost me 5 seconds? Are you serious?

Instead of ridiculing my calculation, I suggest that you review your statements. We are debating the possible effect of bungee tension on power. I suggest that we also stick to the case of the topic poster : a 5 sec / 7W difference on 2K.

Regarding the time ratio drive:recovery, you should not be misled by what the Performance Monitor tells you about the drive time. The PM cannot see the initial aceleration after the catch. The PM only start to measure power input as the handle speed matches the speed of the flywheel. The same holds for the last part of the drive when the handle speed drops below the corresponding speed of the flywheel. Both time periods are part of the drive and correspondingly reduce the recovery time.

My assumption of a drive : recovery ratio of 1.5 : 1.0 is not unrealistic, especially for an all-out effort. Shorter recoveries are the main way to speed up if leg and arm force are limited. I am not talking about a calm "pull strong - rest in the recovery" stroke often advocated here by jamesg.

I remember several topics in which a topic poster complained that a fairly new rower feels hard compared to the typical gym rowers. The typical response on this forum is : look for the drag factor!
My thesis is that also the bungee tension has a significant effect on the time/power. I suggest that you measure the bungee tensions of your own rower and possibly the rowers on the gym. It's easy and quickly done with a luggage scale. If you report them here we build up a base of facts rather then vague perceptions.

I have a 2005 D which had done around 60 million mtrs. Last year I changed the chain, axle, axle bearings, chain sprocket, chain guides and bungee.

There is no difference between before and after. Bungee makes no difference.

[Nomath]

...
There is no difference between before and after. Bungee makes no difference.

What was the bungee tension before the revision and what is it after the revision ?