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How important is it to move handle and seat at the same speed on an erg?
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Charles Carroll
May 24, 2013, 3:19:01 AM5/24/13
to
Dear all,
Almost since I began sculling I have heard that in the beginning phases of
the drive the hands and seat should move concurrently at the same speed?
Case in point from “Rowing Faster, Second Edition:”
“In simplest terms, the load on the body of the rower is created between the
handle and the footstretcher during the drive phase. The descending load
from the handle meets the ascending load of the footstretcher, and when
transferred efficiently, the seat and handle move at the same speed, and
distance until the trunk is recruited.” (Chapter 8, Loads on the Bodies of
Rowers, p. 91, Paul Francis)
Or from the same author, same book:
“The early phase of the drive requires the handle and seat to move at the
same speed for the same distance.” (p.101)
In any event, I find that I get my best drives and go my fastest when handle
and seat move at the same speed for the same distance.
So imagine my surprise when this morning I had an email with a link to a
video of someone working on on a RowPerfect. The seat hardly moves at all:
http://www.youtube.com/watch?v=5gKJNhzRGgo&feature=em-uploademail
Same for the Concept 2 Dynamic:
https://www.youtube.com/watch?v=vYY-urDOfFs
On the other hand, on a Concept 2 on slides you can practice moving hands
and seat during the beginning phases of the drive at the same speed to your
heart’s content:
https://www.youtube.com/watch?v=jALCrfoHuaY
It seems to me that it is important to practice on-water rowing technique on
an erg, leastwise it is for me. And I have heard much about how the latest
RowPerfect and Concept 2 Dynamic are improvements over a Concept 2 on
slides. But if the RowPerfect and Concept 2 Dynamic won’t permit me to
practice moving handle and seat at the same speed for the same distance, I
have to say that I have my doubts about what I have heard.
Anyone care to enlighten me?
Cordially (and always curious)
Charles
Almost since I began sculling I have heard that in the beginning phases of
the drive the hands and seat should move concurrently at the same speed?
Case in point from “Rowing Faster, Second Edition:”
“In simplest terms, the load on the body of the rower is created between the
handle and the footstretcher during the drive phase. The descending load
from the handle meets the ascending load of the footstretcher, and when
transferred efficiently, the seat and handle move at the same speed, and
distance until the trunk is recruited.” (Chapter 8, Loads on the Bodies of
Rowers, p. 91, Paul Francis)
Or from the same author, same book:
“The early phase of the drive requires the handle and seat to move at the
same speed for the same distance.” (p.101)
In any event, I find that I get my best drives and go my fastest when handle
and seat move at the same speed for the same distance.
So imagine my surprise when this morning I had an email with a link to a
video of someone working on on a RowPerfect. The seat hardly moves at all:
http://www.youtube.com/watch?v=5gKJNhzRGgo&feature=em-uploademail
Same for the Concept 2 Dynamic:
https://www.youtube.com/watch?v=vYY-urDOfFs
On the other hand, on a Concept 2 on slides you can practice moving hands
and seat during the beginning phases of the drive at the same speed to your
heart’s content:
https://www.youtube.com/watch?v=jALCrfoHuaY
It seems to me that it is important to practice on-water rowing technique on
an erg, leastwise it is for me. And I have heard much about how the latest
RowPerfect and Concept 2 Dynamic are improvements over a Concept 2 on
slides. But if the RowPerfect and Concept 2 Dynamic won’t permit me to
practice moving handle and seat at the same speed for the same distance, I
have to say that I have my doubts about what I have heard.
Anyone care to enlighten me?
Cordially (and always curious)
Charles
mruscoe
May 24, 2013, 4:25:50 AM5/24/13
to
On 24/05/2013 08:19, Charles Carroll wrote:
[snip]
drive (and speed) when the distance between the hands and the seat
doesn't change for the first part of the drive - that can be achieved on
all three of those dynamic rowing machines.
[snip]
>
> In any event, I find that I get my best drives and go my fastest when
> handle
> and seat move at the same speed for the same distance.
>
> So imagine my surprise when this morning I had an email with a link to a
> video of someone working on on a RowPerfect. The seat hardly moves at all:
>
> http://www.youtube.com/watch?v=5gKJNhzRGgo&feature=em-uploademail
>
> Same for the Concept 2 Dynamic:
>
> https://www.youtube.com/watch?v=vYY-urDOfFs
>
> On the other hand, on a Concept 2 on slides you can practice moving hands
> and seat during the beginning phases of the drive at the same speed to your
> heart’s content:
>
> https://www.youtube.com/watch?v=jALCrfoHuaY
>
> It seems to me that it is important to practice on-water rowing
> technique on
> an erg, leastwise it is for me. And I have heard much about how the latest
> RowPerfect and Concept 2 Dynamic are improvements over a Concept 2 on
> slides. But if the RowPerfect and Concept 2 Dynamic won’t permit me to
> practice moving handle and seat at the same speed for the same distance, I
> have to say that I have my doubts about what I have heard.
What's the problem? You are saying that you personally get your best
> In any event, I find that I get my best drives and go my fastest when
> handle
> and seat move at the same speed for the same distance.
>
> So imagine my surprise when this morning I had an email with a link to a
> video of someone working on on a RowPerfect. The seat hardly moves at all:
>
> http://www.youtube.com/watch?v=5gKJNhzRGgo&feature=em-uploademail
>
> Same for the Concept 2 Dynamic:
>
> https://www.youtube.com/watch?v=vYY-urDOfFs
>
> On the other hand, on a Concept 2 on slides you can practice moving hands
> and seat during the beginning phases of the drive at the same speed to your
> heart’s content:
>
> https://www.youtube.com/watch?v=jALCrfoHuaY
>
> It seems to me that it is important to practice on-water rowing
> technique on
> an erg, leastwise it is for me. And I have heard much about how the latest
> RowPerfect and Concept 2 Dynamic are improvements over a Concept 2 on
> slides. But if the RowPerfect and Concept 2 Dynamic won’t permit me to
> practice moving handle and seat at the same speed for the same distance, I
> have to say that I have my doubts about what I have heard.
drive (and speed) when the distance between the hands and the seat
doesn't change for the first part of the drive - that can be achieved on
all three of those dynamic rowing machines.
Henry Law
May 24, 2013, 4:51:19 AM5/24/13
to
On 24/05/13 08:19, Charles Carroll wrote:
> The seat hardly moves at all
True, but this is a rowing machine and not a boat. If my stretcher were
> The seat hardly moves at all
moving /backwards/ with respect to the earth like the one in the clips
I'd be seriously worried.
I think the thing about these dynamic ergos is that they make the rowing
action /feel/ more authentic, and allow some of its elements to be
practiced better; but there are still certain things that are totally
different.
--
Henry Law Manchester, England
johnf...@gmail.com
May 24, 2013, 7:50:39 AM5/24/13
to
On Friday, May 24, 2013 3:19:01 AM UTC-4, Charles Carroll wrote:
> Almost since I began sculling I have heard that in the beginning phases of
> the drive the hands and seat should move concurrently at the same speed?
>
The point of the "dynamic" machines and the slides is to try to make "rowing" on the machine replicate a tad more closely what occurs in a boat. This is done by reducing the accelerated mass by having the feet move rather than the seat: the body stays in one place while the machine (or some part of it) moves back and forth. The mass being accelerated is thus reduced to less than the body's mass.
> Almost since I began sculling I have heard that in the beginning phases of
> the drive the hands and seat should move concurrently at the same speed?
>
Just substitute "feet" for "seat" in the above saying and you'll be good to go.
Carl
May 24, 2013, 10:36:27 AM5/24/13
to
like boats - their dynamics are completely different.
Why are those dynamics different? Simple really. In a boat you have
~15kg of boat, well-lubricated by floating on water, so there's very
little resistance to your feet pushing it around & minimal inertia in
the object your feet are pushing. In a static erg you have the entire
mass of the earth effectively attached to your feet: if we take that in
simple terms, it's 6x10^21 tonnes (6 followed by 21 zeros!) - a huge
amount of inertia - so when you push on the stretcher the stretcher goes
absolutely nowhere.
Isn't that already a big enough difference? Yet we are so brainwashed
by the argument that we can match rowing on a static erg that we
subordinate real life in real boats to what we think best applies to
pulling static ergs. Blinkers, anyone?
So you get folk making up rules for which bits of the body should move
by how much to achieve the perfect stroke, on a static erg. And then
they expect you to to the same in a boat as on the incredibly different
(in inertial terms) beast called a static erg? Surely that's completely
ridiculous?
Now look at the dynamic erg, currently best represented by the
Rowperfect. Attached to your feet is a freely sliding mass not
dissimilar to that of the boat. And, somewhat like the boat, you pull
against that mass with your hands & push it with your feet. So there's
no way that's going to behave or feel like a static erg, but it does
feel & respond to what you do pretty much as a boat does. Which is just
what it claims in the wording on the can. That's surely a good thing?
Now to the movement of the seat:
Just forget about static ergs from here onwards, because whatever their
virtues they don't & can't simulate rowing. Now consider what happens
on the water & compare that with the boat.
You're right that the seat hardly moves on a RP. But don't try to fix
the seat on this machine because, although the movement is small, you'll
come off the seat if that small movement is blocked. There is no way
the rower can or should try to define the amount of seat movement over
time - it just a consequence of a bunch of linked inertial reactions.
Now suppose you're travelling in a launch next to a smooth sculler.
Look through a sight (say a cardboard tube, or a video camera held
steady) & you'll find, surprise!, that her seat doesn't move much
either. What moves, relative to your fixed velocity reference frame, is
the boat, & every other part of the rower except a point near the top of
the pelvis.
But that's the same as you see (& seem to object to) on the RP. So the
RP probably does a tolerable job of simulating the rower.....
We humans have difficulty in separating out the relative motions of
boats, people, oars & water. We are drawn to fixate on the boat & then
to try to relate everything else to the boat. With respect, that
founders under the false assumption, so prevalent in rowing, that the
boat is something fixed which we must pull along & try to accelerate, &
to which we can do almost any crude action without it penalising us
inertially for our folly.
HTH
Carl
--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: tinyurl.com/2tqujf
Email: ca...@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682
URLs: carldouglas.co.uk & now on Facebook @ CarlDouglasRacingShells
James HS
May 24, 2013, 10:46:22 AM5/24/13
to
They are VERY different animals.
A C2 (called a static head) when you push with your legs from compression the whole distance of push is translated into travel of the seat.
On a dynamic erg, from compression, the feet move forward AND the seat moves back, and the hands move back.
Liken this to a boat (I am not going to describe the physics (phew!) but you are pushing against something that can move away from you - so the feet move away and the bum moves in the opposite direction.
The erg instruction that hands and seat should be moving at the same pace is really just saying that you maintain your rock over position in the early parts of the drive - so all of the leg drive should translate into handle drive.
obviously as you add back and then arms the handle moves more and possibly faster than the seat (which actually stops while the handle keeps going.)
On a dynamic and in the boat, this is translated (In my head) to unfurling - i.e. when the leg drives I keep the rock over and then introduce back and arms.
Many times we have discussed that these are not separate discrete movements - and some open earlier than others, but they are actually all proscribing the same sequence.
I have both a dynamic and static C2 and keep the same thing in my mind for both (but WAY prefer the Dynamic)
James
James
johnf...@gmail.com
May 24, 2013, 1:12:28 PM5/24/13
to
I think of the erg as a (poor) substitute for actual sculling when weather or other issues prevent me from doing a scheduled workout on the water. It works some of the same muscle groups, and one can work on a few technical aspects of the rowing stroke. And it's the closest approximation available to us, closer than say a treadmill, a bicycle, an elliptical trainer, swimming, XC skiing, or other aerobic exercises. (Which doesn't mean that it isn't a good idea to do those other activities for cross-training). I'll always prefer an erg which more closely replicates the on-water experience, but I accept that it isn't a perfect simulator for every nuance of actual sculling.
John Greenly
May 24, 2013, 8:51:45 PM5/24/13
to
On Friday, May 24, 2013 3:19:01 AM UTC-4, Charles Carroll wrote:
Carl already did a fine job explaining, but I can't resist giving it a try too. Here goes:
We physicists see trouble ahead when there is talk of motion without defining the reference frame for that motion. That is, talking about motion only makes proper sense when you specify motion with respect to something. That is the fundamental insight on which Einstein built his special theory of relativity- relativity means exactly something moving relative to something else. In our case, when we talk of the hands and seat moving at the same speed, what we mean is that they move at the same speed with respect to the boat: the boat is the "frame of reference". Since the feet are attached to the boat, the feet define the same reference frame.
When there is no boat, as on a dynamic erg, it is hard for our eye to see in the reference frame defined by the feet- they're small, they are going back and forth. But if you keep the angle of your trunk steady and arms steady during the leg drive, then indeed the hands and seat do in fact move at the same speed with respect to the feet- and are stationary with respect to each other, which is really the point. We keep our posture and arms steady during the first part of the leg drive.
In the reference frame of the room with the video camera sitting still in it, the seat is nearly still on the dynamic ergs, and we can see that reference frame more easily: the feet go scooting away on the drive. What we can see easily is the posture relating the hands to the seat, and that's nice because that is what we really care about. In the first two videos you linked, the rower is actually opening his back quite early, so the hands do not stay very still with respect to the seat early in the drive- but that's the rower's technique, and has nothing to do with the erg type.
I'm interested in your description of the third (C2 on slides) video. Here the machine attached to the feet is large enough that your eye is attracted to it, and you more easily see its frame of reference- as in a boat- so it looks like the seat and hands are moving. But if you focus on the wall behind the rower you'll see that the seat is actually nearly stationary (not quite so stationary as the others because the machine is heavier). With respect to the room, actually the feet and the machine are moving, just like on the other dynamic ergs.
An aside: a critical point for understanding the physics of rowing correctly is that the frame of the boat and the feet is an accelerated frame of reference: it is changing speed, oscillating. A lot of the misconceptions about rowing dynamics stem from not recognizing this fact. Getting Newton's laws worked out correctly in a non-uniformly accelerating reference frame is very tricky. If you doubt me, just remember that Einstein needed to work out his magnificent General Theory of Relativity to be able to deal correctly with accelerated reference frames. It's much, MUCH simpler to think about everything about rowing in the reference frame of the rower's butt, which moves, as Carl says, at a more nearly constant speed. Ahhh, yes, I can hear Isaac Newton breathing a sigh of relief....
All this probably is no help at all, but it was a lot of fun to write. Thanks for indulging me!
Cheers,
John G
Message has been deleted
Message has been deleted
Message has been deleted
James HS
May 25, 2013, 10:57:55 AM5/25/13
to
enjoyable to read too!
Carl
May 25, 2013, 11:06:25 AM5/25/13
to
On 25/05/2013 02:29, John Greenly wrote:
> On Friday, May 24, 2013 3:19:01 AM UTC-4, Charles Carroll wrote:
> On Friday, May 24, 2013 3:19:01 AM UTC-4, Charles Carroll wrote:
>> Dear all,
>>
>>
>>
>> Almost since I began sculling I have heard that in the beginning phases of
>>
>> the drive the hands and seat should move concurrently at the same speed?
>>
>>
>>
>> Case in point from �Rowing Faster, Second Edition:�
>>
>>
>>
>> Almost since I began sculling I have heard that in the beginning phases of
>>
>> the drive the hands and seat should move concurrently at the same speed?
>>
>>
>>
>>
>>
>>
>> �In simplest terms, the load on the body of the rower is created between the
>>
>> handle and the footstretcher during the drive phase. The descending load
>>
>> from the handle meets the ascending load of the footstretcher, and when
>>
>> transferred efficiently, the seat and handle move at the same speed, and
>>
>> distance until the trunk is recruited.� (Chapter 8, Loads on the Bodies of
>> handle and the footstretcher during the drive phase. The descending load
>>
>> from the handle meets the ascending load of the footstretcher, and when
>>
>> transferred efficiently, the seat and handle move at the same speed, and
>>
>>
>> Rowers, p. 91, Paul Francis)
>>
>>
>>
>> Or from the same author, same book:
>>
>>
>>
>> �The early phase of the drive requires the handle and seat to move at the
>> Rowers, p. 91, Paul Francis)
>>
>>
>>
>> Or from the same author, same book:
>>
>>
>>
>>
>> same speed for the same distance.� (p.101)
>>
>>
>>
>> In any event, I find that I get my best drives and go my fastest when handle
>>
>> and seat move at the same speed for the same distance.
>>
>>
>>
>> So imagine my surprise when this morning I had an email with a link to a
>>
>> video of someone working on on a RowPerfect. The seat hardly moves at all:
>>
>>
>>
>> http://www.youtube.com/watch?v=5gKJNhzRGgo&feature=em-uploademail
>>
>>
>>
>> Same for the Concept 2 Dynamic:
>>
>>
>>
>> https://www.youtube.com/watch?v=vYY-urDOfFs
>>
>>
>>
>> On the other hand, on a Concept 2 on slides you can practice moving hands
>>
>> and seat during the beginning phases of the drive at the same speed to your
>>
>> heart�s content:
>>
>>
>> In any event, I find that I get my best drives and go my fastest when handle
>>
>> and seat move at the same speed for the same distance.
>>
>>
>>
>> So imagine my surprise when this morning I had an email with a link to a
>>
>> video of someone working on on a RowPerfect. The seat hardly moves at all:
>>
>>
>>
>> http://www.youtube.com/watch?v=5gKJNhzRGgo&feature=em-uploademail
>>
>>
>>
>> Same for the Concept 2 Dynamic:
>>
>>
>>
>> https://www.youtube.com/watch?v=vYY-urDOfFs
>>
>>
>>
>> On the other hand, on a Concept 2 on slides you can practice moving hands
>>
>> and seat during the beginning phases of the drive at the same speed to your
>>
>>
>>
>>
>> https://www.youtube.com/watch?v=jALCrfoHuaY
>>
>>
>>
>> It seems to me that it is important to practice on-water rowing technique on
>>
>> an erg, leastwise it is for me. And I have heard much about how the latest
>>
>> RowPerfect and Concept 2 Dynamic are improvements over a Concept 2 on
>>
>> slides. But if the RowPerfect and Concept 2 Dynamic won�t permit me to
>>
>>
>> https://www.youtube.com/watch?v=jALCrfoHuaY
>>
>>
>>
>> It seems to me that it is important to practice on-water rowing technique on
>>
>> an erg, leastwise it is for me. And I have heard much about how the latest
>>
>> RowPerfect and Concept 2 Dynamic are improvements over a Concept 2 on
>>
>>
>> practice moving handle and seat at the same speed for the same distance, I
>>
>> have to say that I have my doubts about what I have heard.
>>
>>
>>
>> Anyone care to enlighten me?
>>
>>
>>
>> Cordially (and always curious)
>>
>>
>>
>> Charles
>
>> practice moving handle and seat at the same speed for the same distance, I
>>
>> have to say that I have my doubts about what I have heard.
>>
>>
>>
>> Anyone care to enlighten me?
>>
>>
>>
>> Cordially (and always curious)
>>
>>
>>
>> Charles
>
> Hi Charles,
>
> Carl already did a fine job explaining, but I can't resist giving it a try too. Here goes:
>
> We physicists see trouble ahead when there is talk of motion without defining the reference frame for that motion. That is, talking about motion only makes proper sense when you specify motion with respect to something. That is the fundamental insight on which Einstein built his special theory of relativity- relativity means exactly something moving relative to something else. In our case, when we talk of the hands and seat moving at the same speed, what we mean is that they move at the same speed with respect to the boat: the boat is the "frame of reference". Since the feet are attached to the boat, the feet define the same reference frame.
>
> When there is no boat, as on a dynamic erg, it is hard for our eye to see in the reference frame defined by the feet- they're small, they are going back and forth. But if you keep the angle of your trunk steady and arms steady during the leg drive, then indeed the hands and seat do in fact move at the same speed with respect to the feet- and are stationary with respect to each other, which is really the point. We keep our posture and arms steady during the first part of the leg drive.
>
> In the reference frame of the room with the video camera sitting still in it, the seat is nearly still on the dynamic ergs, and we can see that reference frame more easily: the feet go scooting away on the drive. What we can see easily is the posture relating the hands to the seat, and that's nice because that is what we really care about. In the first two videos you linked, the rower is actually opening his back quite early, so the hands do not stay very still with respect to the seat early in the drive- but that's the rower's technique, and has nothing to do with the erg type.
>
> I'm interested in your description of the third (C2 on slides) video. Here the machine attached to the feet is large enough that your eye is attracted to it, and you more easily see its frame of reference- as in a boat- so it looks like the seat and hands are moving. But if you focus on the wall behind the rower you'll see that the seat is actually nearly stationary (not quite so stationary as the others because the machine is heavier). With respect to the room, actually the feet and the machine are moving, just like on the other dynamic ergs.
>
> An aside: a critical point for understanding the physics of rowing correctly is that the frame of the boat and the feet is an accelerated frame of reference: it is changing speed, oscillating. A lot of the misconceptions about rowing dynamics stem from not recognizing this fact. Getting Newton's laws worked out correctly in a non-uniformly accelerating reference frame is very tricky. If you doubt me, just remember that Einstein needed to work out his magnificent General Theory of Relativity to be able to deal correctly with accelerated reference frames. It's much, MUCH simpler to think about everything about rowing in the reference frame of the rower's butt, which moves, as Carl says, at a more nearly constant speed. Ahhh, yes, I can hear Isaac Newton breathing a sigh of relief....
>
> All this probably is no help at all, but it was a lot of fun to write. Thanks for indulging me!
>
> Cheers,
>
> John G
>
I think John's been hit by the "Curse of Google" - that
>
> Carl already did a fine job explaining, but I can't resist giving it a try too. Here goes:
>
> We physicists see trouble ahead when there is talk of motion without defining the reference frame for that motion. That is, talking about motion only makes proper sense when you specify motion with respect to something. That is the fundamental insight on which Einstein built his special theory of relativity- relativity means exactly something moving relative to something else. In our case, when we talk of the hands and seat moving at the same speed, what we mean is that they move at the same speed with respect to the boat: the boat is the "frame of reference". Since the feet are attached to the boat, the feet define the same reference frame.
>
> When there is no boat, as on a dynamic erg, it is hard for our eye to see in the reference frame defined by the feet- they're small, they are going back and forth. But if you keep the angle of your trunk steady and arms steady during the leg drive, then indeed the hands and seat do in fact move at the same speed with respect to the feet- and are stationary with respect to each other, which is really the point. We keep our posture and arms steady during the first part of the leg drive.
>
> In the reference frame of the room with the video camera sitting still in it, the seat is nearly still on the dynamic ergs, and we can see that reference frame more easily: the feet go scooting away on the drive. What we can see easily is the posture relating the hands to the seat, and that's nice because that is what we really care about. In the first two videos you linked, the rower is actually opening his back quite early, so the hands do not stay very still with respect to the seat early in the drive- but that's the rower's technique, and has nothing to do with the erg type.
>
> I'm interested in your description of the third (C2 on slides) video. Here the machine attached to the feet is large enough that your eye is attracted to it, and you more easily see its frame of reference- as in a boat- so it looks like the seat and hands are moving. But if you focus on the wall behind the rower you'll see that the seat is actually nearly stationary (not quite so stationary as the others because the machine is heavier). With respect to the room, actually the feet and the machine are moving, just like on the other dynamic ergs.
>
> An aside: a critical point for understanding the physics of rowing correctly is that the frame of the boat and the feet is an accelerated frame of reference: it is changing speed, oscillating. A lot of the misconceptions about rowing dynamics stem from not recognizing this fact. Getting Newton's laws worked out correctly in a non-uniformly accelerating reference frame is very tricky. If you doubt me, just remember that Einstein needed to work out his magnificent General Theory of Relativity to be able to deal correctly with accelerated reference frames. It's much, MUCH simpler to think about everything about rowing in the reference frame of the rower's butt, which moves, as Carl says, at a more nearly constant speed. Ahhh, yes, I can hear Isaac Newton breathing a sigh of relief....
>
> All this probably is no help at all, but it was a lot of fun to write. Thanks for indulging me!
>
> Cheers,
>
> John G
>
tax-evading/offshoring bunch who (like the late, unlamented "Queen of
Mean", Leona Helmsley), leave the rest of us to pay their taxes for
them, who squeeze competitors & who try to kid us that they own/run Usenet.
John, when I've reached relativistic speeds & then safely returned I'll
hope to report back on RSR on how time-dilation influences ageing & erg
stroke-rates.
Meanwhile I'll pick up on something that Sully posted elsewhere: why do
so many feel it necessary to erg to the mind-numbing, anti-social sound
of loud latter-day musak? Doesn't that alone tell you that ergs (static
ones, anyway) are all about pain & nothing about technique?
Cheers -
John Greenly
May 25, 2013, 2:21:45 PM5/25/13
to
On Saturday, May 25, 2013 11:06:25 AM UTC-4, Carl wrote:
>
> I think John's been hit by the "Curse of Google" - that
>
> tax-evading/offshoring bunch who (like the late, unlamented "Queen of
>
> Mean", Leona Helmsley), leave the rest of us to pay their taxes for
>
> them, who squeeze competitors & who try to kid us that they own/run Usenet.
>
>
>
> John, when I've reached relativistic speeds & then safely returned I'll
>
> hope to report back on RSR on how time-dilation influences ageing & erg
>
> stroke-rates.
>
>
>
> Meanwhile I'll pick up on something that Sully posted elsewhere: why do
>
> so many feel it necessary to erg to the mind-numbing, anti-social sound
>
> of loud latter-day musak? Doesn't that alone tell you that ergs (static
>
> ones, anyway) are all about pain & nothing about technique?
>
>
>
> Cheers -
>
> Carl
Help!! You mean I've gone over to the Dark Side and didn't even know it??
>
> I think John's been hit by the "Curse of Google" - that
>
> tax-evading/offshoring bunch who (like the late, unlamented "Queen of
>
> Mean", Leona Helmsley), leave the rest of us to pay their taxes for
>
> them, who squeeze competitors & who try to kid us that they own/run Usenet.
>
>
>
> John, when I've reached relativistic speeds & then safely returned I'll
>
> hope to report back on RSR on how time-dilation influences ageing & erg
>
> stroke-rates.
>
>
>
> Meanwhile I'll pick up on something that Sully posted elsewhere: why do
>
> so many feel it necessary to erg to the mind-numbing, anti-social sound
>
> of loud latter-day musak? Doesn't that alone tell you that ergs (static
>
> ones, anyway) are all about pain & nothing about technique?
>
>
>
> Cheers -
>
> Carl
Actually, what I said about Einstein was strictly correct. All of Relativity is about the relative motion of different reference frames, and it's all very common-sense stuff. The weird part happened when he added the assumption that the speed of light, c, is the same in all frames. I didn't mention that part because even I, with my extreme rowing prowess, can't go more than 0.00000005 c. Carl, if you can go at a good fraction of c, do report back-- but I warn you, we'll all be long gone, having aged much faster than you.
I tried a Bartok string quartet once for erging music, but in the second movement I began falling off the machine.
--John G
Carl
May 25, 2013, 4:55:12 PM5/25/13
to
On 25/05/2013 19:21, John Greenly wrote:
> On Saturday, May 25, 2013 11:06:25 AM UTC-4, Carl wrote:
>
>>
>> I think John's been hit by the "Curse of Google" - that
>>
>> tax-evading/offshoring bunch who (like the late, unlamented "Queen of
>>
>> Mean", Leona Helmsley), leave the rest of us to pay their taxes for
>>
>> them, who squeeze competitors & who try to kid us that they own/run Usenet.
>>
>>
>>
>> John, when I've reached relativistic speeds & then safely returned I'll
>>
>> hope to report back on RSR on how time-dilation influences ageing & erg
>>
>> stroke-rates.
>>
>>
>>
>> Meanwhile I'll pick up on something that Sully posted elsewhere: why do
>>
>> so many feel it necessary to erg to the mind-numbing, anti-social sound
>>
>> of loud latter-day musak? Doesn't that alone tell you that ergs (static
>>
>> ones, anyway) are all about pain & nothing about technique?
>>
>>
>>
>> Cheers -
>>
>> Carl
>
> Help!! You mean I've gone over to the Dark Side and didn't even know it??
Only in the sense that Google made you post the same very thoughtful
> On Saturday, May 25, 2013 11:06:25 AM UTC-4, Carl wrote:
>
>>
>> I think John's been hit by the "Curse of Google" - that
>>
>> tax-evading/offshoring bunch who (like the late, unlamented "Queen of
>>
>> Mean", Leona Helmsley), leave the rest of us to pay their taxes for
>>
>> them, who squeeze competitors & who try to kid us that they own/run Usenet.
>>
>>
>>
>> John, when I've reached relativistic speeds & then safely returned I'll
>>
>> hope to report back on RSR on how time-dilation influences ageing & erg
>>
>> stroke-rates.
>>
>>
>>
>> Meanwhile I'll pick up on something that Sully posted elsewhere: why do
>>
>> so many feel it necessary to erg to the mind-numbing, anti-social sound
>>
>> of loud latter-day musak? Doesn't that alone tell you that ergs (static
>>
>> ones, anyway) are all about pain & nothing about technique?
>>
>>
>>
>> Cheers -
>>
>> Carl
>
> Help!! You mean I've gone over to the Dark Side and didn't even know it??
post 4 times.
>
> Actually, what I said about Einstein was strictly correct. All of Relativity is about the relative motion of different reference frames, and it's all very common-sense stuff. The weird part happened when he added the assumption that the speed of light, c, is the same in all frames. I didn't mention that part because even I, with my extreme rowing prowess, can't go more than 0.00000005 c. Carl, if you can go at a good fraction of c, do report back-- but I warn you, we'll all be long gone, having aged much faster than you.
>
> I tried a Bartok string quartet once for erging music, but in the second movement I began falling off the machine.
>
> --John G
>
to music?
John Greenly
May 25, 2013, 5:14:16 PM5/25/13
to
On Saturday, May 25, 2013 4:55:12 PM UTC-4, Carl wrote:
> I guess that'd be the Allegro in Op17 #2? But why'd anyone want to erg
>
> to music?
>
>
>
> Cheers -
>
> Carl
Okay, you got me, I made that up (I was thinking of the prestissimo of #4). I've never actually used music with erging. I can't imagine wanting to ruin a piece of music by associating it with that torture machine.
> I guess that'd be the Allegro in Op17 #2? But why'd anyone want to erg
>
> to music?
>
>
>
> Cheers -
>
> Carl
Cheers,
John
Charles Carroll
May 26, 2013, 4:19:01 AM5/26/13
to
Dear Carl,
You offer your usual admirably well-reasoned arguments full of serviceable
insights. I am always grateful for your posts. Over the years I have learned
a lot from them. Indeed they are one of my principle sources about rowing
and sculling. Much of the little I know about the sport comes from you. As
you know, I quote from your posts all the time.
That said, I want to demur on two things in your post.
First, I purposely did not say anything about static ergs in my original
post. I actually don’t see how static ergs play any part in this discussion,
aside from needlessly complicating it.
And second, I tried as hard as I could in my original post to keep a
disinterested tone. I have a question that I am thinking about and I am
doing my best to understand it, and I was hoping that the rsr brain trust
might shed some light into the dark cave of my ignorance. The one thing I
hoped to avoid is an argument over which erg is the best.
Now, in discussing the movement of the seat, you write “consider what
happens on the water.” And that happens to be what I was trying to do.
As Steve Fairbairn said consider: “The important thing in reading rowing is
not to swallow everything as if it were gospel truth, but to read, mark,
learn, and inwardly digest. One need not confine one’s reading to books that
one agrees with; one finds food for thought mostly by disagreement. In fact,
one should read critically, and think whether doing in a boat what one is
reading would help or not, and then try it in a boat and stick to it if it
helps.” (“The Complete Steve Fairbairn,” p. 144)
And that pretty much describes what I have tried to do ever since I started
sculling. I attend to what people have to say. If something seems right to
me, then I try it out on water. In fact I frequently think of my time
on–water in your beautiful shell as time in a laboratory.
So here is what I have learned in my on-water sculling laboratory:
1) If I break my arms too early at the catch, my drive suffers and I go
slower.
2) If I have not prepared my body at the catch, my drive suffers and I go
slower.
3) If I open my back too much at the start of the drive, my drive suffers
and I go slower.
4) If I allow my back and shoulders to be passive and just push off the
stretcher with my legs — i.e. shoot the slide — my drive suffers and I go
slower.
5) If, however, I recruit as many of the muscles as I can in my trunk,
and brace them tight — that is, prepare them such that they work together —
my drive improves and I go faster. I have also observed in my on-water
sculling laboratory that whenever this happens, my hands and seat in the
early phases of the drive travel the same distance at the same speed until
just before my knees are down.
I readily concede that the place I occupy in our little sport is at the
bottom of the pyramid. Perhaps if I shared a place near the peak with the
elite scullers of our sport, my observations would be different. But as I
don’t, they are not.
My questions remain:
1) Is it desirable to have hands and seat in the early phases of the
drive travel the same distance at the same speed until just before my knees
are down?
2) And if so, then it is desirable to design an off-water training device
that simulates this movement?
I have been sculling on water for almost a decade. I am acutely aware that I
know of no erg that perfectly simulates sculling on water. But when an erg
is in the process of being designed, should the two above question be taken
into consideration?
Re the example of travelling in a launch next to a smooth sculler. As you
say, looking just at the seat through this fixed velocity reference frame
the seat appears not to be moving. But this example could hardly be called
inclusive because it is concerned exclusively with the seat. My question
concerns both the hands and the seat.
Specifically I am concerned with what happens to the distance between the
hands and the seat during the beginning phases of the drive. Through a fixed
velocity reference frame, if the hands and feet are moving at the same
speed, then neither would appear to be moving, that is, in the beginning
phases of the drive. Eventually of course, as the knees come down, the
distance between the hands and seat will change, and the hands will move
faster than the seat.
Of course you can move the hands faster or slower than the seat in the
beginning phases of the drive. I call this losing the connection — i.e. the
connection between the hands and the seat.
Now to return to the question of ergs. I would want an off water training
device for on water rowers that would help me train to keep this connection.
And what I do not understand about sliding head ergs with seats that do not
move much, is how they help you train to keep this connection.
Warmest regards,
Charles
You offer your usual admirably well-reasoned arguments full of serviceable
insights. I am always grateful for your posts. Over the years I have learned
a lot from them. Indeed they are one of my principle sources about rowing
and sculling. Much of the little I know about the sport comes from you. As
you know, I quote from your posts all the time.
That said, I want to demur on two things in your post.
First, I purposely did not say anything about static ergs in my original
post. I actually don’t see how static ergs play any part in this discussion,
aside from needlessly complicating it.
And second, I tried as hard as I could in my original post to keep a
disinterested tone. I have a question that I am thinking about and I am
doing my best to understand it, and I was hoping that the rsr brain trust
might shed some light into the dark cave of my ignorance. The one thing I
hoped to avoid is an argument over which erg is the best.
Now, in discussing the movement of the seat, you write “consider what
happens on the water.” And that happens to be what I was trying to do.
As Steve Fairbairn said consider: “The important thing in reading rowing is
not to swallow everything as if it were gospel truth, but to read, mark,
learn, and inwardly digest. One need not confine one’s reading to books that
one agrees with; one finds food for thought mostly by disagreement. In fact,
one should read critically, and think whether doing in a boat what one is
reading would help or not, and then try it in a boat and stick to it if it
helps.” (“The Complete Steve Fairbairn,” p. 144)
And that pretty much describes what I have tried to do ever since I started
sculling. I attend to what people have to say. If something seems right to
me, then I try it out on water. In fact I frequently think of my time
on–water in your beautiful shell as time in a laboratory.
So here is what I have learned in my on-water sculling laboratory:
1) If I break my arms too early at the catch, my drive suffers and I go
slower.
2) If I have not prepared my body at the catch, my drive suffers and I go
slower.
3) If I open my back too much at the start of the drive, my drive suffers
and I go slower.
4) If I allow my back and shoulders to be passive and just push off the
stretcher with my legs — i.e. shoot the slide — my drive suffers and I go
slower.
5) If, however, I recruit as many of the muscles as I can in my trunk,
and brace them tight — that is, prepare them such that they work together —
my drive improves and I go faster. I have also observed in my on-water
sculling laboratory that whenever this happens, my hands and seat in the
early phases of the drive travel the same distance at the same speed until
just before my knees are down.
I readily concede that the place I occupy in our little sport is at the
bottom of the pyramid. Perhaps if I shared a place near the peak with the
elite scullers of our sport, my observations would be different. But as I
don’t, they are not.
My questions remain:
1) Is it desirable to have hands and seat in the early phases of the
drive travel the same distance at the same speed until just before my knees
are down?
2) And if so, then it is desirable to design an off-water training device
that simulates this movement?
I have been sculling on water for almost a decade. I am acutely aware that I
know of no erg that perfectly simulates sculling on water. But when an erg
is in the process of being designed, should the two above question be taken
into consideration?
Re the example of travelling in a launch next to a smooth sculler. As you
say, looking just at the seat through this fixed velocity reference frame
the seat appears not to be moving. But this example could hardly be called
inclusive because it is concerned exclusively with the seat. My question
concerns both the hands and the seat.
Specifically I am concerned with what happens to the distance between the
hands and the seat during the beginning phases of the drive. Through a fixed
velocity reference frame, if the hands and feet are moving at the same
speed, then neither would appear to be moving, that is, in the beginning
phases of the drive. Eventually of course, as the knees come down, the
distance between the hands and seat will change, and the hands will move
faster than the seat.
Of course you can move the hands faster or slower than the seat in the
beginning phases of the drive. I call this losing the connection — i.e. the
connection between the hands and the seat.
Now to return to the question of ergs. I would want an off water training
device for on water rowers that would help me train to keep this connection.
And what I do not understand about sliding head ergs with seats that do not
move much, is how they help you train to keep this connection.
Warmest regards,
Charles
Charles Carroll
May 26, 2013, 5:03:19 AM5/26/13
to
Dear John,
I do not think I could have written what I just posted to Carl without your
post. You explanations have been immensely helpful. You make me regret that
I didn�t pay more attention in my physics tutorials.
You are quite right about the video of the C2 on slides. Once I became
accustomed to a C2 on slides, I found that I hardly move while I erg .
Instead I try to move the erg back and forth underneath me.
But I do not think that the nearly stationary seat of a C2 on slides is
relevant to my question. In the beginning phases of the drive it is not too
difficult to keep a connection between the hands and the seat when you train
on a C2 on slides. Actually it is surprisingly easy to match the movement of
the hands and seat on this erg.
Tom Bohrer in the May 2006 �Rowing News� suggests something he calls a strap
drill. Do you see a way to do such drills on a sliding heard erg? I confess
I can�t. I just don�t see how it is possible to match the movement of the
hands to the seat on such ergs.
http://books.google.com/books?id=BEsEAAAAMBAJ&lpg=PA28&dq=shooting%20the%20slide%20drill%20rowing&pg=PA28#v=onepage&q=shooting%20the%20slide%20drill%20rowing&f=false
Also you might want to take a look at the Rower�s Shadow. How could you use
a Rower�s Shadow on a sliding head erg?
http://www.youtube.com/watch?v=zqA1ZHgFzdo
Now that I have looked at the above video I remember that I owe Tom Kiefer
an email. Arrrrgh! I completely forgot that Tom is using the Rower�s Shadow
in Boston with his adaptive rowers. Mike Sullivan might be interested in
learning that Tom is having a lot of success using this tool with a couple
of blind scullers he is coaching. I�ll have to write to Mike and see if he
wants to borrow mine �
Cordially,
Charles
I do not think I could have written what I just posted to Carl without your
post. You explanations have been immensely helpful. You make me regret that
I didn�t pay more attention in my physics tutorials.
You are quite right about the video of the C2 on slides. Once I became
accustomed to a C2 on slides, I found that I hardly move while I erg .
Instead I try to move the erg back and forth underneath me.
But I do not think that the nearly stationary seat of a C2 on slides is
relevant to my question. In the beginning phases of the drive it is not too
difficult to keep a connection between the hands and the seat when you train
on a C2 on slides. Actually it is surprisingly easy to match the movement of
the hands and seat on this erg.
Tom Bohrer in the May 2006 �Rowing News� suggests something he calls a strap
drill. Do you see a way to do such drills on a sliding heard erg? I confess
I can�t. I just don�t see how it is possible to match the movement of the
hands to the seat on such ergs.
http://books.google.com/books?id=BEsEAAAAMBAJ&lpg=PA28&dq=shooting%20the%20slide%20drill%20rowing&pg=PA28#v=onepage&q=shooting%20the%20slide%20drill%20rowing&f=false
Also you might want to take a look at the Rower�s Shadow. How could you use
a Rower�s Shadow on a sliding head erg?
http://www.youtube.com/watch?v=zqA1ZHgFzdo
Now that I have looked at the above video I remember that I owe Tom Kiefer
an email. Arrrrgh! I completely forgot that Tom is using the Rower�s Shadow
in Boston with his adaptive rowers. Mike Sullivan might be interested in
learning that Tom is having a lot of success using this tool with a couple
of blind scullers he is coaching. I�ll have to write to Mike and see if he
wants to borrow mine �
Cordially,
Charles
Carl
May 26, 2013, 11:15:09 AM5/26/13
to
On 26/05/2013 09:19, Charles Carroll wrote:
> Dear Carl,
>
> You offer your usual admirably well-reasoned arguments full of
> serviceable insights. I am always grateful for your posts. Over the
> years I have learned a lot from them. Indeed they are one of my
> principle sources about rowing and sculling. Much of the little I know
> about the sport comes from you. As you know, I quote from your posts all
> the time.
>
> That said, I want to demur on two things in your post.
>
> First, I purposely did not say anything about static ergs in my original
> post. I actually don’t see how static ergs play any part in this
> discussion, aside from needlessly complicating it.
Please remember, Charles, that while you & I will understand the text,
> Dear Carl,
>
> You offer your usual admirably well-reasoned arguments full of
> serviceable insights. I am always grateful for your posts. Over the
> years I have learned a lot from them. Indeed they are one of my
> principle sources about rowing and sculling. Much of the little I know
> about the sport comes from you. As you know, I quote from your posts all
> the time.
>
> That said, I want to demur on two things in your post.
>
> First, I purposely did not say anything about static ergs in my original
> post. I actually don’t see how static ergs play any part in this
> discussion, aside from needlessly complicating it.
subtext & context, there are many visitors, casual & otherwise, who
haven't a clue what a dynamic erg is or what the difference between ergs
might be. So I try always to include their interests in my responses -
even if that does somewhat complicate my answers :(
>
> And second, I tried as hard as I could in my original post to keep a
> disinterested tone. I have a question that I am thinking about and I am
> doing my best to understand it, and I was hoping that the rsr brain
> trust might shed some light into the dark cave of my ignorance. The one
> thing I hoped to avoid is an argument over which erg is the best.
designed to prove who's hardest, & another machine which rewards you for
rowing well. ;)
few months back, if I may?
There's nothing useful, nor implicitly correct, about maintaining the
same apparent back position through any part of the stroke. What
determines the back alignment is not the back muscles - it is how you
subconsciously change the angle between pelvis & femur as the legs are
driven down. Think about that: as your knees go down the femur goes
from some 70 deg to the horizontal to around flat & only the miscles
acting around the hip axis - which have no connection with or
understanding of what's horizontal - will determine how the back's
apparent alignment with some totally irrelevant horizon will vary.
When we talk about back posture (or shin alignment) WRT the horizon, we
make a completely inappropriate assumption - that the back is somehow
connected to the seat or slide-bed & that we lever it back, or not, with
muscles which somehow connect with something connected with the
horizontal plane. That'd be quite wrong!
As the legs go down the angle between back & femur changes continuously
(unless we do a monstrous bum-shove!). There is no extra or extraneous
effort required to open that entirely fictional back angle by a few
degrees, or not to open it. As I've said before, that supposed "opening
of the back" is yet another of those many things in rowing that we think
we see, that folk discuss endlessly, but which are simple misconceptions.
I know that's awfully hard stuff to smuggle past the barbed-wire topped,
steel-reinforced concrete wall of preconceptions, but it's necessary to
do so if we are to fully understand the mechanics & dynamics of the
rowing stroke.
> I have been sculling on water for almost a decade. I am acutely aware
> that I know of no erg that perfectly simulates sculling on water. But
> when an erg is in the process of being designed, should the two above
> question be taken into consideration?
that a technical difference between a particular sculler & some
supposedly authoritative textbook does not change that.
>
> Re the example of travelling in a launch next to a smooth sculler. As
> you say, looking just at the seat through this fixed velocity reference
> frame the seat appears not to be moving. But this example could hardly
> be called inclusive because it is concerned exclusively with the seat.
> My question concerns both the hands and the seat.
>
> Specifically I am concerned with what happens to the distance between
> the hands and the seat during the beginning phases of the drive. Through
> a fixed velocity reference frame, if the hands and feet
are moving at
> the same speed, then neither would appear to be moving, that is, in the
> beginning phases of the drive. Eventually of course, as the knees come
> down, the distance between the hands and seat will change, and the hands
> will move faster than the seat.
>
> Of course you can move the hands faster or slower than the seat in the
> beginning phases of the drive. I call this losing the connection — i.e.
> the connection between the hands and the seat.
With great respect, Charles, there is no conceivable connection between
> the same speed, then neither would appear to be moving, that is, in the
> beginning phases of the drive. Eventually of course, as the knees come
> down, the distance between the hands and seat will change, and the hands
> will move faster than the seat.
>
> Of course you can move the hands faster or slower than the seat in the
> beginning phases of the drive. I call this losing the connection — i.e.
> the connection between the hands and the seat.
hands & seat, since you are not screwed onto the seat & the seat is
purely a device to save your rump from wear & friction against the
slide-bed - it is in short just a lubricant. And if the hands move
faster than the seat, I'd say that has to indicate an even stronger
connection, & I'll try to explain why:
The power stroke is surely a messy affair, but we must make the best of
it that we can:
1. What we do first is decelerate the boat (the check) as we make an
inevitably slightly clumsy engagement of the blades. One reason for the
check is that the oar shafts are not rigid, so however rapidly we try to
load the blades there's a period during which the tendency to load the
stretcher as a means to loading the hands (& we can discuss the possible
flaws in that at another time) must check the boat as energy goes into
bending the shafts before the load you'd meant to apply is actually felt
by the blades.
2. Then you my extend the check by driving won the legs, so the boat
continues going slower than the body, but the body hardly accelerates.
3. If you do maintain the apparent back posture that you had at the
catch, then you'll start to accelerate the entire body & the seat will
seem to move slightly to the bow. If you do allow the back/femur angle
to open, then the seat (or maybe the top of the pelvis) may not seem to
move at all WRT a constant-velocity reference frame since the
significant upper body mass is being moved ahead faster than everything
else.
4. Once the visual perception of the back alignment rotates towards the
bow, then the seat may indeed seem static.
5. As the hands draw in, the boat does accelerate as ultimately it has
to be travelling at the same speed as the rower, their hands & every
other part of the body at the point of the finish
>
> Now to return to the question of ergs. I would want an off water
> training device for on water rowers that would help me train to keep
> this connection. And what I do not understand about sliding head ergs
> with seats that do not move much, is how they help you train to keep
> this connection.
>
> Warmest regards,
>
> Charles
>
of which you write is about connecting the hands to the inert mass of
the body & through the feet to the boat.
When you lift a weights bar you don't have a seat & so there is no seat
with which to have even a notional connection, yet some if the actions
are not so dissimilar to rowing. When lifting you try to do so in the
manner most efficient for that purpose: this involves lifting also every
bit of the body except the feet, so there are lots of significant masses
other than the weights bar to be considered, & those masses are
encountering force reactions (loads) due not only to their static masses
but to the inertial reactions from their being first accelerated & then
decelerating as the lift is completed.
If you were to rotate that action through 90 degrees so it looks like a
rowing action, you'd need a seat, but you'd still not be supposing some
magical connection, postural or otherwise, between hands & seat. You
would, however, have a very different set of loads since gravity would
not be either helping nor hindering the (now horizontal) lift. It'd be
easier to get the weights bar (presumed to be sitting supported on a
frictionless horizontal track?) moving 'cos you wouldn't be working
against gravity. And you'd have a lot of work to do to stop the bar
from continuing past your head as gravity is not there to decelerate it.
But do you think anyone would be telling you to hold a particular back
posture WRT the horizon? I doubt it.
Well, rowing is different yet again, because now you're working against
a real frictional resistance, not trying to accelerate a friction-free
mass. But still the seat is just a handy artefact, a useful bit of kit,
& no more. And certainly nothing to which to imagine yourself in any
way connected. Indeed, when you are pulling your hardest you're hardly
in contact with the seat anyway.
I'm sure that's quite a basin-full of analogies & seemingly abstruse
argument, so I don't expect it to be easily digested. That said, I
think it's worth careful consideration before anyone tries to discount
it. Yet again, I'm trying to disentangle what we like or are told to
believe from what physics tells us is actually happening, which is never
a particularly palatable offering. Sorry 'bout that :)
Cheers -
John Greenly
May 26, 2013, 12:13:43 PM5/26/13
to
Thanks! it's nice to hear that my meanderings were useful. And thanks for pointing out the interesting strap drill and the neat seat-reference invention. I suspect you are going to think I'm crazy, but in fact both of these would work just fine on any of the dynamic ergs.
I use a dynamic erg myself, an Oartec Slider, so I do know what happens on these machines, and how they look and feel to the rower. You've used a C2 on slides, and the others are very similar, only the moving part is smaller and lighter, closer to a boat's mass, so your seat moves even a bit less with respect to the floor.
Try for a minute to forget what you are seeing on those videos of dynamic ergs from the outside frame of reference. Let your reference frame be yourself- your head- as you are using your C2 on slides. You say that you hardly move, and the machine moves back and forth. That's exactly correct, and it is simple and easy to see and feel. So, to keep the steady relationship between hands and seat, and get the good connection through to the legs drive, what you see and feel is, as you describe, sitting still and pushing the machine away with your legs. Nice! And that's exactly what happens on all the dynamic ergs. I find it almost easier to see and feel than in a boat. If you close your eyes, the feel is very boat-like (MUCH more so than on a static erg where you feel yourself oscillating back and forth).
So, just remember- in the boat, your seat is traveling at nearly constant speed with respect to the water and the boat is oscillating underneath you. On a dynamic erg, your seat is traveling at a nearly constant speed with respect to the floor- that speed happens to be zero- and the machine is oscillating. So on the machine, if the rest of your body and arms are also traveling at that speed- zero- then you are keeping the seat-hand relationship you want. Simple, and easy to see and feel. You could certainly put a strap from seat to handle, or use that neat seat-reference-frame gadget. But since you are nearly stationary in the room, actually a mirror off to the side I bet would work pretty well- you could just watch your reflection, and see that your body and arms stay still during the leg drive.
Yes?
Cheers,
John G
Sarah Harbour
May 26, 2013, 3:38:09 PM5/26/13
to
^snip^
> Well, there's no argument there. There's a brutal torture device
>
> designed to prove who's hardest, & another machine which rewards you for
>
> rowing well. ;)
>
>
I'll leave the rest of you to come to your own conclusions on what that shows!
Sarah
> Well, there's no argument there. There's a brutal torture device
>
> designed to prove who's hardest, & another machine which rewards you for
>
> rowing well. ;)
>
>
> I think that RP does a very good job of simulating the rowing stroke, &
>
> that a technical difference between a particular sculler & some
>
> supposedly authoritative textbook does not change that.
>
>
>
I must say that I was mildly amused by the reviews of various ergs in the Jan/Feb/March issues of British Rowing's "Rowing and Regatta". The RP3 was praised for being the closest to feeling like actual on-water rowing, but right at the end of the review, it was stated that pretty much everyone said that they wouldn't want to do a 2k test on one...
>
> that a technical difference between a particular sculler & some
>
> supposedly authoritative textbook does not change that.
>
>
>
I'll leave the rest of you to come to your own conclusions on what that shows!
Sarah
Carl
May 26, 2013, 4:30:39 PM5/26/13
to
On 26/05/2013 16:15, Carl wrote:
> On 26/05/2013 09:19, Charles Carroll wrote:
<snipped>
> On 26/05/2013 09:19, Charles Carroll wrote:
I'll note, from the video link in the Lower Back Pain thread, the
failure of that sculler to maintain any semblance of a fixed
relationship between hands & seat. He rotates the back WRT the horizon
at a pretty constant rate from catch to finish. Of course his back
problem is not part of this present argument (although worthy of every
rower's proper consideration) but, looking at the video and relating
what he does to his erging results, I'd suggest that it might not be
holding him back too much.
I'm equally impressed by his saying he wouldn't rush to tell Olaf Tufte
to scull with a straighter back.
John Greenly
May 26, 2013, 5:16:18 PM5/26/13
to
The various dynamic ergs seem to have made differing choices about this mass. Both the RP and Oartec include the flywheel assembly in the moving mass, but C2 doesn't. I have heard a number of complaints that the C2 feels "too light" or "slips" at the catch, and I wonder if this might be because the moving mass is just too light. The moving mass on the Oartec slider is actually heavier than a single, around 50 lb if I remember correctly, and it feels to me, if anything, a bit too light at the catch with a drag factor that's good in the middle of the drive. I don't know what the moving mass of the RP3 is.
Any comments from the experts?
thanks,
John G
Charles Carroll
May 26, 2013, 7:57:05 PM5/26/13
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> I'll note, from the video link in the Lower Back Pain thread, the failure
> of that sculler to maintain any semblance of a fixed relationship between
> hands & seat. He rotates the back WRT the horizon at a pretty constant
> rate from catch to finish
But Carl,
> of that sculler to maintain any semblance of a fixed relationship between
> hands & seat. He rotates the back WRT the horizon at a pretty constant
> rate from catch to finish
Isn’t there always a risk of spotting a fault in a quick rower and thus
justifying its existence in not so quick rowers?
Couldn’t resist …
Charles
Carl
May 27, 2013, 8:01:03 AM5/27/13
to
In the specific case, I'd like it better argued - which was my reason
for creating that diversion.
What I'd suggest is that much of this postural stuff is neither here nor
there & that coaches should eschew it. But I did think the
Chiropractor's remarks on the undesirability (for health, not
performance, reasons) of rowing with a curved back made a lot of sense.
I think we should especially avoid nit-picking doctrines which, for no
cogent reason, say hands & feet should travel at the same speed, or that
hands should go away at the speed they come in. Both are based on whim,
not logic or fact. They are about style, not technique, but races are
won by guts & good, simple technique, not on points awarded for style.
What I mean there is that, in the postural case, the idea that the body
angle WRT the horizon means anything is impossible to substantiate since
the horizon means nothing to the body. With finishes the simple fact is
that hands come transiently to a halt at the finish. They tend to go
horizontally out after that (since they halt when the blades are already
clear of the water) & do _not_, either in fact or of necessity, follow
some magical loop. Yet we are so indoctrinated & so reluctant to look &
report on what we really see that we easily kid ourselves to the contrary.
Carl
May 27, 2013, 9:23:57 AM5/27/13
to
1. Your analogue for the frictional drag on the boat & the consequent
energy dissipation through fluid friction is the flywheel. In theory it
decelerates in a similar way to the boat & re-energising it after it has
had the recovery time to spin down makes your catch slower & heavier.
2. Your analogue to the inertia of the boat is the combined mass of the
sliding head + flywheel.
3. You are the analogue of yourself in the boat
4. The stroke's continuously-variable gearing is not incorporated in the
machine. There's a tendency to get the apparent gearing (i.e. the
relationship speed, acceleration & load) right at the catch, but it
become increasingly incorrect thereafter.
5. The gearing mismatch is most evident at the finish, which tends to be
too soft & fast.
There's more to it than that, but I think that is a fair 1st-order
summary. The machine isn't perfect (despite its name), but it beats
anything else until you step into a boat - whereupon you're in an
entirely different & better world :)
We can perhaps elaborate on the power absorption element:
1. Frictional drag force on a hull is, as a first approximation,
proportional to velocity squared, so power is consumed in proportion to
velocity cubed.
2. Turbomachines (e.g. rotating fans, blowers, compressors, etc., with
properly designed aerodynamic surfaces & which move & compress air
through dynamic processes) tend to have 'sweet spots' in their operating
envelopes of speed vs power consumed & thus depart from the desired V^3
power absorption profile. They can be relatively quiet, which is good
on ergs (unless you want to drown out someone's boom-box), but their
power/velocity relationships mean they're not particularly good drag
analogues
3. Really crude air-mashing devices, such as the flat-paddle bladed
spinning disk of the RP, may be relatively noisy but they do tend to
have power/velocity profiles closer to the required V^3 relationship.
4. All moving head machines suffer from seriously compromised intake
conditions.
a) Most turbomachinery induces spiral flows significantly before the
air actually enters the fan, but if the head is moving to & from this is
like moving the bath plughole around the bottom of the bath - the vortex
is chasing the intake, which can't be good for consistent power absorption
b) A lot of effort goes into intake design for well-made fans & axial
& radial compressors, whereas on ergs we see intake shutters which are a
fluid-dynamicist's worst nightmare. Indeed, such fans can give
different aerodynamic power absorption characteristics depending on
whether they are accelerating or decelerating & by how much. So
technique may alter results
5. Most ergs (dynamic or otherwise) do not use direct power measurement
but rely on derivative calculations based on the known moment of inertia
of the fan/flywheel & the rate of spin-down during recovery, so they are
self re-calibrating but this may not be the best way to measure power input
You can easily create an erg to simulate the variable gearing of the
rowing stroke & the rotation of the hands about the axis of the pin.
You can also provide other more compact forms of energy absorption, as
used e.g. in bike trainers, but in rowing we seem to like our machines big.
How's that for starters?
Carl
May 27, 2013, 9:26:39 AM5/27/13
to
On 27/05/2013 13:01, Carl wrote:
Now I'm at it!
Now I'm at it!
for no
> cogent reason, say hands & feet should travel at the same speed,
I meant to write "hands & seat", but there I go!
> cogent reason, say hands & feet should travel at the same speed,
John Greenly
May 27, 2013, 11:37:14 AM5/27/13
to
This confirms what I thought I understood about the masses and inertias involved. It's true that the gearing is also wrong at the finish, but somehow to me on the oartec machine, I notice the catch more.
In thinking about Charles' initial question on this thread I looked at a bunch of videos. There are several on YouTube of really good scullers on the dynamic ergs, both RP and Oartec. I was interested to see that, as with the two videos Charles gave us, most of them were opening their back angle quite promptly at the catch, and in fact I was able to compare their real sculling in race videos, and it looks to me that they do not open the back as promptly in the boat. I don't want to get into the issue of when and how much one should optimally open the back angle because I'm no expert. But I wonder if the unrealistic lightness of the catch on the machines is encouraging people to engage the back swing right away as a way of getting the load up quickly. I think I can feel that tendency myself.
We could make also make this argument about the moving mass: given that the inertia is provided both by the moment of inertia of the flywheel- transformed through its gearing- and by the moving mass, then the effective sum of those two needs to feel like a boat, meaning that the moving mass would have to be less than the boat mass. That would say that my Oartec slider is too heavy. I wonder. What is the RP moving mass- anybody know?
I had also wondered about how close to the idealized V^3 power law these fans are-- interesting.
Of course, even if you did make variable gearing to the flywheel of an RP, for example, you still wouldn't have the motion of moving the hands inward towards each other to load the oars at the catch, and really I suspect that's the lack that bothers me the most about the machine, especially since I've been working on that in the boat this year.
Yes, it seems that short of actually introducing the geometry of the oar handle and pivot, these dynamic machines are about as good as it will get. And they sure are a huge step above the static version.
thanks,
John G
Charles Carroll
Jun 2, 2013, 7:29:43 PM6/2/13
to
> I think we should especially avoid nit-picking doctrines which, for no
> cogent reason, say hands & feet should travel at the same speed, or that
> hands should go away at the speed they come in. Both are based on whim,
> not logic or fact. They are about style, not technique, but races are won
> by guts & good, simple technique, not on points awarded for style.
Carl,
> cogent reason, say hands & feet should travel at the same speed, or that
> hands should go away at the speed they come in. Both are based on whim,
> not logic or fact. They are about style, not technique, but races are won
> by guts & good, simple technique, not on points awarded for style.
Absolutely agree!
It is easy to forget the distinction between doing the deed itself and the
evidence of the deed’s having been done. There is a difference. The two are
not the same.
The objective is not to pull the hands and the seat at the same speed in the
beginning phases of the drive.
If, however, the hands and seat do travel at the same speed, this is
evidence that a sculler or rower has prepared his body well and is using it
correctly in the beginning phases of the drive. In other words it indicates
to whoever may be watching that the sculler or rower has recruited all his
muscles and is employing these muscles correctly.
In my own sculling I never try to make the hands and seat travel at the same
speed. But I do try to contract my abdominal corset and orchestrate my
various muscle groups so that they work together. I just produce more useful
power when I do. And usually when I am successful I find that during the
drive the hands and seat travel at the same speed until the knees are almost
down.
Cordially,
Charles
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