Let's go Dynamic
Zbigniew A.
of Oslo, Norway.) Big thanks to C2 team and Norwegian distributor of C2
machines. Anyone wants to drop in for a test drive?
It took me some time to put it together, especially that i haven't seen
the assembled machine up close. Assembly manual is straightforward, fool
proof.
I was surprised how big the packages were, two HUGE cardboard boxes, one
of them really long. But after assembly the machine is neat: only 195
cm long -- and i am not sitting at the very end of it, so i am saving
over half a meter of room space. <like>
One is sitting considerably higher over the floor. Easier to get up
after a hard workout. :-)
PM4 display, normal.
They included Garmin HRM1G heart rate belt in a set. Bulky, bigger than
the old SUUNTO belt they used to give with PM4.
I skip the snapshots right now. How it looks you can see on C2 website.
==========================
How it feels to row on it?
*Very* similar to C2 on slides (or in my case on my DIY set of wheels).
One can feel that there is less mass moving, that's for one.
Now i regret that before the assembly i did not check the weight of a
foot carriage unit. It was surprisingly heavy in relation to it's size,
but it is certainly much less than a weight of a modern singlesculler.
I was hoping that the machine would run quieter, but it isn't. Maybe
that's because one is sitting right over the flywheel?
The fan is blowing on a rower, however only on one side, left arm and
left leg. I am yet to figure out if the draft on a left kidney is a good
or bad thing. <unsure>
PM4 display is at the arm length when sitting with legs straight. Very
easy to push the buttons cause ones body is almost not moving in
relation to the display. Display can be set at the face level or even
higher. <3 x like>
Now, when i started to row, it felt considerably different. However, it
took me some time to figure out what it is.
The "oar" handle is not pulling back! Well, just a tiny bit so the cord
-- yes, the cord, no chain here -- so the synthetic cord does not get
jammed during recovery. But you sit with the handle and after finishing
the stroke you just hold it "in the air". <love it!>
So, after a first session of easy rowing i can mention first two
differences, compared to C2 on slides: less mass moving and no pulling
back the oar handle.
What is considering the rowing dynamics, it is way too early to say.
Only after the 9th of January i will take it to the club, line up three
C2 machines side by side: C2 fixed head, C2 on slides and C2 Dynamic.
And then i will compare them directly.
Until then i can share only my first impressions.
--
Yours Virtually, Zibi
Andrew B
We have one of these at our club. The subjective feel is of more
resistance in the handle and less at the footstretcher than in a
standard C2 erg. I don't know if that reflects the actual mechanics of
the thing. You can, perhaps need to, row at a higher rate on the
dynamic. I can't currently match my best splits for any extended
period of time, probably because I've got the muscle memory for the
stationary. That in turn makes me wonder about the effectiveness of
training on the stationary erg, given that the mechanics are so
different from a boat. If moving from the stationary erg to the
dynamic exhibits underpreparedness for the latter, how much more is
that the case moving to the boat at the end of winter?
Kit
>
> - Show quoted text -
This blog post from Pete Dreissigacker http://www.concept2.com/us/company/blog/default.asp?id=677444685
states that the new dynamic C2 was based on experiments done by C2 in
the 1980s to simulate sliding riggers. So I guess you shouldnt expect
the new erg to feel much like either a stationary erg or for that
matter a normal boat.
Gman
> This blog post from Pete Dreissigackerhttp://www.concept2.com/us/company/blog/default.asp?id=677444685
> states that the new dynamic C2 was based on experiments done by C2 in
> the 1980s to simulate sliding riggers. So I guess you shouldnt expect
> the new erg to feel much like either a stationary erg or for that
> matter a normal boat.
The floating head rowing machine compared to a sliding rigger boat
movement is quite different.
Read this by Cas Rekers comparing a sliding rigger boat to a floating
head rowing machine (RP) http://www.rowperfect3.com/articles/CasSlidingRigger.pdf
he says to simulate a sliding rigger boat (on a land based RP) you
would "Have to increase the weight of the seat to around 11 kgs and
decrease the weight of the stretcher / flywheel to aroun 6.5 kgs."
Ergo the two are not the same.
Pete may have designed his C2 to resemble a sliding rigger (but I
can't see the point as we don't row in them).
Justus J.
> ... I can't currently match my best splits for any extended
> period of time, probably because I've got the muscle memory for the
> stationary. That in turn makes me wonder about the effectiveness of
> training on the stationary erg, given that the mechanics are so
> different from a boat. If moving from the stationary erg to the
> dynamic exhibits underpreparedness for the latter, how much more is
> that the case moving to the boat at the end of winter?
Good question. It might (or most probably will) require a little change
in technique. Training cardio is one thing, preparing for the racing
season is something different.
Justus
Kit
> > This blog post from Pete Dreissigackerhttp://www.concept2.com/us/company/blog/default.asp?id=677444685
> > states that the new dynamic C2 was based on experiments done by C2 in
> > the 1980s to simulate sliding riggers. So I guess you shouldnt expect
> > the new erg to feel much like either a stationary erg or for that
> > matter a normal boat.
>
> The floating head rowing machine compared to a sliding rigger boat
> movement is quite different.
>
> Read this by Cas Rekers comparing a sliding rigger boat to a floating
> he says to simulate a sliding rigger boat (on a land based RP) you
> would "Have to increase the weight of the seat to around 11 kgs and
> decrease the weight of the stretcher / flywheel to aroun 6.5 kgs."
> Ergo the two are not the same.
>
> Pete may have designed his C2 to resemble a sliding rigger (but I
> can't see the point as we don't row in them).
Me neither. And I don't think you can call the new C2 erg a "floating
head" one anyway. The "head" (ie the flywheel) stays stationary. What
moves is the foot carriage, which I assume weighs roughly the same as
a sliding rigger. So as you say, what's the point, unless you can add
weights to it. Say, 14kgs roughly.
Tinus
> So as you say, what's the point, unless you can add
> weights to it. Say, 14kgs roughly.
http://www.patentstorm.us/patents/5382210.html
The original design may have been made to resemble sliding riggers but
I don't believe it is still this same motivation for using the design.
Also, adding weight to something is much more easy than subtracting
it. The point would be versatility.
Charles Carroll
I have never gotten this "problem" about weight.
If a new or redesigned erg more closely simulates sculling, why worry about weight?
Haven't many of us been introduced to sculling in heavier boats - Restricted Singles, gigs, Aeros, Mass 24s, even wherries?
So what is the problem with learning to scull in a heavier boat? If a boat is good for learning the basics of sculling, why worry about it?
An similarly, why can't the same question be asked about ergs?
Cordially,
Charles
Carl Douglas
Happy New Year, Charles!
Weight (strictly speaking, mass) of each part which should move is a
determining factor in whether a simulator does well or badly at
simulating a particular form of sculling or rowing.
That's because rowing is a reciprocating action with several moving
masses & work is done, every stroke, to accelerate & decelerate each of
those masses.
In a fixed erg, much work is done in accelerating the body mass at the
catch & up the slide. And a lot of work is done in first accelerating
the body mass back towards front-stops, & a whole lot more to then bring
the body to a halt. If weights were strapped to your seat or shoulders,
they'd increase the masses to me pushed & pulled around, costing you
even more work in each stroke - or you'd have to drop your rate to
reduce those accelerations (by giving you more time to move along the
slide) & avoid that extra cost.
All this happens because the stretcher is immovable - i.e. is firmly
attached to the Earth's monstrous mass, so you could say it weighs what
the Earth weighs.
But your boat is very light. When you take a stroke your bodily CofG,
being that of a much larger mass than the boat, hardly accelerates or
decelerates, so very little energy goes into energy-sapping changes in
bodily velocity. Instead, & dependent on your technique & whether you
have your blades in the water or not, etc., the very light boat
accelerates & decelerates under you - to & fro about the mean speed of
you & your boat - which accelerations do not absorb much energy. So
more of your work is invested in sculling, in fact just the "right"
proportion of your total work, & the loadings & speeds of action are
correctly redistributed through the stroke cycle
Which illustrates the adverse effect of having the wrong masses in a
simulator. But you can look at it another way:
In drumming, is it as easy, quick & rhythmically worthwhile to play with
a heavy hammer in each hand, or to use drumsticks? And will using
hammers, not drumsticks, improve your skill & expression, or just make
you strong but clumsy & unmusical? I think we know the answers.
So if you row only a 20 ton barge, then you'll lack the technique for
the lively response that you get from uncontrolled foot pressure in a
racing single. And you'll have to unlearn some learned responses -
because the relative masses of barge & single are so very different.
Finally, ergs are used for very many hours as training aids. Unless you
particularly want to train various muscle sets under different loads &
at different speeds than in a single, why would you not care deeply
about dynamic similarity between boat & erg?
So it should be a prime concern in erg design to see that the body
members' speeds & loadings on the erg resemble, at all stages of the
stroke, those in sculling or rowing (whichever is your branch of our
sport). Which is why the masses moving in the erg do matter. It's not
everything, but it's very important to the quality of simulation.
Cheers -
Carl
--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: http://tinyurl.com/2tqujf
Email: ca...@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)
Zbigniew A.
> So what is the problem with learning to scull in a heavier boat? If a boat is good for learning the basics of sculling, why worry about it?
>
> An similarly, why can't the same question be asked about ergs?
And what if one is not only after learning the basics, if one wants to
develop his performance to the highest possible level?
--
Yours Virtually, Zibi
Charles Carroll
Now to get down to cases:
Who would disagree that having the wrong masses in a simulator would have an adverse effect on the simulation?
Or to use the example offered: I cannot think of any percussionist who would want to use a heavy hammer in place of drumsticks, and neither can I think of any sculler who would advocate training in a heavy barge in place of training in a fine boat.
So I would have to concede the point, that is, if the analogy were a heavy hammer is to a drumstick as a barge is to a fine boat.
But isn’t the analogy a bit different?
I was suggesting that a racing single is to a restricted single as C2’s new dynamic erg is to its erg on slides.
Carl, I readily concede that there is a difference.
What I am asking is what it the significance of this difference?
I have had about fifteen minutes four years ago on a RowPerfect when Sandy and I were in Staines visiting you. As for a C2 on slides, I have owned and used such a machine since Concept 2 began selling slides.
Of course my experience is limited, and I have never claimed to be a good sculler. In fact most mornings I am just happy to stay in the boat. But I must say I really cannot see a significant difference between the two machines.
Cordially,
Charles
Charles Carroll
> develop his performance to the highest possible level?
In that case I would train in the shell I intended to race.
Cordially,
Charles
Carl Douglas
I can't usefully comment on C2's new product as I haven't been near one
of the machines. As for the difference between a C2 static & a RP
dynamic, maybe 4 minutes is insufficient for you to relax & start
rowing, whereupon the difference is substantial. You could say that the
RP is to a shell as the C2 on slides is to a tub or heavy single, but
the C2 on slides is a far better simulator than the same without slides.
Only on a static erg do you need to control the slide on the recovery,
or pay a penalty in your knees & lower back at the catch. Only on a
fixed erg do you have first to get your body moving before you can think
of taking any sort of a catch that isn't an arms snatch. Only on a
fixed erg do you have to haul yourself off backstops.
If you want to learn how to catch with your bum & legs, then train on a
fixed erg. If you want to have a quick & well-loaded catch without
first driving the boat back, use for preference a RP for on that machine
you really can observe the same faults & feel the same responses as in a
boat. And I've used RP for exactly that purpose, with great benefit.
If those differences are not significant, we are not discussing teh same
sport ;)
Now take a squint at Magnus' excellent new thread. See how poorly the
fixed erg represents the on-water performance of lightweight scullers
(men & women)? You wouldn't get that kind of a result with such
repeatability were there no significant differences between boat &
machine. And the sample sizes are pretty decent too. I know Magnus
well & have come to respect greatly his diligence, his intellectual
rigour & the effort he invests into the studies reported on his website.
Put simply, the fixed erg is poor predictor of a rower's on-water
performance because it is a relatively poor rowing simulator - the
actions look the same as in the boat but the loads & speeds are not the
same.
We've known this for >30 years, but the seductive appeal of so-called
"measurable, unarguable erg data" can suck the brains out of coaches at
selection time. As a result, any number of heavy boat-stoppers get to
occupy seats which would better have been filled by weedy lighter types
who have some damned illicit trick of moving their single so much faster.
If it simulates well, a good erger will be an effective rower. If not,
there's your answer.
Good enough?
Zbigniew A.
Charles,
did i say "highest possible"? :-)
Rowing on a frozen water is not possible. And travelling to Portugal or
RSA for winter rowing camp is not possible. :-(
=========
My machine is in the club now, for a week of testing. Today, few veteran
rowers with a whole range of different backgrounds tried the new C2
Dynamic standing next to old "fixed head" C2s.
All have agreed to one thing: DYNAMIC IS MORE DIFFICULT! (than the old,
stationary C2.) They differ with theories on why it is difficult, and
with conclusions.
Couple of recreational rowers, for whom rowing is a way of weight
control or fighting a midlife blues, they were interested if new machine
makes easier to score good results? Hearing that it doesn't, they lost
interest. They prefer the old one. For them the new machine is just
"weird" or "difficult".
One very experienced rower, once national level, said about the catch
resembling the one on a real boat. He used a word "proper timing". He
said it requires careful coordination and makes technical flaws more
visible.
Another one, with a couple of medals from Worlds ang OGs, immediately
noticed that compressing the legs is more difficult and that his seat
travel is shorter on the dynamic. He thinks that it is important to have
a long reach and use the slides as much as possible. He says that the
old machine "teaches him" to use slides more, therefore he prefers the
old one. (He has one at home.)
Now, someone who's opinion i wanted to hear very much. Once upon a time
world champion on a coxless pair; they were considered "most technical
crew of the time". In late '80s FISA was distributing series of pictures
taken from still frames of their rowing as examples of "perfect
technique". :-)
He also thinks that the seat recovery, compressing the legs is kind of
difficult, requires effort. He said that on a real boat, when everything
goes well, recovery is effortless while here one has to "work on it" all
the time. He noticed less pull on a handle but wasn't sure if it is good.
When he is coaching, a lot of his instructions is about improving the
catch, it is really important to him. Now, when he was talking about the
catch on dynamic... you should see the grin on his face! :-)))))) He
says it gives him very "boat-like feeling".
That was more of the "first impressions".
--
Yours Virtually, Zibi
Zbigniew A.
Placed C2 Dynamic next to the old "fixed head" C2, side by side.
First i made a test of maximal power, 20" all out. Four times with
adequate rest in between; first static, then dynamic, static and dynamic
again.
Results were so clear that there was no need to do more than 4
repetitions. Trials 1 and 3 on fixed gave identical readings, trials 2
and 4 on dynamic very similar.
On Dynamic the power output was 7-8% higher and cadence also 8% higher.
Then i mounted C2 on the slides. I kept switching between these two
machines every minute, many times. Focusing only on a general "feel" and
technique.
First, one minute on a C2 on slides. Then, one minute on Dynamic. Then,
back to the traditional C2 on slides... And shock! How strong is the
pull of a handle!
/Now, you need some background information: I've been using C2 on slides
as my primary machine for more than a year -- outside of rowing on water
season that is. So it was nothing new to me. After i've got Dynamic two
weeks ago i was switching between the old, "fixed head" and dynamic many
times, but did not use C2 on slides in this period./
Only now, by trying Dynamic and the old C2 on slides side by side, i
realised how strong is the pull of the chain. I believe that normally,
when the old machine is standing firm on the ground this effect is kind
of "masked" by the inertia of rowers body. Only when C2 is rolling
freely on slides, this chain pull starts to be clearly visible.
So, after about 10 rounds of switching between the Dynamic and C2 on
slides my conclusion was that the *much* weaker pull on the handle of
Dynamic is the only difference. All the rest, especially the dynamics of
the stroke seem to be identical.
However, don't think this is the "only" difference. This is: OH MY GOD
what a difference it makes! Really. From the very first moments on
Dynamic i could feel that the pull on the handle is much less, but only
now, comparing these machines side by side with only a few seconds for a
change, i could realise what a difference it makes. When switching from
C2 on slides back to Dynamic it seems for a minute that one has to
"push" the handle, how big is the difference.
However, besides the enormous difference in the pull of the handle,
there was still some very subtle difference in the dynamics of recovery.
So, i brought a dumbbell from a weight room, 10 kg would fit nicely in
these "hooks" on top of the foot stretcher. After attaching the dumbbell
also the recovery of these two machines seems to be (almost) identical.
(Don't be picky, maybe 8 kg or maybe 12 kg would be better, i don't
know. I just took 10 kg because it was easy to fix it.)
The fact that the flywheel is moving in one and fixed in the other does
not matter, the linkage system in Dynamic takes care of this. The forces
during the stroke seem to be identical. Maybe Valery Kleshnev with his
computerised sensors could find some difference, but i couldn't.
So, the C2 on slides and C2 Dynamic seem to be very, very similar.
Perhaps there might be some slight difference in the friction of the
wheels -- Dynamic even with added weight felt kind of "more lively" --
but that is really a nuance. And of course Dynamic without a weight
feels "lighter", the same way like 14 kg single sculler feels lighter
than 28 kg sculler, even without a time trial. :-)
On that day i had a conversation with our club's London 2012 hopeful,
who said he can't match his interval times on the Dynamic with these on
normal C2. So two days later i made series of time trials on all three
machines. But i need some time to commit this into writing. Will try
tomorrow...
--
Yours Virtually, Zibi
donal...@gmail.com
concept D side by side with groups of 3 doing a series of 3 minute
pieces rate 26 quite hard on them. We dont have monitors on the RP but
what we are trying to do is use heart rate monitors and translate some
of the feel from the RP onto the concept.
Everyone was trying to maintain timing and on the finish this was
happening.
It seemed to me that the catch timing was out because on the RP you
take a shorter catch(ie cant compress as much and lock on quicker).
The concept you naturally over compress and probably pick the catch up
at pretty much the same point as on the RP once the slack is taken up.
We are trying to approach the catch on the concept in a more measured
way (ie not bouncing) but you still end up with slack so this doesnt
work totally satisfactorily....and your "split" suffers which I
suspect users will rebel against.
As someone who has done many many hours on ergs over the years and 3
years ago had a nasty injury which I put down to my technique on
concept 2(quadricep insertion into patella "went" which was very
painful and took a long long time to heal) . Also I had one lad have a
similar injury on the concept which may of course simply be
coincidental ( he hasnt done masses of erging). As a result I am
trying to get the kids to use the concept in a less aggressive way.
If we could swap tomorrow I would effect a swap but the reality is we
have 18 concepts at 3 schools and 2 with the club all with monitors
and used regularly. We have 2 row perfects(one mine) without monitors.
The concepts are very reliable and have good monitors and the RP's
look fragile cost a fortune and sound like a bag of old bones in
comparison. Kids that havnt been on ergs before dont like the wobbly
seat and floating head and those that are experienced have
reservations about these factors.
Relative cost, reliability concerns etc. all dictate against a switch
even when preaching to the converted.
It would be good if new RP could compete on price but undiscounted
price at £2000 for an RP with monitor against £1000 for a model d with
monitor the reality is that concept have the lower end of the market
tied up. RP really need an entry level competitor with monitor of
sufficient quality that is perceived by gyms first and foremost as
being viable if they are to take over the world.
The long term plan is to get 6 ergos into each of 22 schools once
current funding crisis is over though have a couple of significant
other items to put in place first. Id much rather go dynamic but at
the moment its not that likely.
Donal
Mike Barker
line ?
THere is some talk of a connecting rod - would this work, and how ?
Connection to the seat or to the footplate ? And how would the
simulated mass chage in these two cases ?
Zbigniew A.
My aim was to establish whether results of timed pieces made on three
different types of C2 ergs can be compared directly.
So i've put three machines side by side. After a long and thorough
warmup i made 12 x 500 m on fixed, dynamic and on slides, 4 rounds. I
tried to keep the same *subjective* level of intensity, about my 2k
pace. I tried not to look at the display readings, i would only look up
my HR, if anything. After each 500m trial there was 2 minutes AR and one
minute for a change -- start every 5 minutes. All results were stored on
a memory card and analyzed later at home.
All 12 trials returned *very* *similar* results: almost the same times
and the same heart rates, with one parameter varying consistently -- the
cadence.
My average cadence on fixed head was 30,5, on dynamic 27,5 and on slides
27,75.
Frankly, I find it counter intuitive and don't know what to make of it.
My coach has the complete spreadsheet with these results, maybe he will
find out. That was made a week ago and I moved on already.
--
Virtually Yours, Zibi
Zbigniew A.
I am sure that C2 will provide a solution pretty soon. I imagine it
would be some kind of lightweight "frame" of strength similar to modern
fishing rods. Perhaps symmetrical, going along on both sides.
And linking foot stretchers of course. Not the seats.
On a real boat seats are not connected either. The direct connection
between the rowers is through their foot stretchers.
--
Yours Virtually, Zibi
Carl Douglas
What Cas Rekers did when validating Rowperfect was to work with an
academic in Berlin (Justus may recall the name, I think it was something
like Schwann, but that could be quite wrong). They inserted a
dynamometer setup in the chain - i.e. a measuring device able to
generate an absolute measure & record of instantaneous force & speed
throughout the stroke.
With the data from this equipment, they compared input power with the
monitor record on the RP, and found this correlated very well throughout
the power range. They also measured power vs heart rate & rating, both
with the RP working in its normal dynamic (sliding head) mode & then
with the head movement locked (in which condition it had the same
non-dynamic characteristics as the fixed C-II machine). Again the
monitored & dynamometer readings correlated well.
However, a substantial & consistent difference in the delivered (i.e.
monitored) power was measured between the 2 modes with the subject
rowing at the same heart rate. There was a deficit in both monitored &
dynamometer computed power in the fixed head setup, amounting (from
memory) to ~130 watts. This deficit appeared to represent the extra
work required by the rower in simply accelerating & decelerating his
body, first up, & then down, the slide every stroke before actually
doing any work on the handle.
You may agree with me that none of that sounds counter-intuitive?
They also found that the monitor readings on a C-II machine (the model C
IIRC), which they also fitted with the same dynamometer arrangement,
were themselves less accurate. Not just that, but the power monitored
varied markedly according to the force profile employed.
This last - the variability - I attribute to the far from ideal intake
geometry of that machine (seen as a piece of turbomachinery) & the use
of a pleasantly quiet fan of a design which is bound, as most
well-designed fans are, to be peaky in its performance, whereas the
early C-II machines & the RP had fans which, by simply beating up the
air that passed through them) generated the required Drag = k V^2
relationship pretty well.
Anyone wanting to row faster (or to coach others to do so) must be ready
to create meaningful test scenarios & rigorously evaluate them. This is
not to hard to do, but if the conclusions depend to any extent on rower
perception then we risk getting them wrong. I'm not saying you got it
wrong, but you said your results were counter-intuitive. I feel that a
flaw in your test protocol was the lack of an absolute measure of
performance - which only a dynamometer could provide.
What do you think?
Charles Carroll
> Then, back to the traditional C2 on slides... And shock! How strong
> is the pull of a handle!
Zibi,
I am not clear on what you mean by the phrase "How stronge is the pull
of the handle."
On which erg is the pull of the handle stronger? The C2 on slides? Or
the new dynamic erg? Or the C2 fixed head erg?
And in which part of the stroke is the pull strong? During the drive?
Or during the recovery?
My a priori guess is that the new dynamic erg would have almost no
pull on the handle during the recovery. I just want to confirm this in
a real world test.
Also, do you feel any difference during the drive between the C2 on
slides and the new dynamic erg?
Again, a priori, I imagine that being able to adjust the Drag Factor
must act as a kind of equalizer between the two ergs.
People are always postulating that because a C2 on slides is roughly
40% heavier than a RowPerfect, the C2 on slides will "feel" as if you
are sculling in a tub whereas the RowPerfect will feel as if you are
sculling in a racing 1x. But, this has not been my experience.
Pity that you don't have a RowPerfect in your line up.
Cordially,
Charles
Charles Carroll
When Cas Rekers was validating the Rowperfect, did he compare it with
a C2 on slides?
I ask becuase my understanding is that Cas built the Rowperfect back
in 1988, and Concept2 did not start manufacturing slides until some
ten years later, around 1998 or 1999 I believe.
If Cas was comparing the Rowperfect to a static C2 - i.e. the fixed
C-II machine - then it seems to me the comparison is hardly
meaningful.
I have not used a static C2 in eleven years. In fact, whenever I climb
onto a static C2 I find that it is nearly impossible for me to use. It
just doesn't feel right.
Cordially,
Charles
Zbigniew A.
>> First, one minute on a C2 on slides. Then, one minute on Dynamic.
>> Then, back to the traditional C2 on slides... And shock! How strong
>> is the pull of a handle!
>
> Zibi,
>
> I am not clear on what you mean by the phrase "How stronge is the pull
> of the handle."
>
> On which erg is the pull of the handle stronger? The C2 on slides? Or
> the new dynamic erg? Or the C2 fixed head erg?
>
> And in which part of the stroke is the pull strong? During the drive?
> Or during the recovery?
Oh, excuse me for my half broken English! If something is not clear
blame it on my clumsy wording.
Of course the back pull is equally strong on stationary and on slides,
these machines are the same. But on slides it is somehow more visible.
I was using the old (well, model D) C2 alternatively on slides and
without (the latter as little as possible), for more than a year, and i
did not realize this until i compared them directly with the Dynamic.
And this strong pull is felt most clearly at the beginning of recovery.
The forces during the stroke are many times stronger so during the
stroke i could not feel the difference, not this kind of difference.
> My a priori guess is that the new dynamic erg would have almost no
> pull on the handle during the recovery. I just want to confirm this in
> a real world test.
Yes, you are absolutely right. Everybody who tried the new Dynamic could
feel that there is very little pull on a handle.
Again, i kept switching between fixed head C2 and Dynamic for about a
week, but it was always some time in between, sometimes they were in
different locations. Only when i had these machines side by side and
switched them with only a few seconds for a change, only then i could
realize the difference. And it was a shocking experience! The difference
in the pull is so big, that when rowing on Dynamic just after the old C2
it seems that one has to "push" the handle in order to begin the
recovery. Of course we can't push the handle. if we did the cord would
get jammed and it does not; but it feels so, at least for a moment.
> Also, do you feel any difference during the drive between the C2 on
> slides and the new dynamic erg?
No, not really.
Well... maybe... but *if* there is any difference in the drive, it must
be very subtle.
There is a tangible difference, though, between the Dynamic and C2 on
slides, in the feel during thre recovery. The Dynamic feels kind of
"more lively" and of course "the lack of the pull" is very nice. I use
quotation marks, cause there is a pull, although so much less that it
feels nearly absent. I personally like it very much, it is like sitting
in the boat where we really have to push the oars to start recovery.
> Again, a priori, I imagine that being able to adjust the Drag Factor
> must act as a kind of equalizer between the two ergs.
Well, i didn't try that when testing them side by side. I felt a little
difference, as i described in my other post in this thread, and i
managed to eliminate it, at least partly, by adding a weight to the
moving mass of the Dynamic.
> People are always postulating that because a C2 on slides is roughly
> 40% heavier than a RowPerfect, the C2 on slides will "feel" as if you
> are sculling in a tub whereas the RowPerfect will feel as if you are
> sculling in a racing 1x. But, this has not been my experience.
Here i am not sure what you mean by the "tub"... Is it something like these?
http://www.strandkreuzer.de/
No, the difference in the dynamics between C2 on slides and the Dynamic
is not so big. I think i still remember when as a junior i was switching
between my club's racing single sculler 19-20 kg and 13,5 kg Stamepfli i
was using in a national team -- the difference is probably of this kind.
Both -- C2 on slides and the Dynamic -- feel like racing boats, although
there is a difference in "weight". And the difference is felt mostly in
the recovery, not so much in the drive.
--
Yours Virtually, Zibi
Zbigniew A.
>
> However, a substantial & consistent difference in the delivered (i.e.
> monitored) power was measured between the 2 modes with the subject
> rowing at the same heart rate. There was a deficit in both monitored &
> dynamometer computed power in the fixed head setup, amounting (from
> memory) to ~130 watts. This deficit appeared to represent the extra work
> required by the rower in simply accelerating & decelerating his body,
> first up, & then down, the slide every stroke before actually doing any
> work on the handle.
>
> You may agree with me that none of that sounds counter-intuitive?
Oh no, not at all!
All the practical tests, by myself and by others, and the theoretical
works of Valery Kleshnev, confirm advantage of C2 on slides compared to
a fixed one. Both in regard to max power and a cadence. And it is
perfectly understandable. :-)
What i find difficult to comprehend and counter intuitive, is that this
advantage seems to disappear during the longer pieces. Some people
report that they can not repeat their results from a fixed C2 on a
Dynamic. And during my last test side by side at 500m, which is still a
relatively short distance, the advantage of power was gone and the
cadence on Dynamic and C2 on slides was lower. This i don't get.
>
> Anyone wanting to row faster (or to coach others to do so) must be ready
> to create meaningful test scenarios & rigorously evaluate them. This is
> not to hard to do, but if the conclusions depend to any extent on rower
> perception then we risk getting them wrong. I'm not saying you got it
> wrong, but you said your results were counter-intuitive. I feel that a
> flaw in your test protocol was the lack of an absolute measure of
> performance - which only a dynamometer could provide.
>
> What do you think?
Well, frankly, i don't care so much. :-)) I am rather practical person
and the theory behind all this is for me not so important at this point.
I am very glad i've got the new Dynamic and i am confident it is a best
training tool for me, in my situation. All i need now is more time to
use it!
And now i know i can compare my scores from Dynamic with my past results
on C2 on slides directly, without any adjustments. And the monitor works
in a way i am used to... And the memory card too. This is all i need.
Luckily, i don't have to make important choices. If i was to select a
crew according to the erg results, some being made on a stationary and
other on a dynamic, then i would have a problem...
--
Yours Virtually, Zibi
Charles Carroll
Zibi,
"You have to be careful with theory and how it blends with practice.
They�re quite often very different things. There�s not much point in
having a boat that�s two or three seconds faster on paper if people
find it uncomfortable to row."
This comment comes from Greame King. You can find it in an interview
with him in The Independent Rowing News, 9 Dec. 2010.
Off the water I struggle to understand the mathematics and physics in
building boats and oars. These things are fascinating to me and
understanding them better only enriches my sculling.
On water, however, it is a different story. As Greame King says,
theory and practice are quite often very different things. I seem to
confirm this almost every time I go out on the water.
For example, theory encourages us to scull the longest stroke length
we possibly can. But in practice I find that I can move a boat faster
if I keep my feet firmly against the stretcher, even if this means
that I have to scull a little shorter. So it is better for me to scull
in a way that enable me to solidly push off the stretcher than it is
for me to scull in a way that makes me long.
Cordially,
Charles
Carlos
Hello,
Here is good data for you and your crew people about the change that
is coming.
www.carlosdinares.com
http://www.youtube.com/user/rowperfect3
www.rowperfect3.com
Let me know if what you find here is interesting for you and your
rowers.
Thank you,
--
Carlos Dinares
Richard du P
Full marks for consistency!
Richard du P
Justus J.
> ...
> All results were stored on a memory card and analyzed later at home.
By analysing the results, one might overlook the difference: the real
advantage is not getting lower/better RESULTS, but better ROWING
(movement of your arms, legs, body etc.). That's what this whole
"dynamic thing" is all about. To get an idea of the differences there
you'd need a video analysis, or stroke-by-stroke comparison of force curves.
Neither of the set-ups you describe can provide that, as far as I know.
Justus
Tinus
wrote:
> On water, however, it is a different story. As Greame King says,
> theory and practice are quite often very different things. I seem to
> confirm this almost every time I go out on the water.
>
> For example, theory encourages us to scull the longest stroke length
> we possibly can. But in practice I find that I can move a boat faster
I don't believe there are many proper theories which state we have to
row the longest stroke length we possibly can. Of course, if the
theory is wrong then it probably will be different compared to
practice.
Theory and practice should be the same.... in theory.
Charles Carroll
Martijn,
When I stop laughing I will be able to think about what you wrote ...
Warmest regards,
Charles
sully
I guess it depends on what's meant by 'long as possibly can'.
If taken literally, I agree with Tinus, there's nobody theorizing such
a thing,
but in the sense of what I believe Charles to mean, that there's an
optimal
length to row that is taught, and he observes he goes faster if he
rows shorter
than that.
Charles Carroll
>> to
>> row the longest stroke length we possibly can.
> I guess it depends on what's meant by 'long as possibly can'.
> If taken literally, I agree with Tinus, there's nobody theorizing
> such
> a thing,
> but in the sense of what I believe Charles to mean, that there's an
> optimal
> length to row that is taught, and he observes he goes faster if he
> rows shorter
> than that.
Mike,
Exactly!
Where I am now in my sculling it seems to me more important to get a
good solid push off the stretcher with my feet firmly against it than
it is to get a little extra length. I go faster with the good solid
push.
But I suspect that as I get more comfortable with this new found use
of the stretcher, I'll also start getting longer. The problem is that
you have to give these things time, and you cannot do that without
putting in the miles.
Learn to "row true," to start the catch with the feet pressed firmly
against the stretcher and pushing hard, and eventually you will get
longer and longer. But you can only do this if you put in the miles
and focus on every stroke.
But I suspect you know this much better than I do ...
Warmest regards,
Charles
Tinus
wrote:
My comment* is mainly a reaction against the general principle
"You have to be careful with theory and how it blends with practice.
They re quite often very different things."
and I mainly want to make a small case for theory. I feel the
principle needs refinement. What is described by taking care with
theory should already be inherent to theory.
The taking care is not something which you should do specifically
(only) in the case of applying theory to practice. You should also
take care when dealing with theory or practice on their own or when
applying practice to theory. I agree 'one has to take care' but it is
not something about theory, which is labelled different (and wrong)
from practice, that motivates this care. People often speak about
'what is on paper does not always come true'. Theory is often
mentioned, as a matter of speech, instead of this paper. But what is
on paper if often not a complete theory and merely an abstracted
prediction (susceptible to chance) from shortened theory based on a
limited (incomplete) number of variables.
If you base yourself on practice, by for instance testing which stroke
length results into the best speed, how can you be sure that it will
be the same next time? ... You can only assume that it will be the
same next time, which is in fact creation of new theory (or at least
it could be seen in light of the proverbial 'on paper').
*I made use of the example about long strokes but I did not want to
discuss in depth ideas about long strokes and how they may vary among
people or whether what is commonly prescribed is wrong or not. That
would be just one of many aspects in which different formulations
could mangle the case concealing the underlying general and
transcendental relation between theory and practice. If a theory
simply states something like 'you have to move the handle more than
1.5 meters per stroke' than indeed, you should have to take care with
that theory. However if theory states it's shortcomings and is
something like 'for x% of such and such a group of people you will
find an optimum to move the handle more than 1.5 meters' then you
don't have to take care with the theory as care is inherent to the
theory. You can have many theories which fail in this way and you can
have many theories which succeed.
Carl Douglas
Charles -
Being the awkward so & so that I am, I am driven to ask:
How does pressure on the stretcher _before_ there is load on the blades
help?
I know that's popular coaching advice, but here we're discussing
dynamics = inertial mechanics. When a large mass impacts or presses
against a smaller mass, the smaller moves from constant position or
constant velocity by far more than the larger.
Translate that into man & boat, with a mass ratio of 5:1 or more, and it
is the boat which moves - backwards. And the work done in driving the
boat backwards is all wasted.
In short, that's going back to "slide control", "building pressure on
the feet on the recovery" & all those mantras which are irrelevant to
boat propulsion & should apply only to rowing a static erg in a way that
does not damage the knees & lower back.
This is a matter of simple logic - the maths is entirely against the
case you put & is not open to re-interpretation.
So are you, perhaps, replacing one flawed action at the catch with
another which, while flawed, gives you more confidence so it works
better? That is the seductive power of short-term gain. What
ultimately works best may take time to come good, and I've seen so many
rowers go down blind alleys in search of a quick result, only to be
disappointed later. Like the person who thinks the rig is fine (and it
is), but because he has one poor outing then starts fiddling with pitch,
height, spread, etc., & just ends up frustrated. You then take them
back to the original settings and all is fine once more, then the cycle
repeats after the next crappy outing.
Just a thought.
Tinus
> How does pressure on the stretcher _before_ there is load on the blades
> help?
>
> I know that's popular coaching advice, but here
It can be pressure generated during eccentric muscle contraction. Up
to some amount pushing on the stretcher before the catch may be of
importance for reducing energy loss. Also for response time it may
useful to have a sense of pushing against the stretcher before you
actually start loading the blades. This is especially apparent in
something like a start from blocks in track running.
Tinus
That was off-topic. Not trying to argue against the main point
("replacing one flawed action at the catch with
another").
Charles Carroll
> blades help?
Carl,
This is just my clumsy writing.
Shoveling water, slip, moving the blades through water, however you
want to think of it – all that is a simple expense of spirit in a
waste of energy.
As a general principle, putting more load on the blades than they can
support is always a waste of energy. Did I say this correctly?
Rather what I was trying to get at is the idea of “biting off more
than you can chew.” It is an old phrase. Fairbairn uses it frequently.
But in my case it seems especially pertinent.
Let me be specific. In my obsession with front loading the catch I was
getting so far astern that I lost a goodly portion of my contact with
the stretcher and thereby undermined my ability to press solidly
against it once the blades were fully loaded.
Revisiting Fairbairn, then afterwards R. S. de Havilland’s “Elements
of Rowing,” I decided to focus exclusively on keeping my feet firmly
against the stretcher. “Firm on the feet on the stretcher” is de
Havilland’s phrase. De Havilland writes:
“See that the FEET are firm and flat on the stretcher … the stretcher
is as important for rowing against as the ground is for standing on …
Too much stress cannot be laid on this point … There is no hope for
the oarsman who neglects his stretcher; on the other hand a person
firm on his feet will always attract a coach, no matter what failings
there may be.” –de Havilland.
Novice advice I suppose; however, I'll try anything if it looks like
it could make me a better sculler,
But look, I am making this point overly complicated. It is actually
very simple. All I am doing is teaching myself to use my legs better.
And what I have concluded is that learning to use the legs correctly
should precede, not follow, learning to “get long.” Concentrate on
getting a solid push off the stretcher and eventually you will find
yourself getting longer and longer until you are as long as your body
will allow.
By the way, about the coaching mantras you mention – “slide control,”
“building pressure on the feet on the recovery,” etc. – I do want to
emphasize that for the last few weeks I really have been trying to
focus “exclusively” on keeping my feet firm against the stretcher. I
have tried to ignore virtually everything else and just scull.
The idea is to feel ROCK stable at the finish, and ROCK stable during
the recovery, and ROCK stable as I spread the hands apart before
putting the blades in the water, and ROCK stable as I feel the blades
loading, and ROCK stable as I try to match the pressure I build
against the stretcher to the load I am building against the blades.
I just looked at the note I wrote yesterday after I came in off the
water. “Never have I felt more confident, nor have I ever rowed so
well.” I say this because “the feel” of my shell moving through the
water seemed superior to anything I have felt before.
But writing about “the feel” of the shell is subjective.
Objectively, my puddles have never been so far apart. And the timed
interval of the work out has never been so fast. And that’s sculling
against a flood tide!
But as you suggest, today is another day, and what worked yesterday
may not work so well this morning. Is there a sculler in the world who
does not understand this?
Warmest regards,
Charles
Zbigniew A.
> By analysing the results, one might overlook the difference: the real
> advantage is not getting lower/better RESULTS, but better ROWING
> (movement of your arms, legs, body etc.). That's what this whole
> "dynamic thing" is all about.
That goes without saying.
--
Virtually Yours, Zibi