Help with The Physics of Rowing by Chris Pulman
mushado
I need to know boat speed during the recovery phase and I thought of
deriving it from equation (3) in The Physics of Rowing by Chris
Pulman. My question is about equation (1) in the same document. How
does it fit in the picture?
Help would be very much appreciated
Tinus
Equation 1, momentum conservation, is what you get when you integrate
equation 3, equation of motion, and take R(t) equal to zero.
Carl Douglas
Shame he has to go & include this wording:
".. when the oars are not in the water and the rowers move towards the
stern of the boat, momentum conservation (equation 1) requires that the
boat surges forwards. This motion is clearly visible when viewing a
rowing boat."
Pullman makes an unstated assumption that the rate of the rower's
initial contraction of feet towards his CofG generates a larger forward
force on the boat than the forces of fluid drag. This is neither a good
idea, nor is it necessarily normal.
Cheers -
Carl
--
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Walter Martindale
> On 13/09/2010 12:27, Tinus wrote:
>
> > On Sep 13, 6:16 am, mushado<mush...@gmail.com> wrote:
> >> Hello,
> >> I need to know boat speed during the recovery phase and I thought of
> >> deriving it from equation (3) in The Physics of Rowing by Chris
> >> Pulman. My question is about equation (1) in the same document. How
> >> does it fit in the picture?
>
> >> Help would be very much appreciated
>
> > Equation 1, momentum conservation, is what you get when you integrate
> > equation 3, equation of motion, and take R(t) equal to zero.
>
> Shame he has to go & include this wording:
> ".. when the oars are not in the water and the rowers move towards the
> stern of the boat, momentum conservation (equation 1) requires that the
> boat surges forwards. This motion is clearly visible when viewing a
> rowing boat."
>
> Pullman makes an unstated assumption that the rate of the rower's
> initial contraction of feet towards his CofG generates a larger forward
> force on the boat than the forces of fluid drag. This is neither a good
> idea, nor is it necessarily normal.
>
> Cheers -
> Carl
Um... But... The forces applied to the boat at the foot stretcher
during the recovery _have to be_ greater than the drag or the boat
wouldn't get past the crew in preparation for the next catch, would
it?
Richard Smith (Sydney, AUS) has in the past sent me a plot from his
data collection showing about 100N force towards the bow at the foot
stretcher during the recovery in a single. I'm not sure what the boat
speed was but unless I'm really thick, a force greater than the sum of
all the drags has to be applied to the foot-stretcher, or the boat
just sits there being dragged along by the athlete while fluid drag,
form drag, all the rest of the drags eventually transfer all of the
momentum of the boat/rower/blades into the surrounding water, and the
boat comes to a stop - no? It's not like the boat sits there while
the crew goes towards the stern, and it's not like the rower sits
there while recovering the boat - it's all in motion (assuming that
there's more strokes to be taken).
W
Carl Douglas
> On Sep 13, 5:30 am, Carl Douglas<c...@carldouglas.co.uk> wrote:
>> On 13/09/2010 12:27, Tinus wrote:
>>
>>> On Sep 13, 6:16 am, mushado<mush...@gmail.com> wrote:
>>>> Hello,
>>>> I need to know boat speed during the recovery phase and I thought of
>>>> deriving it from equation (3) in The Physics of Rowing by Chris
>>>> Pulman. My question is about equation (1) in the same document. How
>>>> does it fit in the picture?
>>
>>>> Help would be very much appreciated
>>
>>> Equation 1, momentum conservation, is what you get when you integrate
>>> equation 3, equation of motion, and take R(t) equal to zero.
>>
Understandable, but a slight misunderstanding, Walter.
If you pull with the notionally required 100N (~10kgf) or whatever
matches the fluid drag on the boat, you will exactly prevent the slowing
of the boat. You will also, in that unique situation, be applying a
deceleration to your CofG which will be consistent with the effect of
that 100N on your body mass. So if you weigh 80kg, your own velocity
towards the finish line will be reduced by 100/80 m/sec^2.
Supposing that situation could be sustained, then the boat would keep
moving at whatever was your combined speed at the instant before you
began your recovery while you will appear (to the boat) to be
accelerating towards the stretcher at 1.25 m/sec^2.
I hope that clarifies?
Walter Martindale
proportion to the pull required to accelerate the hull - Once the
blades are out, the system decelerates, but you still have to get the
boat "ahead" to take the catch.
http://www.rowingnz.com/Resource.aspx?ID=56
has velocities from a real sculler.. Graphics aren't that
sophisticated and there's some artifact left over from the data
collection method but they do show the interaction of the boat and the
sculler to produce the system velocity. The acceleration of the boat
in the recovery comes from that (approx) 100N on the foot
stretcher... Note that the sculler's centre of mass still goes in the
positive direction at no slower than about 3.5 m/s - so (as we all
know) the sculler isn't going sternwards in the boat, the boat is
going forward under the sculler...
But you know all that.
W
Tinus
> Note that the sculler's centre of mass still goes in the
> positive direction at no slower than about 3.5 m/s - so (as we all
> know) the sculler isn't going sternwards in the boat, the boat is
> going forward under the sculler...
> But you know all that.
> W
But, during the recovery until just before the catch, the change in
speed of the rower is higher than the change in speed of the boat.
Walter Martindale
Did you look at the graph in the article to which I referred? I get
peak velocity of the boat during the recovery of approx 5.5 m/s, and
at the catch of about 3.7 m/s, or a change in velocity of about 1.8 m/
s (with the boat slowing considerably during the last bit of the
recovery and continuing to slow until shortly after the blade contact
with the water). The sculler, mid recovery (approx same time as boat
at peak velocity) is going slowest, at about 3.7 m/s, and has
retrieved some of her speed from the boat up to about 4.5 m/s at the
catch (which was defined for the study as the moment of blade contact
with the water - taken from film at about 24 frames/sec.). So the
sculler sped up about 0.8 m/s during the last part of the recovery. I
kinda think this makes a little sense, because she was about 60 kg,
and the boat and blades were about 18 kg (wood stampfli, wood sculls,
1982).. So, the negative change in speed of the boat was a little more
than 2 x the positive change in speed of the rower... The two bodies
are connected at the foot-stretcher during the recovery, with a (not
really) frictionless seat for the boat to slide around under the
rower. There's more connection when the blades are in the water
through the pins' contact with the backs of the oars, causing the boat-
water-rower system to move a bit of water around generally towards the
start line, and the boat and rower generally towards the finish line.
Boats have to move more than rowers - otherwise Sir Isaac Newton
screwed up (large mass acting on small mass)
Walter
Carl Douglas
Remember only that the boat's friction often absorbs as much, or more,
power during the recovery as it does during the stroke, whereas you do a
great deal more work during the stroke than during the recovery. In
this context, although the mass ratio is obviously of great significance
in considering ways to get the best out of your rowing, it is wise to
remember that drag is always sucking energy out of the entire system,
superimposing a decelerating force on your own power surges & momentum
exchanges.
Walter Martindale
Yup, The water is always there, drag is complex, and the faster you
go, the harder it is to go faster.
I suspect that's one of the main reasons it takes not too long to
train a crew to go sub-six (in an eight), but it takes years to get
the tools with which to go 40 seconds faster than that.
Average velocity is higher, peak velocity is higher, minimum velocity
is higher, all "dragging" along with them the non-linear relationship
between speed and drag in a viscous medium...
I wonder if any of us has answered the OP's question?
Walter
Carl Douglas
>> exchanges.
>>
>> Cheers -
>> Carl
>>
>
> Yup, The water is always there, drag is complex, and the faster you
> go, the harder it is to go faster.
While I couldn't possibly disagree with you there, I think my point was
a tad more subtle than that? Just that all that drag distorts the
expected shapes of the acceleration & velocity curves. But who cares
about silly stuff like that ;)
>
> I suspect that's one of the main reasons it takes not too long to
> train a crew to go sub-six (in an eight), but it takes years to get
> the tools with which to go 40 seconds faster than that.
For which you could blame a) the nonlinear relationship between
drag-induced power dissipation & velocity or b) the step change in
difficulty for going from everyone in the boat rowing much the same
(which really does matter) to everyone also rowing in a better way than
the accepted norm. I think we might give a lot more thought to item b,
without which good team work by super-fit rowers is bound to hit a wall.
>
> Average velocity is higher, peak velocity is higher, minimum velocity
> is higher, all "dragging" along with them the non-linear relationship
> between speed and drag in a viscous medium...
I think that, rather that distances of victory, maybe we should consider
crews being awarded power points. So, if you go 1% faster (say 20
metres in 2k), you get a 3-point result on the grounds that to go 1%
faster demands an effective power output, or real performance, that's
1.01^3 times greater (=3% higher) than your opponents. That won't
happen, of course, but it's a reminder of how very much more effective
you do need to be to get only small improvements in speed.
>
> I wonder if any of us has answered the OP's question?
Didn't Tinus do that? Anyway, who said we had to stay on-topic? ;)
>
> Walter
Tinus
We are looking at the same graph and I agree with your demonstration
about the acceleration of the boat being larger than the acceleration
of the rower (boat relative to the earth reference frame) when making
the observation around the catch.
However when you do the same numbers at the release you arrive at the
conclusion that, during the initial part of the recovery, it is mainly
the rower who gets accelerated (ignoring the strange bump in the graph
of the boat). Change of velocity for boat is 5.5-5.0=0.5 and for the
rower it is 3.7-5.0=1.3 meters per second.
It is required that the boat is moving more than the rower. However
this can either be done by making the boat move faster or by making
the rower move slower. The situation is the latter and Pulman's words
"momentum conservation (equation 1) requires that the boat surges
forwards. This motion is clearly visible when viewing a rowing boat."
are not correct. Equation 1 is false because it takes R(t) equal to
zero and when viewing a rowing boat we do not see the surge forwards
(the .5 m/s seconds in my calculations) but instead a brake backwards
(the 1.8 m/s in your calculations).
Tinus
We are looking at the same graph and I agree with your demonstration
about the acceleration of the boat being larger than the acceleration
of the rower (boat relative to the earth reference frame) when making
the observation around the catch.
However when you do the same numbers at the release you arrive at the
conclusion that, during the initial part of the recovery, it is mainly
the rower who gets accelerated (ignoring the strange bump in the graph
of the boat). Change of velocity for boat is 5.5-5.0=0.5 and for the
rower it is 3.7-5.0=1.3 meters per second.
It is required that the boat is moving more than the rower. However
this can either be done by making the boat move faster or by making
the rower move slower. The situation is the latter and Pulman's words
"momentum conservation (equation 1) requires that the boat surges
forwards. This motion is clearly visible when viewing a rowing boat."
Walter Martindale
I'm confused... At (or very near release) the boat and rower are going
the same speed. The moment the rower moves any part of his/her body
towards the stern, the action-reaction law means that the boat is
moved towards the bow in proportion to the amount of mass being moved
(with some accounting for the drag from the water)... e.g., hands slow
down (start moving toward the stern) boat speeds up. I don't know for
sure, but I half suspect that the dip in boat velocity might relate to
the timing of the athlete moving from "finish position" to the point
where she started moving her legs, but I can't be sure because the
film is long gone, and any stick figures I could generate from the
original data are pretty noisy before data filtering. If it's not an
artifact of the rowing style, it's an artifact from data collection,
but without funding and a lot of equipment I'm not going to start
again...
W
mruscoe
> We are looking at the same graph and I agree with your demonstration
> about the acceleration of the boat being larger than the acceleration
> of the rower (boat relative to the earth reference frame) when making
> the observation around the catch.
> However when you do the same numbers at the release you arrive at the
> conclusion that, during the initial part of the recovery, it is mainly
> the rower who gets accelerated (ignoring the strange bump in the graph
> of the boat). Change of velocity for boat is 5.5-5.0=0.5 and for the
> rower it is 3.7-5.0=1.3 meters per second.
>
> It is required that the boat is moving more than the rower. However
> this can either be done by making the boat move faster or by making
> the rower move slower. The situation is the latter and Pulman's words
> "momentum conservation (equation 1) requires that the boat surges
> forwards. This motion is clearly visible when viewing a rowing boat."
> are not correct. Equation 1 is false because it takes R(t) equal to
> zero and when viewing a rowing boat we do not see the surge forwards
> (the .5 m/s seconds in my calculations) but instead a brake backwards
> (the 1.8 m/s in your calculations).
I think it makes more sense if you look at the changes of speed of the
sculler and boat in relation to the total system speed.
It is all complicated by the fact the sculler is a jointed body and
various segments move by different amounts at different speeds. For
example, for the first part of the recovery, the legs could almost be
counted as part of the boat weight, while the arms and trunk move in
relation to the boat, and then when the legs start to move the upper leg
is moving at twice the speed of the lower leg in relation to the boat,
and both those segments are probably moving slower than the trunk is (in
relation to the boat) for some parts of the slide.
Walter Martindale
I'll see if I can find the data and plot segment velocities...
Tinus
> I'm confused... At (or very near release) the boat and rower are going
> the same speed. The moment the rower moves any part of his/her body
> towards the stern, the action-reaction law means that the boat is
> moved towards the bow in proportion to the amount of mass being moved
> (with some accounting for the drag from the water)
If only the system would be isolated. The boat experiences two forces
(water and rower) in opposite direction. So, you are not realy
accounting for the drag from the water if you say the movement of the
boat is determined solely by the movement of the rower.
Tinus
> It is all complicated by the fact the sculler is a jointed body and
> various segments move by different amounts at different speeds. For
> example, for the first part of the recovery, the legs could almost be
> counted as part of the boat weight, while the arms and trunk move in
> relation to the boat, and then when the legs start to move the upper leg
> is moving at twice the speed of the lower leg in relation to the boat,
> and both those segments are probably moving slower than the trunk is (in
> relation to the boat) for some parts of the slide.
One could still use a two body model (rower/crew and boat) because the
momentum conservation equation is linear in mass and velocity. Moving
the 8kg arms at 3.0m/s is equivalent to moving the 80kg body at 0.3m/
s. However, the energy conservation equation would be flawed.
Carl Douglas
With work being done to accelerate the arms, energy is not locally
conserved.
Excessive vigour in pushing the arms away, & similar over-enthusiasm in
"getting weight out of the bows", serve only to add a bump to the boat's
speed profile after the finish which is then a costly & irrecoverable
imposition upon the overall drag penalty.
Funny how irrational beliefs, widely held but never subjected to
analytical examination, bring counter-productive outcomes which impair
the performances of large numbers of rowers.
Carl Douglas
It's such a pain when crude reality intrudes on simple models ;)
Try this simple(r) model of reality, for the finish & recovery only.
This model takes as its basis a constant-velocity reference frame,
supposedly moving at boat mean speed but in reality not moving at all:
1. A rower sits on a sliding seat in a real boat with all usual gear
(blades, etc.).
2. The boat sits on a low-friction, horizontal track of sufficient
length that the boat won't fall off the ends when it moves during the
exercise.
3. The boat is connected sternwards by a spring (e.g. a bungee cord) to
a fixed point - i.e. the spring tends to pull the boat sternwards.
4. Size this spring such that its tension will vary from about 100N when
the boat is held at the notional finish position to an appropriately
lesser figure (= 100 x (Vcatch/Vfinish)^3) when the boat reaches
whatever becomes its position on the track at wherever the crash-test
dummy rower goes to take the catch (pick positions from the existing
wealth of telemetry data, or determine bungee cord length by trial & error).
Now set the rower into the finish position. Draw the boat along the
track until spring tension = 100N. Hold the boat at that point with a
hook acting on a hair trigger. Let the rower's first act of recovery
(hand, head or body movement) immediately trigger the release of the
retaining hook.
Measure everything that happens - & pick up the pieces at the end.
One last request: please don't do this with one of our products.
Although it'll take the punishment better than the rest, I'd prefer you
to use something you don't mind damaging. :)
Better still, you can compute the results for such a simple model, &
incorporate simple refinements such as a velocity, not position,
dependent &, non-linear drag function. however, folk being the way they
increasingly are, simple experiments seem to carry ever less weight than
heavily instrumented attempts to monitor every aspect of a real-life
action with data streams which then defy analysis but produce pages of
maths & look wonderful in research papers. Bullshit baffles brains!
zeke_hoskin
That one is really easy to measure.
Put a liter or two of water in the boat. Row. Observe.
When you drive hardest, the water surges back, indicating that the
boat is accelerating.
During the recovery, if you pull in hard with your feet, you can still
accelerate the boat forward,
and observe the water in the boat surging into the stern. This is
wasteful.
Generally you will see the water slopping slightly forward, indicating
that the boat is slowing
slightly (but still going faster than you are, so you move into the
stern w.r.t the boat and prepare
for the next stroke.)
Since it's not humanly possible to apply a lot of oar drive before you
have reversed your body's
motion into the stern, you will observe a pronounced sloppage forward
immediately before the catch and until
you get a good drive going.
I'd hazard a guess that part of efficient technique is minimizing the
amount and duration of this slowdown.
Possibly the model will give you figures. Certainly an accelerometer
on the boat will give you better
numbers. The water in the boat gives you a cheap rough check (and if
you row the way I do,
an unavoidable one.)
Carl Douglas
> On Sep 14, 11:08 am, Walter Martindale<wmart...@gmail.com> wrote:
>> On Sep 13, 5:30 am, Carl Douglas<c...@carldouglas.co.uk> wrote:
>>
>>
>>
>>> On 13/09/2010 12:27, Tinus wrote:
>>
>>>> On Sep 13, 6:16 am, mushado<mush...@gmail.com> wrote:
>>>>> Hello,
>>>>> I need to know boat speed during the recovery phase and I thought of
>>>>> deriving it from equation (3) in The Physics of Rowing by Chris
>>>>> Pulman. My question is about equation (1) in the same document. How
>>>>> does it fit in the picture?
>>
>>>>> Help would be very much appreciated
>>
>>>> Equation 1, momentum conservation, is what you get when you integrate
>>>> equation 3, equation of motion, and take R(t) equal to zero.
>>
Good stuff, Zeke. May I add a couple of points?
It is easier for the sculler to have a reduced check at the catch than
the sweeper, because the sculler, working along the stem of the capital
letter Y, with their arms as its 2 symmetrically diverging limbs, really
can get their blades loaded & bent before there need be much (or any?)
load onto the stretcher (the sculler's Y is more open than the typed
letter Y).
And what matters in the check at the catch, purely in its effect on mean
speed & time averaged hull frictional drag, is not the intensity of the
check but the area it occupies in the time vs velocity plot. of course,
the check also results in a bounce or a pitching motion of the boat,
which may muck up the flow around the boat & more certainly generates
energy absorbing wave patterns.
Charles Carroll
>amount and duration of this slowdown.
Zeke,
By "minmimizing the amount and duration of this slowdown" do you mean
the amount of negative peak velocity and the duration of deceleration?
If so, then take a look at RBN February 2004.
1) The first crew is the faster crew.
2) The first crew increases force at the catch much more quickly than
the second crew but has relatively lower maximal and average force
application.
3) The boat speed and acceleration curves of the first crew have
deeper negative peak at the catch but a much quicker increase
afterwards.
To me this suggests that while the faster crew increases the amount of
slowdown at the catch, it also shortens the duration of this slowdown.
Am I wrong to think that the key here seems to be not the amount of
check at the catch, but the quickness of reversing deceleration? Look
at the Graph for Boat Acceleration. The faster crew is much quicker at
reversing deceleration - that is, re-accelerating the boat - that the
slower crew.
Cordially,
Charles
Carl Douglas
I think I've already said it, Charles, something like this:
You need to minimise the area within the time/velocity curve that
represents this check = length (time) x depth (velocity reduction) - not
just its depth.
But it is not useful to have a reduced velocity drop if the price paid
is that the catch is consequently much delayed.
Charles Carroll
> is that the catch is consequently much delayed.
Carl,
Yes, that is the point I am trying to make - i.e. it is useless to
reduce boat check if it delays force application at the beginning of
the drive.
In theory, of course, you want to reduce as much as possible both
negative peak velocity and the duration of deceleration.
But what about in practice? Is this possible?
As you once wrote, "Everything in rowing is a compromise." It comes
with a price. It is giving away something in order to gain something
else.
Valery Kleshnev's data and observations of my own sculling lead me to
think that it is all right, even desirable, to have more boat check if
it results in quickening force application in the initial phases of
the drive.
As I wrote, what signifies is not the amount of check at the catch,
but the quickness of reversing deceleration.
Lately, as I begin the drive, I find myself visualizing a game of
billiards. My legs and arms function as a kind of cue stick, striking
against the stretcher and oar handles with the hope of passing on
kinetic energy to the boat and reversing its deceleration. The more
quickly I accomplish this, the more quickly I accelerate the boat to
compensate for the velocity lost in deceleration, the faster the boat
goes.
Fairbairn writes about tap/tap/taping the boat along. I wonder if I am
beginning to understand what it is finally all about.
Probably not! But it is not going to prevent me from trying.
Cordially,
Charles
Zbigniew A.
> Put a liter or two of water in the boat. Row. Observe.
[...]
>
> I'd hazard a guess that part of efficient technique is minimizing the
> amount and duration of this slowdown.
> Possibly the model will give you figures. Certainly an accelerometer
> on the boat will give you better
> numbers. The water in the boat gives you a cheap rough check (and if
> you row the way I do,
> an unavoidable one.)
I already wrote a reply to the thread "Re: Devices for measuring boat
check", that was a long time ago, but I couldn't sent it off. This thread is
related, in a way.
In April this year I had a pleasure to attend a talk by Dr. Valery Kleshnev
at "Olympiatoppen" in Oslo. Who Dr. Kleshnev is, I don't have to repeat.
But can't resist priding myself that 30 years ago I was competing with him
directly; we were both in our national squads in 4x (of USSR and POL) and we
were competing against each other in 1980 and 1981.
In his talk Dr. Kleshnev showed how focusing on "managing a boat run" and on
reducing the boat check might be a "dead end street".
Rowing hard, with power, unavoidably causes the boat to accelerate. Pushing
the footstretcher with ones legs, applying power to the oars, all this cause
an abrupt change in boat's speed -- the harder you push, the bigger a
change.
Overly focusing on minimizing the losses, on a smooth ride, may lead to
ineffective propulsion.
The main point of Dr. Kleshnev's talk was that it is probably the best not
to pay attention to the boat check at all. "Forget about it." Instead, we
should focus on most effective application of *power*, on moving the system
forward.
Yours Virtually, Zibi
Walter Martindale
I'd agree, with the proviso - focus on most effective application of
power to move the system forward with as little check as possible. A
loss of velocity is a loss of velocity, just as a spike of velocity
(and drag) is a spike in velocity - you want to keep the checks and
the peaks as brief as possible...
W
Charles Carroll
> is that the catch is consequently much delayed.
Zibi,
Every coach I have ever taken a lesson from and almost everything I
have ever read about sculling has encouraged me to think that boat
check is a fault.
I cannot count the times I have heard that any check at the catch
beyond the absolute minimal is indication that I am not as smooth and
relaxed as I could be. It means that I am moving a boat much slower
than I could. In short, boat check is evidence of poor timing and bad
blade work.
But Valery Kleshnev's data from RBN February 2004 suggests
differently. While the faster crew has quicker force increase in the
beginning phases of the drive, it also has increased boat check.
So how should we interpret his data?
To me the data suggest that when it comes to producing a faster crew
quicker force increase is more important than increased boat check. If
I am right about this, then have we overemphasized the importance of
boat check? Shouldn't we instead concentrate on teaching ourselves how
to quicken force increase?
And the last question, perhaps the most important, is whether
increased boat check is inevitable with quicker force increase?
Zibi, it's good to have you back.
Cordially,
Charles
Carl Douglas
>> It is not useful to have a reduced velocity drop if the price paid
>> is that the catch is consequently much delayed.
>
> Zibi,
>
> Every coach I have ever taken a lesson from and almost everything I
> have ever read about sculling has encouraged me to think that boat
> check is a fault.
>
> I cannot count the times I have heard that any check at the catch
> beyond the absolute minimal is indication that I am not as smooth and
> relaxed as I could be. It means that I am moving a boat much slower
> than I could. In short, boat check is evidence of poor timing and bad
> blade work.
>
> But Valery Kleshnev's data from RBN February 2004 suggests
> differently. While the faster crew has quicker force increase in the
> beginning phases of the drive, it also has increased boat check.
>
> So how should we interpret his data?
That, while it could perhaps have been even better, at that time they
were doing the complete package well enough.
What is more significant to me, as you say below, is the quicker force
rise - which of course is the antithesis of the notions some have about
letting the blade "lock into the water" before applying the load.
>
> To me the data suggest that when it comes to producing a faster crew
> quicker force increase is more important than increased boat check. If
> I am right about this, then have we overemphasized the importance of
> boat check? Shouldn't we instead concentrate on teaching ourselves how
> to quicken force increase?
The well performed exercise does not allow concentration on one element
to the exclusion &/or detriment of all others. The best solution
optimises the mix of variables. Lack of time may well oblige a
thoughtful coach to focus on the most easily attainable improvements.
Only an unthinking coach will dismiss all other ways (if time permits)
to further enhance performance.
>
> And the last question, perhaps the most important, is whether
> increased boat check is inevitable with quicker force increase?
Until & unless we actively explore this topic, rather than make
unfounded claims one way or t'other, we will never know.
Rowing is a very strenuous activity performed by athletes with, IMHO, a
rather limited set of skills but lots of guts. When asked to do
something a bit more skilfully, the average rower tends to duck the
challenge & defend what they're already doing as good enough as long as
they can pull even harder.
Real finesse, in rowing, is seen as a stylistic issue, not as a matter
of important substance. We could learn quite a bit from those other
athletic pursuits, from dancing to ice-dancing to pole-vaulting, as well
as from the playing of musical instruments, in which particular skills
have to be honed to extremely high levels - levels which a novice would
at first consider unattainable. But we first have to analyse & better
define what we need to do, why & then how.
>
> Zibi, it's good to have you back.
True!
>
> Cordially,
>
> Charles
Zbigniew A.
>
> I'd agree, with the proviso - focus on most effective application of
> power to move the system forward with as little check as possible. A
> loss of velocity is a loss of velocity, just as a spike of velocity
> (and drag) is a spike in velocity - you want to keep the checks and
> the peaks as brief as possible...
Of course, Walter you are absolutely right. However... :-)
The issue of the boat check surfaced several times during Valery Kleshnev's
talk. At the end, in a crossfire of Q & A, he said something like this:
What we are talking here is fine nuances of rowing technique and we assume
that elite rowers, who row/scull thousands of kilometers per year have all
major issues sorted out. We can probably assume they are not doing something
that would cause significant boat check, (like shooting the seat, comes to
my mind). Therefore Valery postulates to leave the question of a boat run
alone. Cause it could easily sidetrack us from the more important thing,
which is most effective propulsion. Focusing on a boat check can easily lead
to less effective drive. We can not reduce the boat check by much, if at
all, while we can lose much more in wasted/misused energy of the drive. We
don't want to throw the baby with the bath, do we?
I don't remember Valery to state that more effective propulsion would be
necessary associated with more boat check. But he said that the faster we
row, the more drag, the more power we have to put into rowing, the higher
the cadence -- therefore the more "dirty" it may look.
Such was a practical conclusion from his talk. The theory behind it i will
lay out in my reply to Charles, but that only after todays training, OK? :-)
Virtually, Zibi
Walter Martindale
True. I've been on the shoreline at Lake Karapiro (and running a
video camera) when Rob Waddell and Mahe Drysdale have been bashing it
out against each other.
A number of people criticize the way these very large men bounce the
boat around during their racing, but... Hang on - each has been the
world's fastest in a single - Rob in 99, Mahe in 06 or 07... Both of
them move relatively large masses to and fro about the centre of mass
of the boat, while moving the whole thing towards the finish line.
Both of them apply huge (in human rower terms) forces to the foot
stretcher and handles - of course the boat is going to bounce around a
bit. The point is that they manage the timing and direction of these
forces so that what disruption in the run of the boat they do generate
is as small as they can get it - if they didn't manage these factors,
theie boats would go more slowly.
W
ATP
"Walter Martindale" <wmar...@gmail.com> wrote in message
news:594121e7-183d-43d8...@i17g2000vbq.googlegroups.com...
theie boats would go more slowly. (Walter)
***********
Well put. Propelling the boat as quickly as possible may not be compatible
with some sort of imagined aesthetic ideal of grace and finesse. (Mike ATP)
OE attribution is suddenly broken...
Charles Carroll
>element
> to the exclusion &/or detriment of all others.
Carl,
It has taken me six years to understand the importance of the "correct
balance of all components of rowing technique."
The other day when I came in off the water I wrote a little meditation
on this subject. At first I was going to post it on r.s.r. Then I
thought better of it. I thought that people must be sick of my "little
meditations." So I decided just to leave it in my notes. But I'll post
it now because it is is so apropos.
Since Volker Nolte's piece on Michelle Guerette in the April 2009
issue of the Rowing News, I have focused on increasing the angle of
the oars at the catch. I decreased the spread, shortened the inboard,
and moved the rails sternwards. And when I was on the water I did
everything I could to get as long as I could. I practiced staying on
the frontstops and balancing at the stern until it became second
nature. I practiced spreading my arms wider apart. I practiced holding
the oar handles at their tips.
And what was the result? The harder I practiced - the more I revised
my rigging - the longer I gotr - the slower I became.
In my obsession with getting longer at the catch I had ignored a
simple truth - namely, that sculling technique consists of many
different elements. For a technique to be balanced all of its elements
must be correctly adjusted to each other. Imbalance is when one
element is out of proportion to the others. Why was it that the harder
I practiced the slower I became? It was because my obsession with
getting long at the catch made me blind to the other elements of the
stroke. Instead of helping me to scull faster, it produced an
imbalance in my technique that was guaranteed to slow me down.
On this subject Valery Kleshnev has a simple paragraph that seems to
me should be taken to heart by any rower or sculler interested in
technique:
"Trying to improve one thing, a coach could exaggerate or affect
negatively other components of technique; e.g. in trying to improve
the leg drive, "bum shoving" could be developed; in trying to produce
more power with the trunk, one could make the finish of the drive
inefficient, etc. Examples are endless. Biomechanics can provide you
with objective information and find a correct balance of all
components of rowing technique." (RBN August 2009)
The goal - and this ought to have been my goal all along - is to find
the correct balance of all elements in rowing technique.
Cordially,
Charles
Charles Carroll
> video camera) when Rob Waddell and Mahe Drysdale have been bashing
> it
> out against each other.
>
> A number of people criticize the way these very large men bounce the
> boat around during their racing, but... Hang on - each has been the
> world's fastest in a single - Rob in 99, Mahe in 06 or 07... Both of
> them move relatively large masses to and fro about the centre of
> mass
> of the boat, while moving the whole thing towards the finish line.
> Both of them apply huge (in human rower terms) forces to the foot
> stretcher and handles - of course the boat is going to bounce around
> a
> bit. The point is that they manage the timing and direction of these
> forces so that what disruption in the run of the boat they do
> generate
> is as small as they can get it - if they didn't manage these
> factors,
Walter,
Very well said! Who could disagree with Mike?
This also happens to be particularly encouraging to me. I have been
training at higher stroke rates (racing rates) and this has affected
“the prettiness” of my stroke. I have been missing water and producing
a little more turbulence at the catch. I have not been getting as long
as I used to. And I am not as smooth as I once was.
One very close friend even told me that it looks like I no longer care
about technique. Nothing could be further from the truth.
Sometimes it seems to me that my only ally is my stopwatch.
Cordially,
Charles
Charles Carroll
> would be
> necessary associated with more boat check. But he said that the
> faster we
> row, the more drag, the more power we have to put into rowing, the
> higher
> the cadence -- therefore the more "dirty" it may look.
>
That “Socrates of the towpath” otherwise known to us as Steve
Fairbairn used to preach “no showy movements.” You can find this idea
throughout all his writings.
Fairbairn’s crews were frequently criticized for how they looked when
they rowed. But they won.
The question I ask myself these days is would I rather look pretty or
would I rather row faster?
Cordially,
Charles
Zbigniew A.
>
> Every coach I have ever taken a lesson from and almost everything I
> have ever read about sculling has encouraged me to think that boat
> check is a fault.
>
> differently. While the faster crew has quicker force increase in the
> beginning phases of the drive, it also has increased boat check.
>
> So how should we interpret his data?
Let me begin with some theory I learned from a talk by Dr. Valery Kleshnev
at "Olympiatoppen" in Oslo. It was half a year ago, I didn't take any notes
and my brain is an old fossil, so take it as a rough description:
First Dr. Kleshnev described different losses during the rowing race. About
80% are "internal losses" which means "inside the rowers body". I am yet to
figure out what it means... About 20% are losses in a boat, which can be
further divided into several components.
Only about 2% or 1,3%, not sure now, are losses caused by uneven run (speed)
of the boat. And according to laws of physics, due to a cyclic nature of
rowing, they can not be eliminated entirely. How much of this percent or two
we can save? As Kleshnev suggests later on, it is not worth bothering.
Some 6% or 8% are losses of blade work. And here Dr. Kleshnev advices us to
look for improvements. Still, not too hard, cause looking for minimizing the
losses in his view is the wrong way of looking at rowing.
This expression I remember well, cause it was repeated several times:
*** "Instead of improving the efficiency of rowing, which means minimizing
the losses, we should focus of improving the efficiency of propulsion." ***
Managing the smooth boat run can easily lead to less effective drive, what
Dr, Kleshnev illustrated with numerous examples, pictures and graphs.
Now, how to improve the effectiveness of a drive? How to move the boat
faster to the finish line?
We need to learn how to look at the whole system.
Remember when you discovered that we are not shuffling the water with our
oars, that we are moving the boat while blades stay in (almost) same place?
How an eye opener it was?
Or the mind blowing illumination that it is not the rower moving back and
forth over the boat, that it is the boat moving under the rower?
Another (third) eye opener i learned from the talk of Dr. Kleshnev:
"Focusing on moving the boat is not the most effective way of rowing. More
effective is focusing on a rower, on moving his body itself. We shall move
the rowers body (relatively heavy object) towards the finish line, as fact
and as effectively as we can, and the (much lighter) boat will follow."
Then Dr Kleshnev presented many examples, pictures and graphs, of the four
classic rowing styles and estimated their effectiveness.
Now, somebody help me... so called Adam style, DDR style, Rosenberg style...
and the fourth?
> To me the data suggest that when it comes to producing a faster crew
> quicker force increase is more important than increased boat check.
That typo, you meant reducing the boat check, right?
Yes, quicker force increase, yes of course!
But what is probably more important, where do you apply this force: to the
boat or... to yourself? When you enter the blades and try to start to
accelerate as quickly as possibly, what do you try to move, the boat?
The rower/crew's weight is many times more than the weight of the equipment.
So any inefficiency in this department may cost us much more. This is where
we should look for improvements!
And if we manage to move the rower faster to the finish line, the boat will
follow. This process is perfectly described in Walter Martindale's paper
"Control of momentum. View from a boat's perspective."
Walter, can you provide the direct link?
> If
> I am right about this, then have we overemphasized the importance of
> boat check? Shouldn't we instead concentrate on teaching ourselves how
> to quicken force increase?
Yes. Dr. Kleshnev said in the opening of his talk that the boat check, and
"managing the boat run" are generally overemphasized. He advises us to leave
the question of the boat check alone.
As i described in detail in the reply to Walter.
> I cannot count the times I have heard that any check at the catch
> beyond the absolute minimal is indication that I am not as smooth and
> relaxed as I could be. It means that I am moving a boat much slower
> than I could.
Again, Valery explained, that focusing on a smoothness may become easily a
"dead end". We need to row stronger, harder, faster! If it is to look
brutal*, let be it!
_________________________________
*) he didn't use the word "brutal". it is my interpretation.
> And the last question, perhaps the most important, is whether
> increased boat check is inevitable with quicker force increase?
>
Now, let me try to answer your question, Charles:
If we focus on moving the rower, not the boat, especially at the catch, it
may happen the the boat will be.. kind of...left behind? Initially at least.
So when we measure the boat check around the catch, it may increase, right?
We are talking very fine details of course...
It may look ugly, but if it moves faster this way...
I don't remember Dr. Kleshnev to say directly, that more effective
propulsion (drive) have to be associated with more boat check, but from his
talk we may draw such a conclusion. As far as I understand.
If we analyze the speed of the hull moving through the water, around the
moment of a catch it is a slowest. With the catch, we try to apply our force
as quickly as possibly to move forward... But, to move what?
If we focus on moving the boat, then actually the boat accelerates earlier
thus the boat check is minimized. If we focus on moving the rower, though...
This is what i remember from the talk of Dr, Valery Kleshnev. And this is
not a verbatim record of his words; rather how i digested and remembered it.
All mistakes and errors are mine -- if something does not make sense, blame
it on my, on my bad memory!
> Zibi, it's good to have you back.
Oh, I never left! I just couldn't post to r.s.r, that's it; but i would read
it religiously every day. :-))
Yours Virtually, Zibi
Zbigniew A.
> This expression I remember well, cause it was repeated several times:
> *** "Instead of improving the efficiency of rowing, which means minimizing
> the losses, we should focus of improving the efficiency of propulsion."
> ***
Oh, I spoiled this one! Excuse me...
It ought be:
"Instead of improving the efficiency of rowing, which means minimizing
the losses, we should focus of improving the *effectiveness* of propulsion."
Effectiveness is a key word.
--
Yours Virtually, Zibi
Charles Carroll
> minimizing
> the losses, we should focus of improving the *effectiveness* of
> propulsion."
> Effectiveness is a key word.
Zibi,
And trying to minimize "boat check" while ignoring "quickness of force
increase in the beginning phases of the drive" is a perfect example.
Did I say we missed your voice in these discussions? Oh, my friend,
how we have missed your voice!
Warmest regards,
Charles
Carl Douglas
Zibi -
Please forgive me, but I am completely unaware of there being any
meaningful difference between the terms 'efficiency' & 'effectiveness'.
Efficiency is the ratio of the useful work done to the total work done.
Effectiveness is a looser term but means, I think, getting a bigger bang
for your buck. Which appears to mean the same, unless the effective
sculler has some magic way of extracting a higher efficiency from what
he does than the efficient sculler. In which case, that just makes him
a more efficient sculler than the other efficient sculler
There is no hidden store of input work available beyond the 100% mark
available to your 2 scullers, so their individual efficiencies are
always below 100% - & by quite a margin too, in all of us.
Now how does the effective sculler differ from the efficient sculler, if
at all - unless you are proposing that being efficient hampers your
performance while being a bit cruder does not.
I think you need to better quantify all those little bits which it seems
to me you propose to forget about. If a small aspect of technique is
potentially worth 6% of your total effective propulsive work (i.e. of
your propulsive efficiency), then improving that from say 3% to 4% is
going to give you more than 1% increase in propulsive effect, or 0.33%
on speed, or 6.6m over 2K. I don't think that can be so unimportant, do
you?
The problem is that rowers want to know "what matters". And rowers who,
like you, have rowed at a very high level do wish to believe that they
could have done nothing better when at the top of their performance.
However, I would respectfully suggest that each of us makes a
semiconscious but possibly irrational decision to forget about niggling
bits of technique - 'cos we feel it more important to train harder, or
to focus on something else. And that does not make us right.
Rowing over its Century & a half has been full of sweeping but erroneous
assumptions, from diet to technique to training, which have certainly
held back current & far future performances. If rowing is not to
degenerate simply into a grinding beefsteak challenge (with all the
fancy pharmacology that may bring in under the counter), then it is
surely worth exploring more carefully how to do it better. Which may
mean turfing out any number of fondly-held mantras & fictitious beliefs.
It won't be done by just dismissing elements of the stroke as
unimportant, even when those dismissals are based on your recall of what
one of the great explorers of technique may have said a few years back.
It may be all too simplistic, but fits well with the "My brain aches"
mentality of certain coaches & rowers. What you learn about science,
all science, is that it is not handed down on tablets of stone but it
continually advances. Views which seemed good once get tested, which in
rowing demands test dummies really willing to throw themselves into new
ways of doing the job.
Let's dismiss nothing. Instead, let's explore & learn. Just imagine
rowers made the kind of technical advances made in recent years by
gymnasts... Just suppose rowing really did know something about fluid
dynamics......
ATP
"Carl Douglas" <ca...@carldouglas.co.uk> wrote in message
news:8g4g3s...@mid.individual.net...
> On 24/09/2010 17:54, Zbigniew A. wrote:
>> Zbigniew A. wrote:
>>> This expression I remember well, cause it was repeated several times:
>>> *** "Instead of improving the efficiency of rowing, which means
>>> minimizing
>>> the losses, we should focus of improving the efficiency of propulsion."
>>> ***
>>
>> Oh, I spoiled this one! Excuse me...
>>
>> It ought be:
>>
>> "Instead of improving the efficiency of rowing, which means minimizing
>> the losses, we should focus of improving the *effectiveness* of
>> propulsion."
>>
>> Effectiveness is a key word.
>>
>
> Zibi -
>
> Please forgive me, but I am completely unaware of there being any
> meaningful difference between the terms 'efficiency' & 'effectiveness'.
>
> Efficiency is the ratio of the useful work done to the total work done.
>
> Effectiveness is a looser term but means, I think, getting a bigger bang
> for your buck.
Most definitions refer only to success in achieving a certain result- so you
could be effective without being efficient, or vice versa. You might have a
boiler which is most efficient at 40% of rated capacity- yet incapable of
heating the space to the required temperature unless you run it at a less
efficient 90% capacity. So perhaps he is saying that net propulsion is more
important than efficiency?
Mike
Charles Carroll
In the beginning phases of the drive Crew 1 produces a greater
negative peak velocity than Crew 2.
Crew 1, however, crosses the finish line 10 seconds ahead of crew 2.
Which Crew is the most efficient?
And which Crew is the most effective?
Cordially,
Charles
Richard du P
wrote:
>
> Which Crew is the most efficient?
> And which Crew is the most effective?
In my submission, IF the crews have each set out to cross the line
first, then Crew 1 is the most effective. [that can be a big "IF";
people and teams can have an astonishing variety of goals]
..... and the more efficient crew is the one which can row level with
the other crew with the lesser expenditure of energy - maximising the
output/input ratio AT THAT PACE
[oh dear, this horrid spellchecker doesn't like "maximising" - not
enough zeds? - not enough zees? - probably can't do differential
equations either].
Not sure that the crew with the greater negative peak velocity is
necessarily either, neither or both.
These terms are commonly misapplied, at least they were when I was in
the UK public service - when HM Inspectorate of Constabulary certified
that a police force was "efficient" I think they always meant
"effective"
..... but then the UK is distinguished by being largely run by people
who gave up maths/math with a sigh of relief at age 15.
Richard du P
Richard du P
causes of inefficiency, at least as far as you can do so without
prejudicing the application of useful work, is likely to promote
effectiveness?
Zbigniew A.
> On 24/09/2010 17:54, Zbigniew A. wrote:
>> It ought be:
>>
>> "Instead of improving the efficiency of rowing, which means minimizing
>> the losses, we should focus of improving the *effectiveness* of
>> propulsion."
>>
>> Effectiveness is a key word.
>>
>
> Zibi -
>
> Please forgive me, but I am completely unaware of there being any
> meaningful difference between the terms 'efficiency' & 'effectiveness'.
>
Oh, Carl, no prob. I am only too aware of my bad English.
However, here I tried to repeat what i remember from Valery Kleshnev's talk.
When using the word "efficiency" he many times clarified that he means
minimizing the losses.
I had to look up the dictionary:
Efficiency -- [...] when somebody or something uses energy or time well,
without wasting any. 2. /SPECIALIZED/ the difference between the amount of
energy that is put into a machine in the form of fuel, effort etc. and the
amount that comes out of it in the form of movement.
And Valery several times stressed that he sees efficiency as something
different than effectiveness.
> Effectiveness is a looser term but means, I think, getting a bigger bang
> for your buck.
Carl, I really like your definition, it is better than Webster's!
This is exactly what we are talking here: more bang!
Well, maybe it is not clear enough only from dry definitions of these words,
but it was clear from the context of Valery's talk, from his remarks, and
later in Q & A he clarified this:
He postulates that there are ways of significantly improving the speed of
moving the system boat&rower forward. In his view it is possible to produce
more propulsion -- from the same amount of muscle effort -- by changing our
focus from moving the boat to moving the rower's body toward the finish
line.
Even at the cost of less smooth boat run, which would not increase losses by
much.
Instead of focusing on minimizing the losses of energy by managing the
(smooth) boat run we should rather focus on effectiveness of the drive.
We produce significantly more, perhaps lose part of the surplus, but it
still pays back.
I hope this is clear by now, that we are not talking here about snake oil.
--
Yours Virtually, Zibi
Walter Martindale
> He postulates that there are ways of significantly improving the speed of
> moving the system boat&rower forward. In his view it is possible to produce
> more propulsion -- from the same amount of muscle effort -- by changing our
> focus from moving the boat to moving the rower's body toward the finish
> line.
> Even at the cost of less smooth boat run, which would not increase losses by
> much.
> Instead of focusing on minimizing the losses of energy by managing the
> (smooth) boat run we should rather focus on effectiveness of the drive.
>
> We produce significantly more, perhaps lose part of the surplus, but it
> still pays back.
> Yours Virtually, Zibi
Moving the body toward the finish - only happens when the blades are
well-stuck into the water from the moment of farthest reach, hang onto
them for dear life, and try to break the foot stretcher all the way
til the blades have to be taken out of the water. (I know my grammar
is rolling around in her grave but that's too bad...)
W
Charles Carroll
While it is always dangerous to suppose that you know what someone
else is thinking, I will hazard that I know what is in Carl's mind on
this one.
Carl's perspective is that of an engineer who designs boat hulls for
specific purposes. From that perspective how could the most efficient
hull not also be the most effective?
But are we talking about hull design? Or are we talking about rowing?
The variables in the equation of hull design are complex enough. Now
throw in a rower with a specific skill level, athletic ability and
physical conditioning to supply the motive power and see just how much
more complex these variables become.
Who of us here doesn't know that a novice rower in a novice race can
be much more effective rowing an inefficient hull design? Or that this
same rower might be much more effective rowing a shorter stroke than
trying to row a longer stroke? Who would argue that this rower is
rowing efficiently? But in the same vein, if he wins, would anyone
argue that he is not rowing effectively?
Cordially,
Charles
Ps. Now re your spell checking problems: Don't we on this side of the
pond write most of the spell checkers? And you, as a Brit, know we
spell funny. The wonder is that you would ever let us get away with
this!
Carl Douglas
Let's try to drag us back from the illusory world of 110% performance ;)
Only if you have a higher power output can you go faster while
sacrificing efficiency. If in some way you are able to generate more
power, e.g. as a result of sacrificing some refinement of your stroke,
then a less efficient stroke may make a faster crew.
But then you do have to work harder. Is there an easier way to generate
more work than when following some as-yet imagined "most efficient way
to row"? Well maybe but, until proven, it's just a fun discussion over
a beer or 3.
If you are truly working at your physical maximum, then the most
efficient technique will be your most effective. Otherwise we're in
Looking Glass land with Lewis Carroll's Humpty Dumpty, who opined that a
word could mean whatever he chose it to mean. There is no way that the
most effective, at fixed power output, can be better than the most
efficient.
A bigger bang for the buck is in no way different, except in its more
emotive language, than an improvement in efficiency. That invested
buck, your work output, remains the same. What actually propels the
boat is not emotion, just your power output multiplied by the efficiency
of your stroke. And, since efficiency is always less than 100%, the
rest of your power output has gone into messing up the water around the
blade.
What we seem to be discussing are excuses for deciding which aspects of
scientifically sound technique to ditch in pursuit of greater speed. I
think that is not rational. And I've seen scullers, when rattled by
being down during a race, throw technique overboard in the vain hope
that, by doing what they used to do, will somehow make them faster than
doing what careful training had already proved to them made them faster.
Something about the reluctance of old dogs to learn new tricks?
ATP
I'm sure my technique is an abomination and more so at my physical maximum!
Do expert scullers maintain their best form at their maximum output? I guess
that's the goal of a good training program? I assumed, as you mention in the
beginning, that maximum power might lead to a slightly less efficient but
still more effective stroke. I'm following the discussion with much interest
although my personal aim is more toward a sustainable, moderate power output
over longer distances. (Hopefully combined with a neutral spine posture and
no hyper extension or flexion)
Regards,
Mike
Walter Martindale
Q. What's the most important part of the rowing stroke?
A. All of it...
W
Charles Carroll
Remember writing, "For as long as rowers continue to believe that
there is a perfect style or rhythm, we shall keep forcing ourselves
back into an unnecessarily constraining box."
I wonder. Could it be that we are constructing an unnecessarily
constraining box in the name of "scientifically sound technique?"
I keep thinking of Mike Sullivan's brilliant example from two years
ago:
"Let's say you had an 8 ft basketball player and a 5 ft tall
basketball player. Both try to dunk. The 5 ft basketball player has an
extraordinary 40 inch vertical leap but cannot quite dunk, misses by a
little bit. The 8 ft basketball player stands on his toes and dunks
without jumping.
"Thus does one conclude that the best way to dunk a basketball for
everybody is to stand on their toes."
No one is trying to throw technique overboard. They are just trying
not force the rower into an unnecessarily constraining box.
Zibi quotes Valery Kleshnev: "Instead of improving the efficiency of
rowing, which means minimizing the losses, we should focus of
improving the *effectiveness* of propulsion."
Call me naive but I think Kleshnev's admonishment is absolutely
brilliant. And it also seems to me to be very much in accord with
Fairbairn's idea that "You cannot learn to race by rowing, and you can
only learn to row by racing."
Cordially,
Charles
Charles Carroll
Maybe I can say it a little more concretely.
We all are in a process of trying to develop and improve upon our
skills, aren't we? Who doesn't want to take his skills to the next
level?
Now consider a sculler whose skill level is such that when he is long
at the catch he feels unstable, and for this reason is slow both in
inserting the blades and increasing force in the beginning phases of
the drive. But if he rows short he feels very stable and is fast at
inserting the blades and increasing force at the beginning of the
drive. In other words, rowing short improves the effectiveness of
propulsion.
Now how would you have him row?
Scientifically sound technique is to row long, isn't it? But given our
sculler's skill level rowing long will make him much less effective in
propelling his shell.
Would you nevertheless become Procrustes and lay him out on a bed of
scientifically sound technique and stretch him to fit this bed?
Fairbairn says trying to row to a longer point "kills the endless
chain movement, kills the rhythm or harmony." So just ditch this idea.
Row only to your strong point.
If a sculler rows only to his strong point, his "strong point will
become a longer point, till at last his strong point will be the
longest point to which he can reach."
I think this is all Valery Kleshnev is trying to get at when he says
"Instead of improving the efficiency of rowing, which means minimizing
the losses, we should focus of improving the *effectiveness* of
propulsion."
Cordially,
Charles
Charles Carroll
> in
> the UK public service - when HM Inspectorate of Constabulary
> certified
> that a police force was "efficient" I think they always meant
> "effective"
Richard,
Ah yes! A time honored trick of people who count votes. Whenever the
effectiveness of a policy or program is called into question, divert
attention by talking about efficiency.
While you can get almost everyone riled up about waste and
inefficiency, effectiveness in government is another matter
altogether.
I know a cowboy from Montana, a kind of philosopher of the saddle, who
likes to tell people that his Daddy always told him, "Just be thankful
you don't get all the government you pay for."
Cordially,
Charles
Carl Douglas
Charles, you conflate & confuse "long at the catch" with instability.
Who said these were or must be inter-related? If you row long but waste
no time, there will be no instability. If you hang around at the catch,
long or short, you'll probably be unstable there.
So the rest of your argument falls.
And what is, or even is the significance, of "your strong point"?
Strong for sitting there to look pretty without moving the boat
anywhere, or strong as in the strike of a Cobra, or in the flick of the
end of a whip? I would suggest that we don't have or need, nor can we
use, strong points. What we need is flow, continuity, speed,
elasticity, not postures & problems.
And please stop using effectiveness as meaning anything different from
efficiency. It is just a form of word drift. You can't exceed 100%
effectiveness, nor can you exceed 100% efficiency. I fear that you and
Zibi are getting wrapped up in a nice fuzzy feeling that this different
but similar-sounding word can somehow give you a few extra percent on
your performance. It just ain't so; this is science, where words have
clear meaning and measurement tells no lies, not the law or other
persuasive practices where words come to mean what you can persuade
others to believe they might mean & the outcome may owe little to the truth.