Shimano foot-stretcher and rowing shoe system?
RobP
http://boat.shimano.com/publish/content/global_rowing/en/us/Home/SRD600/Rowing_Shoes.html
PDF of installation instructions - which gives you some idea of how
the system is constructed is here
http://boat.shimano.com/publish/content/global_rowing/en/us/Home/SRD600/Foot_Stretcher.download.-mainParsys-000117-downloadFile.html/SRD_assembling_manual.pdf
In concept its similar to the "Krewklips" system that's been around
for a while (but the website seems to have disappeared). That system
consisted of a central boss that attached to the footplate, to which
were attached two single-sided bicycle pedals. So you could row in an
ordinary pair of cycling shoes (or sandals if you had a wet launch)
and clip your feet in and out of the pedals. I have used that system
for some years and it works pretty well. Provided the shoes have
cleats that are designed to release in any direction, its very easy to
extract your feet (any twisting motion will do it). At one point
there was some material on the ARA website, giving advice to safety
marshalls that this system positively did not require heel straps
(which would defeat the release mechanism.)
A claimed advantage of that system (and presumably also of the Shimano
system) is that it provides a mechanical advantage compared with
normal rowing shoes - in essence because the shoes rotate around the
mounting point, giving you a footplate with an angle that varies to
accommodate the flexibility of the individual rower. My own
experience on that front was inconclusive. I'm not sure it enabled me
to reach any further.
The other advantages (not having to share shoes etc) are all fine but
tend to be outweighed by the cost of retrofitting the boat and a pair
of shoes for each rower (though many rowers may have cycling shoes
already).
Interested to hear what others think. Is this a product that solves a
real problem, or just something to attract those with a fascination
for shiny kit and money to burn?
Rob P
Carl Douglas
Shimano have, for non-technical reasons, designed the system so that it
does _not_ accept normal SPD clips. As presently implemented, it is
also very heavy. I am disappointed.
Carl
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Henning Lippke
> also very heavy.
And 23 pages of instructions? That seems a bit ridiculous. Some might be
able to explain how to build a whole boat on 23 pages. Looks much too
complicated.
Christopher Anton
"Carl Douglas" <ca...@carldouglas.co.uk> wrote in message
news:7p1hc...@mid.individual.net...
>>
>> Interested to hear what others think. Is this a product that solves a
>> real problem, or just something to attract those with a fascination
>> for shiny kit and money to burn?
>>
>> Rob P
>
> Shimano have, for non-technical reasons, designed the system so that it
> does _not_ accept normal SPD clips. As presently implemented, it is also
> very heavy. I am disappointed.
>
> Carl
>
And not yet approved for use in England and Wales, although the NWSC has
seen a working example, they had a few questions which needed answering.
David Jillings
As someone who regularly cycles to the Boathouse, and who regularly
falls in from his single, I was wondering how I would like to be
swimming about with my cycling shoes on. Can't say the idea appeals,
but once I had got near the bank it would be nice to walk on the bottom
with shoes on rather than just socks.
David.
Tinus
allows the foot stretcher to rotate to keep the feet at the optimum
power transmission angle as the rower’s posture changes.
Does anyone have ideas about this optimum power transmission angle.
The feet have always been allowed to rotate and be at an optimum
angle. This system just allows the feet to rotate a bit more. Is that
an improvement?
Tinus
What about a mechanism which could store energy from the recovery
(kinetic energy which is normally lost) and release it during the
drive (much like those artificial limbs)?
The restriction of the classic rowing shoe might be such a system as
it stores energy by stretching the fabric of the shoe as the feet
rotate heels upwards. It releases this energy as the heels move down
again.
Alexander Lindsay
"Tinus" <martijn....@wur.nl> wrote in message
news:b801b339-b2ff-4c87...@u7g2000yqm.googlegroups.com...
SRD600 Foot Stretcher is equipped with a Virtual Pivot mechanism that
allows the foot stretcher to rotate to keep the feet at the optimum
Does anyone have ideas about this optimum power transmission angle.
The feet have always been allowed to rotate and be at an optimum
angle. This system just allows the feet to rotate a bit more. Is that
an improvement?
Am I alone in finding this stuff about "optimum power transmission angle"
complete nonsense?
First, and trivially, the stretcher does not transmit power, it transmits
force.
Secondly, the only useful force it transmits is horizontal, unless you
particularly enjoy coming off your seat. It seems to me that the mechanism
which allows the stretcher slope to decrease as you come forward will have
two effect:
1. it will decrease the horizontal component of the force on the
stretcher, which must be bad,
2. it makes the useful, horizontal, force on the stretcher more nearly
parallel to the toe-heel axis of the foot, which means that instead of the
force being roughly at right angles to the ball of the foot, as in standing
, running and jumping, it is along the foot axis, tending to crush the toes,
as in ballet pumps. Can this have any merit?
Maybe I am odd, but I like a very steep stretcher, basically because I want
to push horizontally. Where the angle is fixed by the boat builder, I
insert a wooden wedge between the shoe plate and the stretcher to achieve a
steeper angle. This seems to have no disadvantages, other than people
looking at me rather oddly. Does anyone think similarly?
Alexander Lindsay
Tinus
> to push horizontally. Where the angle is fixed by the boat builder, I
> insert a wooden wedge between the shoe plate and the stretcher to achieve a
> steeper angle. This seems to have no disadvantages, other than people
> looking at me rather oddly. Does anyone think similarly?
There are few people who are able to flex the ankle joint to an angle
a lot less than 90 degrees. Also the lower leg is almost vertical
around catch so the feet must be almost horizontal. A steep stretcher
doesn't help with that and may even restrict someone's ability reach a
good (or optimal) compression at the catch (if he's not flexible
enough). So this Shimano thing may actually be a good thing if one
prefers a steep stretcher.
What I am sceptical about is the lack of flexing of bones in the feet
which remain passive and don't bend as the ankles rotate. Shimano
calls this 'ease of motion'. I wonder if it is ease of motion which
one should strive for.
Carl Douglas
Everyone's different, so stretcher angles need to be adjustable. This
is very easily arranged without the need for mechanical complexity.
While I might not wish to row with a stretcher set to Alexander's
particular needs, I wholly concur with the rest of his posting.
KISS is a good design rule.
Cheers -
John E
they felt very good. Your feet do not flex at all so it all feels very
'direct'. However I would be surprised if there was an actual
efficiency advantage and the extra 1Kg per position and $400+ price
tag are offputting. Also they do not disengage with a twist off foot
motion so that needs checking out.
The (Japanese) demo was magic though. They gave you branded socks that
you wore and then got to keep and also a shoe horn marked with your
shoe size. All very odd and one of the US boat builders said they came
to their factory to demo them and the whole process was spread out
over three days and on the first day they never even got to see the
shoes....
John E
Checking the price more carefully, they are getting on for $800 for a
pair of shoes and a footstretcher....
SwissSculler
> Checking the price more carefully, they are getting on for $800 for a
> pair of shoes and a footstretcher....
...and there is nothing new to it...
but check this one:
the idea is as old as cloggs, but the angle makes a huge difference!!
Carl Douglas
Can you be more explicit, Frank? Which of the various sections of that
site had you in mind?
I see fancy sounding words & pronouncements but, as with the bumf behind
the SRD stuff, it seems so oversold to cause unease. I'm left to wonder
"Where's the beef?".
As seems to have been John E's experience, we were extensively consulted
by Shimano. This took many hours of our time (which we gave willingly),
but left us feeling that minds were already made up & that what was was
required was our uncritical approval, not our feedback.
We were asked to keep our meetings confidential, which of course we did.
We were told of an expected launch date, then Shimano went public way
before that without bothering to tell us. We registered our concern
over the great weight & mechanical complexity of their kit, only to be
told that as a couple of boats had been under weight at the last
Championships, that justified adding an extra kilogram per person in
equipment. We pointed out the unacceptability of requiring cycling
rowers to buy extra shoes (they'd modified the cleats to prevent the use
of normal cycling shoes!) but it seemed that commercial priorities had
over-ridden engineering logic & user convenience. We expressed concern
over the extraordinarily high cost, but that was also ignored. And we
now understand that similar concerns were expressed to Shimano by other
long-standing rowing businesses.
Tinus
> Can you be more explicit, Frank? Which of the various sections of that
> site had you in mind?
http://batlogic.com.au/BATLAB/RDNotes/tabid/153/Default.aspx
It's in the third note. They summarise a bunch of arguments to support
the claim that a flexed position of the foot/toes is bad. However none
of these arguments are conclusive and they only seem to be plausible.
The same arguments could also be used to claim, for instance, that
sprinters should not use the ball of the foot but the entire surface
instead.
Walter Martindale
While I don't always agree with everything in Kleshnev's rowing
biomechanics newsletter, I think that despite the lack of flash, the
information is more useful.
Sprinters would run more slowly if they used their entire foot.
"midfoot strike" running was something we found by accident to be
associated with fewer foot and low leg injuries in runners than heel
strike running.
A gradual student was looking to measure the effecs of orthotics on
the feet of runners and wanted to study the lateral moments at the
ankle (as well as all the other moments at the ankle) with a Kistler
force platform synched with a 500 frame/second "Locam" (it was the
80s, video wasn't as good as it is now). He spent quite a long time
looking for two groups of runners, those who had orthotics (got 20)
and those who didn't (found 10 runners in the Vancouver area who
hadn't been injured in the low-leg foot and didn't use orthotics).
All 20 of the orthotics users were heel-strike runners. 9 of the 10
uninjured runners were midfoot strike runners, one was heelstrike..
Feet aren't made to run with landing on the heel - that shock is meant
to be absorbed and reused by the muscles and tendons (e.g., Achilles
tendon), and the loads in sprinting are pretty darned big...
W
Carl Douglas
I presume we're talking about #7 in the "R&D Notes"?
1. Terminology! The ankle does not "transfer power", it transmits
force. One has to worry when so fundamental a distinction is
misunderstood in a document claiming a scientific basis.
2. Why is the ankle "not a power-producing joint"? Only if a joint
does not flex can it do no work. Are they assuming there is no flexion
in that joint? I don't think that can be correct. Indeed a fair
proportion of rowers, especially those of a short-legged persuasion,
will deliberately & usefully extend their feet at the finish.
3. It then goes on to discuss at what point the ankle "locks up". So
the ankle does flex! Mmmm.
4. I'm right with Walter. The human foot has evolved to transmit very
large forces through relatively small contact areas of its underside.
It, including the ankle joint & all the associated tissues, muscles &
ligaments, is a resilient section of a resilient system involved, inter
alia, in force transmission, in power production & in energy storage &
return. We're not designed to walk or run on fixed, flat feet, athletes
tend not to be flat-footed. Those animals better designed to run than
humans have evolved to use only what, in us, are the balls of our feet &
can no longer take ground contact loads on their anatomical equivalents
of our heels, even when standing.
5. It seems unreasonable to assume any single proper amount of foot
splay for a given foot. I'm sure they are right in hinting that
opposite feet might require different amounts of splay (since we're
rarely completely symmetrical) but I'm also sure that we need to vary
foot splay (& do vary it as far as equipment allows) through the stroke
cycle.
6. They would be right in suggesting that what feels most comfortable
will work best. Comfortable means not coming up against hard
restrictions. But that should not be dressed up as a scientific
analysis, nor be grandly termed "Advanced Sports Engineering".
My 2 pennorth -
Edgar
"Walter Martindale" <wmar...@gmail.com> wrote in message
news:9109534a-0c3b-435f...@f20g2000prn.googlegroups.com..
<snipped>.
> Feet aren't made to run with landing on the heel - that shock is meant
>to be absorbed and reused by the muscles and tendons (e.g., Achilles
>tendon), and the loads in sprinting are pretty darned big...
That is very true. I have always been a 'heelstrike' walker and my ankles
are paying the price a bit now, although it does not affect me in the boat
in any way.
Never been much of a sprinter anyway.
A long time ago I rented a flat and the people below thought I was clumping
around in heavy boots even when I was barefoot.
The main problem I have with it in Norway is that heelstrike walking leaves
you very prone to slipping when walking downhill on icy roads.