Can anyone achieve this?

[Danny]

Originally Posted by Zenturtle

Do you mean this one?


I like to keep it simple , starting wih a treetrunc with arms. No bending allowed.
If this treetrunk is supplied with a smart core and is alowed to use it without feets separating and without bending, what would be the result?

Yes, I mean the quote from Suzanne that you are referring to.

I don't understand your question about tree trunks. What sort of muscles could a tree trunk use and how would they work? It seems to me that muscles move body parts, and if the whole body is rigid, there is nothing to move. You could put jets on the sides of the tree trunk to rotate it, but that is not muscle motion. So please explain your question.

[Zenturtle]

Ok, we cut the treetrunc into slices, drill a hole in the center and stick a rod through the hole to keep everyting aligned. Al the slices are connected with muscles (the core muscles).
On top of that we give it 2 wooden legs which have the same degree of freedom as a human leg.
So all the parts between shoulders and toes are free to rotate in an organised manner now.

What would be the optimal internal action between toes and end of tree to help its forward movement in the water compared to the stiff treetrunc with stiff wooden legs?

Or in other words, what is the essence of hipdrive without bending and without kicking?

[CoachSuzanne]

Originally Posted by Zenturtle

Do you mean this one?


I like to keep it simple , starting wih a treetrunc with arms. No bending allowed.
If this treetrunk is supplied with a smart core and is alowed to use it without feets separating and without bending, what would be the result?

nothing would happen if it was not allowed some bending in the core. Assuming there is some bouyancy somewhere that it could push right or left it would begin to rotate.

The video of charles rolling about occurse because he bends sideways...the lungs get outside the midline of the body and start to float, which caues the body to start to twist. But that's just a party trick, you don't use that in swimming. At least I don't see anyone using that who is skilled.

[Zenturtle]

I know the unassisted rotation clip and agree with your explanation.
In my view body bending can be used to improve propulsive power, but as far as I know Ti swimming, TI is more about always holding a straight line.

So, when no bending is allowed, to achieve hip drive, you need a kick?

[CoachSuzanne]

Originally Posted by Zenturtle

I know the unassisted rotation clip and agree with your explanation.
In my view body bending can be used to improve propulsive power, but as far as I know Ti swimming, TI is more about always holding a straight line.

So, when no bending is allowed, to achieve hip drive, you need a kick?

hmmm...this sounds like a trick question. hip drive to me implies rotation coupled with forward movment. To create rotation you need something to provide a "normal force" or some friction perpendicular to the direction of movement. if you have a stiff wooden torso and two stiff legs, one of the two legs needs to move to create that friction in order to produce rotation.

[CoachSuzanne]

Originally Posted by Zenturtle

I know the unassisted rotation clip and agree with your explanation.
In my view body bending can be used to improve propulsive power, but as far as I know Ti swimming, TI is more about always holding a straight line.

you're talking about a degree of undulation which will always be present of the kick is to provide forward motion.

I was told by a mech engineer triathlete that a straight legged alternating kick withotu any knee or torso bend will also provide forward movement but I dont' think it's the most efficient way for thehuman body to move forward.

[Danny]

Originally Posted by Zenturtle

Ok, we cut the treetrunc into slices, drill a hole in the center and stick a rod through the hole to keep everyting aligned. Al the slices are connected with muscles (the core muscles).
On top of that we give it 2 wooden legs which have the same degree of freedom as a human leg.
So all the parts between shoulders and toes are free to rotate in an organised manner now.

What would be the optimal internal action between toes and end of tree to help its forward movement in the water compared to the stiff treetrunc with stiff wooden legs?

Or in other words, what is the essence of hipdrive without bending and without kicking?

I don't think you have the right question, so I'll modify it a little bit and see if you can live with my changes. Don't just cut the tree trunk in slices, but also cut it parallel to its axis through the middle, so you can now slide the halves forward and backward with respect to each other. This is what happens when you reach forward with your extended arm and your hips on the same side move with respect to your hips on the other side. Now you can rotate the slices with respect to each other, but you can also slide them back and forth. But you have to keep everything absolutely straight. Now what is the optimal action?

I haven't the faintest idea, but at least now the question makes sense to me as a swimming analogue. I suspect that the answer also depends on the range of motion of your shoulder and hip joints, but I don't know this.

[CoachSuzanne]

Originally Posted by Danny

I don't think you have the right question, so I'll modify it a little bit and see if you can live with my changes. Don't just cut the tree trunk in slices, but also cut it parallel to its axis through the middle, so you can now slide the halves forward and backward with respect to each other. This is what happens when you reach forward with your extended arm and your hips on the same side move with respect to your hips on the other side. Now you can rotate the slices with respect to each other, but you can also slide them back and forth. But you have to keep everything absolutely straight. Now what is the optimal action?

I haven't the faintest idea, but at least now the question makes sense to me as a swimming analogue. I suspect that the answer also depends on the range of motion of your shoulder and hip joints, but I don't know this.

This may help you guys formulate your questions:
https://en.wikipedia.org/wiki/Fish_locomotion

[Zenturtle]

I can write a whole chapter of possible ways to swim that more or less use fishlike actions or not, but thats only making things more complicated.

Ok , we Have Dannys extra freedom of forward and rearward movement of bodyparts within the bodytube. The shouldercomples can be shifted forwards and the other side backwards without bending if you got the shoulderflexibility.
Thats a good way to increase arm power and range of movement.
The shoulders can also be rotated relative to the other bodyslices, but that goes against moving the whole upperbody as one unit. The tilting of the hip causes some spine bending, thats a bit of a bordercase if you want to stick to no bending allowed-

If I understand Suzanne right, a good kick goes together with some undulation.

hip drive to me implies rotation coupled with forward movment.

you're talking about a degree of undulation which will always be present of the kick is to provide forward motion.

Shelly Taylor Smith has an almost straigt leg kick, but I agree this style cant be used by everyone with the same effect. The straight leg lick can be a source for rotation, but for most not the most effective way to extraxt forward movement.
In principle the legs should get some traction on the water to help the rotation, right?
When Shinji kicks he gets a litle bend in his bodyline. He sort of kicks his butt to the surface.
Is that the sort of undulation you mean?

[CoachSuzanne]

Originally Posted by Zenturtle

I can write a whole chapter of possible ways to swim that more or less use fishlike actions or not, but thats only making things more complicated.

Ok , we Have Dannys extra freedom of forward and rearward movement of bodyparts within the bodytube. The shouldercomples can be shifted forwards and the other side backwards without bending if you got the shoulderflexibility.
Thats a good way to increase arm power and range of movement.
The shoulders can also be rotated relative to the other bodyslices, but that goes against moving the whole upperbody as one unit. The tilting of the hip causes some spine bending, thats a bit of a bordercase if you want to stick to no bending allowed-

If I understand Suzanne right, a good kick goes together with some undulation.



Shelly Taylor Smith has an almost straigt leg kick, but I agree this style cant be used by everyone with the same effect. The straight leg lick can be a source for rotation, but for most not the most effective way to extraxt forward movement.
In principle the legs should get some traction on the water to help the rotation, right?
When Shinji kicks he gets a litle bend in his bodyline. He sort of kicks his butt to the surface.
Is that the sort of undulation you mean?

I think reviewing various types of fish propulsion adds a lot to understanding what options humans have for movement. Size, amplitude, origin of body waves, and associated thrust development options (the box fish is my favorite...so cute!)

Here's a sentence from the conculsion of an article studying harminc wave speed and amplitude in human swimmers:

The variability among swimmers provides strong evidence that swimmers find their own solutions to the task of producing a body wave appropriate for optimal achievement of the task.

my take is that it's fun to think about and try different options..since humans are not designed to swim through water, we won't have one ideal way to make forward progress. The changes and differences in limb length, strength, bouyancy, distance, training history, etc. will all impact how an individual manifests their stroke and harmonics/undulations (speed & amplitude).

http://www.sciencedirect.com/science...21929008005538