Thank you to every one who replied to my letter about understanding the
velocity of canoeing. I am comparing technique of canoeing on an ergometer
and on the water. I asked whether the negative velocity values associated
with the hand while canoeing on the water could be compared with the positive
velocity values of canoeing on an ergometer.
You suggested that velocity needs to be relative. In my study i made it
relative to the canoe on the water and to a fixed marker on the ergometer.
>From this the water data produced a negative value during the pull phase of
the stroke against positive values for the ergometer. Other areas of the
stroke had similar patterns such as the exit of the paddle and return of the
paddle.
Responces to the letter suggested that the two sets of data could be
compared, the negative verses the positive.
A point that was repeated is that the velocity is related dirrectly to the
force required to move the canoe of turn the fan in an air braked ergometer.
It would be usefull to measure this force through strain gauges on an
ergometer and the bending loads of the paddle on the, this does does require
some further thinking.
At present my study is focusing on the foces required from both areas. These
are represented in the velocity of the stroke and also the angle of the elbow
(greater the force the more the kayaker will bend the elbow and so shorten
the lever). One other area which is altering technique between canoeing on
the water and on an ergometer is the return of the paddle. Once the paddle
exits the water it is actively lifted and returned to a position to once more
enter on the water. On an ergometer this is assisted by the recoil of the
fan and so a greater percentage of the movement is passive. I would like to
comment further but am still trying to work out what the mechanism are at
present. Any help or questions on any of the above would be much appreciated
Jonathan Redshaw Brunel University
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velocity of canoeing. I am comparing technique of canoeing on an ergometer
and on the water. I asked whether the negative velocity values associated
with the hand while canoeing on the water could be compared with the positive
velocity values of canoeing on an ergometer.
You suggested that velocity needs to be relative. In my study i made it
relative to the canoe on the water and to a fixed marker on the ergometer.
>From this the water data produced a negative value during the pull phase of
the stroke against positive values for the ergometer. Other areas of the
stroke had similar patterns such as the exit of the paddle and return of the
paddle.
Responces to the letter suggested that the two sets of data could be
compared, the negative verses the positive.
A point that was repeated is that the velocity is related dirrectly to the
force required to move the canoe of turn the fan in an air braked ergometer.
It would be usefull to measure this force through strain gauges on an
ergometer and the bending loads of the paddle on the, this does does require
some further thinking.
At present my study is focusing on the foces required from both areas. These
are represented in the velocity of the stroke and also the angle of the elbow
(greater the force the more the kayaker will bend the elbow and so shorten
the lever). One other area which is altering technique between canoeing on
the water and on an ergometer is the return of the paddle. Once the paddle
exits the water it is actively lifted and returned to a position to once more
enter on the water. On an ergometer this is assisted by the recoil of the
fan and so a greater percentage of the movement is passive. I would like to
comment further but am still trying to work out what the mechanism are at
present. Any help or questions on any of the above would be much appreciated
Jonathan Redshaw Brunel University
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For information and archives: http://isb.ri.ccf.org/biomch-l
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