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“ When changing direction at each end of the stroke, the energy involved with moving (kinetic energy) has to reduce to zero. This energy is about six
times higher with the flywheel fixed compared to floating… ”
Dr I Bernstein, et all, Institute of Human Performance,
University College, London
Click here for article.
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...the differences you should be aware of
The ROWPERFECT rowing simulator is the first rowing machine whose design philosophy
is to truly simulate the dynamics of a light racing shell, floating on water. The main frame and seat simulate the boat, and the main bar simulates the water.
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- Rower moves a lighter mass (17-23kgs) relative to himself.
- Boat or RP moves far more than the rower, whilst the head and torso of the rower remain almost still.
- Labile seat optimises balance and promotes equal loading of the spinal column.
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- Rower moves his body relative to an immovable support.
- Body acceleration at the catch and finish are approximately six times greater than
in the boat or RP.
- Head oscillates up to two metres per stroke.
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Simulator or Ergometer – What’s the Difference
Look at the diagrams above – they clearly show the difference
between a fixed rowing machine and a rowing simulator (or rowing boat).
On a fixed ergometer, the rower moves his entire body mass up and down the slide, and must absorb large amounts of
momentum at the beginning and end of each stroke, when he stops before the next stroke/recovery. This energy is about 6 times higher with the flywheel fixed compared to floating. The Rowperfect’s
floating flywheel dramatically decreases the risk factor for injury to body structures absorbing kinetic energy.
In a racing boat, the rower is attached to only 17 - 23kg, which will move far
more than he does every stroke. The rower’s muscles, ligaments and tendons must absorb considerably less energy, and are therefore less likely to be injured. The Rowperfect’s moving mass is 19kg and
thus the “feel” (scientifically known as Proprioception) is virtually identical between a Rowperfect and a well-rowed racing boat – the rower trains the correct reflexes, so that when he returns to
the boat, his Co-ordination Pattern (TECHNIQUE) is exactly as it should be.
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ROWPERFECT DYNAMICS IN A NUTSHELL
For the correct simulation of the dynamics of a racing shell, at both turning points, at the catch
and at the finish, the moving mass of the flywheel/stretcher combination is essential to train the correct coordination and timing. In addition to that, the speed/force relation of the handle during the stroke
should also be as identical as possible to that in the boat, because this is essential to have a good "feel" during the stroke itself.
A good simulation of the "feel” during the stroke itself
can only be obtained when the following condition is met: The kinetic energy of the rotation of the flywheel at the average flywheel speed during a stroke should be equivalent to the kinetic energy of the
translation of the boat at the average boat speed during a stroke.
This condition is met by the combination of sprocket size and the moment of inertia of the flywheel of the Rowperfect It then results in the
same drive time (same speed of muscle contraction) as in the boat; provided the correct resistance disk is chosen
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In its patented design ( Patents: U.S.Patent 5,382,210 European Patent 0 376 403 B1)
the flywheel assembly weighs about 19 kgs, which is almost exactly the middle of the range of the weight per rower of most racing shells (Including oars and attached water).The seat is labile, as is the case in
a boat, forcing the rower to sit - and row - symmetrically.
These changes may seem quite revolutionary, and you may wonder why they have been made, and why they are so important. Exactly what are the
benefits of the sliding carriage and a labile seat?
Firstly,
increased safety for the user. The labile seat forces the rower to sit symmetrically, which helps to equalise the loading on each side of the spine. The sliding carriage reduces the inertial forces acting on the rower at the beginning ("catch") and end ("finish") of the stroke because the rower's body speed Is reduced by around six-fold compared to the situation on a fixed rowing machine. The result is a smoother action, with much less energy to be absorbed by the rower's tendons, ligaments and cartilage at those turning points.
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Secondly,
the "feel" is very different to a fixed ergometer - it is much smoother, and almost identical to the feel of a racing shell. To define "feel" requires a very short explanation of what "feel" really is:
The medical/scientific term for feel is proprioception. It has two components. The special sense of proprioception is located in your middle ear. It gives us information on acceleration and
deceleration, and balance. The general component of proprioception derives from pressure and tension receptors in your joints, muscles and tendons. As you row on the Rowperfect, whose dynamics virtually replicate
those of a floating boat; your sense of proprioception is receiving almost exactly the same signals as would be the case in a boat without the extraneous information of wind, weather, and waves and so on. This
allows you to truly concentrate on producing a perfect rhythm and technique, which is after all the perfect coordination of your muscles by your nerves.
“I have never
told it before, but for three weeks before the World Championships of 1989 I was unable to row in the boat, and rowed exclusively on the Rowperfect. This gave me an advantage over my competitors; because I was able
hone my timing at the catch to perfection, unhindered by wind or waves.” Frans Goebel
Every rowing machine hitherto invented has behaved like a boat which is tied to the wharf. By allowing
the resistance mechanism to "float", the Rowperfect allows you to experience the feel of a free-floating boat.
Although the Rowperfect does simulate a racing boat very closely, there are one or two
important differences:
- Because oar handling technique is not required, deterioration of that technique due to fatigue will not serve as an automatic safeguard for the oarsman against over-exertion, as
would happen in a boat.
- Because the oarsman does not have to push the oar away at the beginning of the recovery, but instead is partially pulled back by the elastic shock cord, there is a tendency to row at
a slightly higher stroke rate than in the boat.
- Unlike the water, the main bar is not of infinite length. Therefore, to stabilise the position of the rower within this finite length, there is a slight downward bend in the main
bar, with its lowest point at approx. 40 centimeters from the hind leg. In order to influence the dynamics of the system as little as possible, the curvature of this bend is kept at a minimum.
- The unit should be levelled in such a way that when rowing, neither of the two support legs is touched by the main frame or the seat. For leveling the unit the front leg is provided
with a level adjustment bolt. Turning the bolt clockwise lowers the front end, turning it anti-clockwise raises the front end. When adjusted correctly, the lowest point of the bar will be between 1 and 1.5cm
below the highest (front) point.
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Comparison of fixed and dynamic Rowing Machines
On analysis, the two most critical points in the rowing stroke
where technique can make a difference to raw power are:
(1) How the coordination of the catch is carried out, and
(2) Same for the finish.
1. This should be done so as to place no backward pressure onto the stretcher that is not transferred via the blade in the water and then levered forward against the
oarlock which in turn moves the boat. Any Backward pressure without the counter balance of force in the opposite direction against the oarlock results in the boat being driven backwards. Put simply
this would mean the rower has crashed their body into the front stops and stretcher before taking the stroke or has started the stroke (leg drive) without connecting with the water. Try doing this on
the Rowperfect and see how the machine responds. It will fairly quickly force you to concentrate on the ‘proper’ approach and application for the catch. Initially this will be a challenge and require
significant concentration in order to maintain the carriage and seat working in a stable central position. You have it right the forces are in equilibrium
when the seat stays more-or-less stable
2. The same logic applies at the finish of the stroke. On the fixed platform machine you can bash into the front as much as you like or for as long as your back and body
can take it. I'd suggest that for those who haven't tried. Learn how to get it right on the Rowperfect then get off and onto the Concepts. If you are not left with the immediate impression that
one of them was like rowing and the other something quite different I'd be very surprised.
Jim Battersby
Australian Champion Sculler, Olympic and World Medallist rower
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