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  #21  
Old 04-28-2013
Richardsk Richardsk is offline
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I might add that the English in the article, although very good, is not perfect, but perfection is hard to attain, even for English speakers.
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  #22  
Old 04-28-2013
CharlesCouturier CharlesCouturier is offline
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Thanks Richard, great article indeed.
Here's another interesting take at the same case, though I have to insist, the purpose of this thread wasn't to address the concepts discussed and studied in this article:

http://umanitoba.ca/faculties/kinrec...tationSwim.pdf
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  #23  
Old 04-28-2013
Richardsk Richardsk is offline
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Thanks Charles

The English in that one isn't perfect either, with less excuse since the author appears to be an English speaker, and really people should get the Latin names of the muscles right. It's rectus abdominis not abdominus, but I suppose only POFs (Pedantic Old Farts) care about that sort of thing. ;-).
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  #24  
Old 04-28-2013
hydrophobe hydrophobe is offline
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Charles, I wouldn’t criticize your English. My second language is French. Your written English is probably better than my written French.

My point is that you over-complicate the discussion by unnecessarily trying to use tech terms, which even if you understood them, would not add value. Then, you finish with “that’s undeniable”.

You are clearly very knowledgeable about swimming, so there is no need to de-value your posts in this way.

I respect that you started this thread in a spirit of inquiry, so I will take a shot at giving a little help in the areas you talk about, though I’m not convinced it helps illuminate your point. I am rusty and haven’t used this for a long time, so someone with a more current working knowledge may have something to add.

Chemical energy is delivered to the body through food. It is converted by the body into heat energy and, when demanded by the body, mechanical energy.

Energy is conserved; it can neither be created nor destroyed. The act of moving the body transfers chemical energy from within the body to its surroundings in the forms of heat and mechanical energy. The unit of energy is the Joule (J).

Power is a measure of the rate of energy transfer and is measured in Joules per second (J/s) or watts (w).

Force, in newtons, (N) can be measured at any given moment in time, by dividing the power generated, by the velocity at which an object is moved. It can also be found from multiplying the mass of the object you are moving, by its acceleration.

The point is that, if you have any energy transfer at all, there are always forces being set up and power generated. None of these properties are translated into any other property.

It’s just fine to say that you feel that something you observe is similar to a certain motion in swimming… you are well qualified to say that and the fact that you take the time to try to find new analogies is useful to those of us who are trying to understand swimming mechanics.

Returning to the lawnmower case, I think you make a good point. In order to start the engine, a hard tug is required on the cord and the body’s rotation may be similar to that used in fc rotation… This is absolutely true. If you wish to do a decent job of pulling back on the cord with the right hand, (assuming your spine is the central axis of a clock and your nose represents the hand) you would drive the clockwise rotation of your trunk with the right leg. If you rotate far enough, you would eventually have muscles in tension (left side?) and in some in compression (right side?), all of which would then work to return your trunk to its equilibrium, i.e. facing straight ahead.
By the way, the return to equilibrium rotation is a freebie, since, though you did the work of rotating that far initially, it was necessary to perform the cord pulling function correctly. Any additional work you can do with that return rotation is just a bonus. Of course, the cord returning to its starting position would help to return the trunk also, but let’s ignore that for a moment.

Thinking about this in an underwater setting, imagine you are floating in water and about to perform the same motion. The foot is not fixed of course, so let’s imagine you kicked out against the water. Much of the drive is lost, because the kicking foot wastes energy on uselessly displacing water… but some of of it would displace (rotate) your trunk. The coil effect is less marked also, but present nevertheless. Your trunk and legs wouldn’t rotate at exactly the same time. There would be a slight lag, with one catching up the other and equilibrium being achieved. I’m not sure which would rotate first, but I guess the legs and hips would go first, creating a coiling effect, then the trunk would follow as the spinal muscles uncoiled…

I’ve just re-read what I’ve written and I’m truly not sure if I have helped in any way at all :)

On your comment about allowing trunk rotation to do most of the work in bringing the arms back during the (traditionally named) pull phase, I couldn’t agree more. The videos posted on another thread, showing swimmers propelling themselves by sharp trunk rotations (and arms falling back by their sides), are very good evidence of this.

I’m out of action with inflamed rotator cuffs partly as a result of being too shoulder driven, so please consider me a convert :)

PS: I was in Montreal a few years ago and was impressed by how easily people drifted into and out of French and English in the course of a single conversation… not because they didn’t know the correct word in either language, but because usage seemed to be subject-specific. Now THAT is an agile use of language :)

Last edited by hydrophobe : 04-28-2013 at 04:50 PM.
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  #25  
Old 04-28-2013
CharlesCouturier CharlesCouturier is offline
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Quote:
Originally Posted by hydrophobe View Post

My point is that you over-complicate the discussion by unnecessarily trying to use tech terms, which even if you understood them, would not add value. Then, you finish with “that’s undeniable”.
Again, read post #1. That one holds the main msg of this topic. It's kindergarden simple. The rest I'm just answering questions, providing clarifications, etc... Read post 1.

*edit* I just finish reading your entire response, and realize you probably read post one. So your discomfort is in regards to this bit of discussion here:

Quote:
Originally Posted by CharlesCouturier View Post
So simple still. And it's important, to have any relevance in this sort of discussion to be very careful with these details.

Body rotation alone can not generate propulsion, that's obvious.

It can not, not generate power though. Energy gets thrown in it, force gets generated, it can be then translated to power. That's undeniable.

Now the question being debated here is: can this power be translated into forward propulsion.
This is where I use the word *undeniable*.

That's how analphabets like me (who has never attend a single science class, and has no math) survive. I don't focus or question the undeniable, and kindly invite anyone to do the same. Motion is not possible without energy. Energy does create measurable metabolical activity. When vo2 is converted into watts equivalent, that's the measure called metabolical power. Does some of this metabolical power gets translated into mechanical power?

Simply stated. Metabolical power (costs of getting the body to rotate) turns into mechanical power to get the body rotating. That again is pretty much undeniable. Now does some of this power also gets translated into mechanical power required to get the swimmer moving forward?

And again here, I'll simply mention that muscular efforts are made to get the body to rotate. So if we take this portion alone, the body rotation, and isolate it... Here, a picture's worth 1000 words. On top of serving this discussion, note that it's an excellent drill to get rid of rotator's cuff niggles. I presented this drill a few times up until now, but with only 8 posts, I assume it may be the first time you ever see it:

http://www.youtube.com/watch?v=bHSYQ6BaM2A

Isolated rotation, is the closest you can get in 2013 from pure rotation. No drill even come close. BR is perfectly specific to that used during the full stroke action, no pause, bilateral breathing etc etc....

Note that the swimmer on this clip is moving at a pace close to, if not under 2min/100m. Aren't there a few people who would love to match this pace full stroke?

Now again, what do you see?

Swimmer is expending most of his energy doing 2 distinct things:
1. Rotating
2. Performing a gentle sculling action at the end of the rotation.

What do you see? What is responsible for propulsive forces here? Your opinion?
If we cut the Body rotation, then the swimmer would be left only with the little sculling action. Do you think the forward speed would be as fast? If not, why??????????????? lol

here, another fun question. Do you think you have any reason for not being able to match this swimmer's pace at this drill, given that it requires very little effort from the arms themselves, and that it requires Zero flexibility? If you are armed to perform this drill, but fail to match his speed. Why??????

If this guy picks up a kicking board and starts to kick, forget it mate. You will *not* follow him. Ankle flexibility isn't something that develops overnight. If he swims with a pull, forget it you're dropped. Pulling specifics mechanics is very complex.

In fact you know what? There's a very good chance that this guy on this clip just can not swim as slow, as your fastest pace over a kilo. This is why I persist in complexifying things. I still don't understand why, these fast guys can not slow down to most people registered on TI Forums dream pace!

Why??????????????????????????????????????????????? ??????????????

Last edited by CharlesCouturier : 04-28-2013 at 10:21 PM.
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  #26  
Old 04-28-2013
hydrophobe hydrophobe is offline
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Charles, since you say it's undeniable, I guess I should stop denying it. If you have succeeded in translating a force into power, then you should publish a paper and expect a Nobel Prize to drop through your letterbox ;)

But seriously... on the swimming front, thanks for posting the video. I did see it on another post, in fact itís one I referred to when I said that it proved that trunk rotation can do most of the work in bringing the arms back. I appreciate your suggestion to work at this drill during rotator cuff convalescence. I will try to add it to the exercises Iím doing presently (various forms of skate and kick drills).
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  #27  
Old 04-29-2013
CharlesCouturier CharlesCouturier is offline
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Quote:
Originally Posted by hydrophobe View Post
Charles, since you say it's undeniable, I guess I should stop denying it.
What I mention as undeniable is that this:

http://www.youtube.com/watch?v=JfJ-slsH93s

Or the body rotation portion of this:

http://www.youtube.com/watch?v=bHSYQ6BaM2A

Takes some energy. Mostly core muscles will expand this energy. The overall energy expanded can be measured. It usually is expressed in term of oxygen consumed. In a lab, they call this the vo2.

When comes the need to discuss economy, or efficiency (means the same thing), it's easier to use a common unit of measure, ie power. Force? I don't know what to do with it in the context of this thread.

So, feel free to deny. I'd feel very bad otherwise. All I'm saying after all, is that body rotation consumes energy.

What's open for debate, what's deniable, is does some of the energy used to rotate translates into propulsive force.
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  #28  
Old 04-29-2013
swimust swimust is offline
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Quote:
Originally Posted by CharlesCouturier View Post
What I mention as undeniable is that this:

http://www.youtube.com/watch?v=JfJ-slsH93s

Or the body rotation portion of this:

http://www.youtube.com/watch?v=bHSYQ6BaM2A

Takes some energy. Mostly core muscles will expand this energy. The overall energy expanded can be measured. It usually is expressed in term of oxygen consumed. In a lab, they call this the vo2.

When comes the need to discuss economy, or efficiency (means the same thing), it's easier to use a common unit of measure, ie power. Force? I don't know what to do with it in the context of this thread.

So, feel free to deny. I'd feel very bad otherwise. All I'm saying after all, is that body rotation consumes energy.

What's open for debate, what's deniable, is does some of the energy used to rotate translates into propulsive force.
3 stupid questions coming your way now:
the buoy... why does it needed? can this drill be done without the buoy?
isn't the buoy the anchor point?!
"just asking" ;)
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