The Propulsion Paradox

[sclim]

Originally Posted by Zenturtle

A good 2bK has a bit of this movement, but more in a corkscrew way.

Somehow I've never looked at 2bk this way before. But the idea seemed intuitively correct to me once I got thinking about it. It was initially hard to sort out in my mind, but I think I finally got it -- each paired and simultaneous left up and right down kick can be calculated as an Archimedean (corkscrew) impulse that has 2 components -- one directed backwards, driving the swimmer forwards, and another component that imparts a rotatory force tending to rotate the trunk so the right hip rises and the left hip sinks. But this impulse happens in the context of following a similar prior rotatory force in the opposite direction, so the current force serves to decelerate this prior opposite rotatory velocity down to zero angular velocity, and then to a positive rotatory velocity in the new direction... and so on.

The propulsive usefulness of this alternating rotatory force has escaped me up till now but it makes complete sense now. I also see now it has its parallel in a slight but very real left right alternating rotatory trunk-pelvis sequence that can be analysed within the predominantly up down and forward sequence of forces in the running gait.

[Zenturtle]

The old skool kayak timing swimmers used a crokscrew action to kick themselfes into the opposite side catch.
Building a bridge between the extended arm and pressure on top of the opposite kicking foot.
Look at the slomo from 4 min10 to 4 min 30.
https://www.youtube.com/watch?v=ktSW6ozmnzk.
This balances the forces at the front and back and gives a rotation at the same time.

The very 2BK basic body twist is the same as TI, its only connected to a faster catch in the above style instead of a spear and glide.
https://www.youtube.com/watch?v=xBeKxMpEORM

How much can it be compared to dolphin kick? Not that much I am afraid.

[Danny]

Originally Posted by Zenturtle

The old skool kayak timing swimmers used a crokscrew action to kick themselfes into the opposite side catch.
Building a bridge between the extended arm and pressure on top of the opposite kicking foot.
Look at the slomo from 4 min10 to 4 min 30.
https://www.youtube.com/watch?v=ktSW6ozmnzk.
This balances the forces at the front and back and gives a rotation at the same time.

The very 2BK basic body twist is the same as TI, its only connected to a faster catch in the above style instead of a spear and glide.
https://www.youtube.com/watch?v=xBeKxMpEORM

How much can it be compared to dolphin kick? Not that much I am afraid.

I think the kayak timing refers more to the motion of the shoulders than the arms, and it is also worth noting that there is something of a kayak motion that the hips do as well. Not sure how these two kayak motions are synced together, but my sense is that the spearing shoulder may be down when the opposite hip is up. In this sense, it is an undulation, just like a dolphin kick.

[Janos]

Some things you can't learn from video, and you can't copy them. You have to intellectualise the theory and then apply it.

[sclim]

Originally Posted by Janos

Some things you can't learn from video, and you can't copy them. You have to intellectualise the theory and then apply it.

Very true. Perhaps even further, going beyond intellectualise, we must internalise the principles and somehow actually feel the process working the magic within your own body. But for me, working mostly without a hands-on coach, the only way I can get to that last magic stage is to understand the principles correctly first, and that means, for me, watching appropriate videos, thinking and maybe getting expert commentary from others, so that I can formulate exactly what is going on, so I can understand how to achieve the same thing myself. Then a lot of trial and error, then if I'm lucky enough to recognise that I'm doing it right, continuing to do the same until the instinct develops.

[sclim]

Originally Posted by Danny

and it is also worth noting that there is something of a kayak motion that the hips do as well.

That's true, Danny, but the difference is that the "kayak style" label was used in the arm movement description because there was an alternative, that is, "front quadrant style".

In the hip girdle movement description (apart from drawing attention to the fact that the hip to hip line can wobble in a movement that draws the outline of two point-to point cones in 3 dimensional space) there doesn't seem to be much merit in giving it the same kayak name. After all, it isn't actually possible to make hip movements in isolation -- "patient lead hip" wouldn't make sense.

[Danny]

Originally Posted by sclim

That's true, Danny, but the difference is that the "kayak style" label was used in the arm movement description because there was an alternative, that is, "front quadrant style".

In the hip girdle movement description (apart from drawing attention to the fact that the hip to hip line can wobble in a movement that draws the outline of two point-to point cones in 3 dimensional space) there doesn't seem to be much merit in giving it the same kayak name. After all, it isn't actually possible to make hip movements in isolation -- "patient lead hip" wouldn't make sense.

Hi Sclim, I think what I am trying to say is that it is not entirely clear to me that the "Kayak Style" label is inconsistent with front quadrant style. I agree that the emphasis is entirely different, but, to use the metaphor of "inside out swimming" that is so often heard here, the kayak motion of the shoulders are driving the stroke. How and when you do the catch is another issue. I would say that the opposite of a kayak stroke is someone who is not using their shoulders at all when they swim, but is instead trying to do it all with a vertical forearm. As for the hips, it is true that the hips don't have as many degrees of freedom as the shoulder girdle, but I feel that I too often tend to neglect the necessary motion of the hips in my stroke. This all depends on where you are in your stroke evolution and also where you are trying to go, but I find for me right now concentrating on the kayak motion of my shoulders and coordinating it with the kayak motion of my hips helps me to power my stroke in a smooth and comfortable fashion.

Note, by the way, that one doesn't talk about a patient lead shoulder any more than one talks about a patient lead hip. The notion of a patient catch has more to do with the elbow to the hand than it does with the shoulders. I think that there may well be motion in my shoulders even while I am trying to be patient with what I am doing with my elbow and hand. I am talking here more about how it feels than about exactly what I am doing, because, to tell the truth, I know the feeling better than I know the motion from an outside point of view. The reason I am trying to describe this in detail is because I myself would like to unravel what it is that I am doing. That said, I still would be careful not to confuse the motion of the shoulders with the motion of the elbow and the forearm.

[Zenturtle]

I think the label shoulder driven kayak stroke and combining this with `using only small shoulder muscles` is completely wrong.
Yeah, its using extra shoulder rotation, but its the whole shoulder complex, and this shoulder complex is connected to the hips, and the hips are connected to a 2BK often.
Thats what I like about the posted old skool swim footage. They are obviously swimming with the whole body and not only with the shoulders.
A girl like Janet Evans cant have been such a great swimmer if she is only used small shoulder muscles.
She hardly had shoulder muscles.

[sclim]

Originally Posted by Danny

Note, by the way, that one doesn't talk about a patient lead shoulder any more than one talks about a patient lead hip. The notion of a patient catch has more to do with the elbow to the hand than it does with the shoulders. I think that there may well be motion in my shoulders even while I am trying to be patient with what I am doing with my elbow and hand. I am talking here more about how it feels than about exactly what I am doing, because, to tell the truth, I know the feeling better than I know the motion from an outside point of view. The reason I am trying to describe this in detail is because I myself would like to unravel what it is that I am doing. That said, I still would be careful not to confuse the motion of the shoulders with the motion of the elbow and the forearm.

OK, I got distracted by the hip part of what you started out with in the prior post. Back to the shoulders, what you were saying was that the front quadrant (variable rotation speed) motion of the arms and hands occurred even at the same time as a kayak motion activity of the shoulder girdle. I completely missed that the first time you mentioned it, and I must admit, I never even thought of that, even before that, all the time I was thinking of the "either front quadrant / or kayak motion of the arms and hands."

Now the shoulder girdle isn't completely rigid -- we just often think of it as a single rigid rod passing through space between the shoulder joints. In actual fact it is two separate complex structures, each having a sliding surface (shoulder blade) and a pivot point (sterno-clavicular joint) at its medial (near the middle portion). So it actually can perform an independent left from right motion. It is not constrained to be a kayak paddle. I have not thought out exactly what movement it performs -- and it may be hard for me to work it out by myself. My head hurts, too much information for now! But I'll sleep on it

[Zenturtle]

stop thinking too much guys,

do this for a few lenghts and try to find out how why it also can help your swimming
https://www.youtube.com/watch?v=47R995eM9B4