Stretched Shock Cord & Time

[hjs]

You can exclude me from the "any of us" in your post. All major competitions are raced on brand spanking new machines, fresh out of the factory, and I'll wager that the shock cord tension is damn near identical for every machine.

If two competitors are within a second of each other over, maybe it has something to with the machine. Otherwise, it has a lot more to do with the person sitting on it, than the shock cord sitting inside it.

and that simply is the way it is................

[Slidewinder]

gregsmith,
As I pointed out, even if the variation in shock cord tension between new machines is acceptably small, this condition does not last. hjs observed that it is common for machines in gyms to have the shock cords so out of adjustment that the machines don't function properly. This is very poor advertising for Concept 2, and surely an incentive for C2 to investigate other chain return strategies.

The ideal chain return mechanism would be one that never needs adjustment, retaining a constant return force for the life of the machine. This would mean no elastics or springs in that mechanism. Is this possible? I can think of a couple of methods. It will never happen though if everyone continues to pretend that this is not a problem.

[Citroen]

and surely an incentive for C2 to investigate other chain return strategies.

Two ideas spring to mind from that: KISS and if it ain't broke don't fix it.

Gyms that don't maintain machines are simply advertising that they're crappy gyms not that the expensive kit in their gym is crappy. Maintenance so that machines are safe to use is one of the things I expect my membership fee to be spent on, if that doesn't happen I'll vote with my feet and go and spend my money at a gym where it does happen.

[hjs]

gregsmith,
As I pointed out, even if the variation in shock cord tension between new machines is acceptably small, this condition does not last. hjs observed that it is common for machines in gyms to have the shock cords so out of adjustment that the machines don't function properly. This is very poor advertising for Concept 2, and surely an incentive for C2 to investigate other chain return strategies.

The ideal chain return mechanism would be one that never needs adjustment, retaining a constant return force for the life of the machine. This would mean no elastics or springs in that mechanism. Is this possible? I can think of a couple of methods. It will never happen though if everyone continues to pretend that this is not a problem.

Why are you making such a big point of this?

really nobody does such things and people who (claim) score top results on the erg and don't race or are not able to match those results during are not taking seriously.
The erg is really a simple machine, the shock cord is not something that does influence races. Do you really think that nobody would have noticed this in practise if this problem excisted? A loose shock cord for the x time is not an plus, try it in practice and youm will notice, the slow chain on the returm will actually make the machine slower.

Poor maintined machine?, yes there are lot's of gyms who have them, that also does not give an advantage. It again wil make the machine harder to work on and thus slower.

[c2jonw]

Of course it takes some energy to stretch the bungee. Years ago we ran some simple controlled tests to see if there was a difference in effort required with a loose vs tight bungee cord. Simple enough for anyone to do with an erg and a heart monitor- row steady state or consistant intervals with tight bungee and monitor your hr. Loosen bungee and repeat. Do this a number of times at different distances. This was back in the days of the Model B which had a wider range of shock cord tension between the catch and finish due to the cord stretch characteristics and configuration of the return mechanism. We did not find any significant HR differences within the normal range of bungee tension. We surmised that much of the energy that is being put into the cord on the drive is being returned to the rower on the recovery, and some energy is lost in warming the bungee cord up.
Models C, D & E have a softer bungee and different return mechanism configuration which result in a much reduced difference between the catch and finish tensions. The new Dynamic Erg has an even lighter return force.
I think a much more significant difference between machines is the condition of the chain. In similar HR tests a dry, rusty chain did take more effort (higher HR) than an oiled chain to achieve the same score.
I'd be interested in actual tests and test results anyone might try to quantify this question. C2JonW

[Carl Watts]

Thanks for the information.

Will replace my cord as it appears to be slowing down my sprint rows due to the slow chain recovery.

[Slidewinder]

hjs wrote, "Why are you making such a big point of this?"
Are you not an equal participant in this discussion? Your interest is demonstrated by that participation.

I stated earlier that I am in full agreement that a shock cord so loose that the chain returns sluggishly is not going to help one's time. This is not the issue.

There is a range of cord tension over which the machine will function properly. At the lower end of that range, as on a well-used machine (and I emphasize - with the chain still returning properly), the force required to stretch the cord will be less. Less force required means less energy expended to record the same distance. This cannot be disputed.

jonw states that in early tests, heart rate was not appreciably affected by elastic tension variations, but he acknowledged that no firm conclusion can be drawn from those results. Regardless, a chain return mechanism that requires no adjustment and maintains a constant return force over the life of the machine is the ideal situation. A means to accomplish this is certainly worthy of investigation.

[hjs]

hjs wrote, "Why are you making such a big point of this?"
Are you not an equal participant in this discussion? Your interest is demonstrated by that participation.

You must be a politician. There are coming words from your keyboard, but you never answer a question.

My interest in not the shockcord, it's your claim that erg (racing) results are not compareble due to the shockcord. I say you are wrong and the slight bit of difference they could give is also less then the variance that can be seen in most other sports. Something you also ignored.

Wind, tracklane, Drawn opponent, having teammates in the race etc etc..

[paul s]

I think this is much ado about nothing, particularly from Mr. Slidewinder. Perhaps he could get on Ranger's Training Tread, and the two could go on endlessly driveling at each other.

Paul S

[Slidewinder]

KISS and if it ain't broke don't fix it.

Written like a true C2 groupie. This of course in response to my description of the ideal chain return mechanism.
ie: no shock cord; a constant return force for the life of the machine; no tension adjustment ever required.

If this were a political discussion, you would be categorized as a reactionary - opposed to all change.

Why do you assume that such a mechanism would be more complex than the existing elastic cord system (KISS - keep it simple)? If it ain't broke don't fix it? No, the elastic cord system isn't broke, but it has problems - needs periodic adjustment; pull force varies between used machines; eventual replacement of cord required.

Why is it impossible for you to acknowledge that it would be an improvement to have a chain return system that never requires adjustment or replacement?

You, and several others here, probably view yourselves as highly discerning in all things related to indoor rowing, but it's apparent that you have accepted the group-think mythology that the C2 machine, unlike all other machines ever built, is perfect, and no improvement is possible. I wasn't aware when I purchased my Model D that a prerequisite to being a member of the C2 club is to check one's critical faculties at the door.

I have a keen interest in the C2 machine, not because it's perfect. but because I recognize it's unrealized potential. There are many ways it could be improved. It could be something great, rather than merely good.

[hjs]

KISS and if it ain't broke don't fix it.

Written like a true C2 groupie. This of course in response to my description of the ideal chain return mechanism.
ie: no shock cord; a constant return force for the life of the machine; no tension adjustment ever required.

If this were a political discussion, you would be categorized as a reactionary - opposed to all change.

Why do you assume that such a mechanism would be more complex than the existing elastic cord system (KISS - keep it simple)? If it ain't broke don't fix it? No, the elastic cord system isn't broke, but it has problems - needs periodic adjustment; pull force varies between used machines; eventual replacement of cord required.

Why is it impossible for you to acknowledge that it would be an improvement to have a chain return system that never requires adjustment or replacement?

You, and several others here, probably view yourselves as highly discerning in all things related to indoor rowing, but it's apparent that you have accepted the group-think mythology that the C2 machine, unlike all other machines ever built, is perfect, and no improvement is possible. I wasn't aware when I purchased my Model D that a prerequisite to being a member of the C2 club is to check one's critical faculties at the door.

I have a keen interest in the C2 machine, not because it's perfect. but because I recognize it's unrealized potential. There are many ways it could be improved. It could be something great, rather than merely good.

Try the rowperfect, that is a much better machine. I am not kidding, it really is.

[JRBJR]

Try the rowperfect, that is a much better machine. I am not kidding, it really is.

Which Rowpefect are you referring to? The original model that makes as much noise as an Oldsmobile with a bad clutch, the new Australian RP3 which is only available to the Australian market, or the Belgian RP3 which costs over $3000 USD and has a flywheel assembly roller wobble problem that the Australian version does not?

[hjs]

Try the rowperfect, that is a much better machine. I am not kidding, it really is.

Which Rowpefect are you referring to? The original model that makes as much noise as an Oldsmobile with a bad clutch, the new Australian RP3 which is only available to the Australian market, or the Belgian RP3 which costs over $3000 USD and has a flywheel assembly roller wobble problem that the Australian version does not?

http://en.wikipedia.org/wiki/RowPerfect this one

I am not talking about price or noise for training itself does element are not important.

[Carl Watts]

Has anyone read this on the RowPerfect vs the Concept 2 compared to OTW ?

http://www.biorow.com/Papers_files/2005 ... eshnev.pdf

I thought it was quite interesting.

[Slidewinder]

Carl Watts,
Thanks for the link. It is interesting.

I say you are wrong that erg racing results are not comparable due to the shock cord.

It is basic physics that variations in shock cord tension between machines will affect times. Less tension (but not to the point of sluggish chain return), means less effort, means lower times.

At the risk of sounding like a broken record: Consider two machines, one of which requires one pound more force to stretch the elastic cord than the other. After one hundred strokes the user of this machine will have equivalently lifted a hundred pound weight through a distance - an effort not required by the user of the other machine. No deep understanding of Newtonian mechanics is needed to comprehend that this is going to affect times.

Some posters have presented the absurd argument that the more effort required to stretch the cord (ie: a higher tensioned cord) will actually result in reduced times. Even if we accept this nonsense, it is still an acknowledgement by those who believe this, that cord tension variations between machines affect recorded times.

Other posters have argued that none of this is a concern because only new machines with identical cord tensions are used in indoor rowing competitions. Maybe so, but many race participants train on used machines which have reduced shock cord tension. Consequently, they are recording incorrect training times. This is poor preparation for a competition.