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  #131  
Old 02-02-2011
FrankJ FrankJ is offline
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Quote:
Originally Posted by haschu33 View Post

We try to find the explanation for something that works. Developing an explanation first and then try if it works will not neccessarily fail, but in this case the explanation(s) - or science - itself is too vague to be able to base anything on it.
I was just about to book a trip to mainland Europe for me and my family. But this made me think, we would be wiser to swim across the channel. It'll be safer to rely on my intuition, than on faulty attempts to control fluid dynamics such as planes or boats.
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  #132  
Old 02-02-2011
CoachEricDeSanto CoachEricDeSanto is offline
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OK. I think we are beginning to calm down now. I want to clarify that there has not been any statement in the DEBATE that has been offensive. I was offended by the statement, " you must read a book on high school physics." That statement says that my arguments are completely ignorant. That is not true. I am thick headed in the sense that I can be slow on the uptake. I do not deny that. I am just trying to clarify what to me seem like discrepancies in responses to my arguments. I have said a few times here that I am enjoying this. I believe debate between intelligent people is (almost always) good. (I will hold the possibility that debates can run completely astray and not be helpful. Ours may have done that.) But I am still interested in improving my understanding. Perhaps Lawrence and I can continue this over email so as not to annoy other readers. I completely agree that science understanding is not necessary to improve swimming. And I completely agree that swimming may be too complicated to be able to explain with relatively simple arguments like both Lawerence and I are proposing. I also enjoy the possibility that "simple" Newtonian physics MIGHT be able to explain what we see and feel. It would make it easier to teach to swimmers like Lawerence and myself who LIKE to have the scientific understanding. It is in this mindset that I risk continuing. And, please, if anyone is bothered by the debate, please let us know and we will continue this in private messages.

So here goes.
Bowling ball example - Lawerence agreed that when the string between the bowling ball and the body reaches full extension the body feels a tug forward. I agreed that the initial push throwing the body and ball forward and therefore the ground pushing us by 3rd law is the only force acting on the whole system. So it sounds like you are saying that to total distance the body travels would be the same if you just jumped down the lane with no ball as if you jumped, through the ball and then the ball pulled you. Is that correct? That is what I get out of "no added propulsion". In this case the body throwing the ball would move more slowly at first then catch up when the ball pulls it and the no ball person would move faster at first and not get the pull so they end up in the same place. If I am now correct, which I think we are now saying the same thing, then is there a situation where the ball can experience more resistance when thrown so that it no longer can pull the body but the body still only moves as fast/far as in the original ball push. This is what I was trying to say back at the beginning with the less resistance to the spearing idea. If the recovering arm gets resistance through muscle tension and drag inducing spearing, then the body would accelerate as if it threw the ball and not get the advantage of the later tug.

Jumping example - You said that the force of the floor pushing up on the body is the only force acting. I agree. So it sounds like you are saying that if a jumper throws their arms upward with 15 lbs of force, then the body is accelerated downward with 15 lbs of force added to gravity. I don't understand how this can explain why the arm movement increases jump height. It sounds to me that the jumper would have to increase jumping force by the 15 lbs and then more to increase the jump height. I think the jumpers leg strength would not change. Even if the elastic potential of the muscle and tendon were loaded with the extra 15 lbs, that should just match the force needed to overcome the arms and reach the same height as with no arms. I can see how your argument would say the jump heights would be the same. But I can't see how you say that 3rd law explains the higher jump with the arm swing. In my mind, if F=ma, then the arm swing can effectively lighten the body because the momentum of the arms can pull the body upwards, then the same force from the legs would have less mass to move and therefore accelerate it better. I can predict that you would say that upward acceleration of the arms must cause and equal and opposite downward acceleration of the body. I accept that this may be true, but then I can't see how the jump would improve.

Last edited by CoachEricDeSanto : 02-02-2011 at 06:53 PM. Reason: my hands type faster than my brain thinks
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  #133  
Old 02-02-2011
Lawrence Lawrence is offline
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Eric, I apologise for offending you. It was not my intention. I will reply more fully later.
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  #134  
Old 02-02-2011
haschu33 haschu33 is offline
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The never ending thread...

fconti72, when you can come up with a scientific model for our swimming this is most wonderful and I will greatly welcome and appreciate it. Actually I am really looking forward to something like that. So, please, go ahead, don't hesitate. If that is the outcome of this thread it is simply hilarious.


Otherwise - what you think about science, your instruments, the channel,... it's all up to you and I cannot see what I have to do with it.



What is it that you want from me?

Last edited by haschu33 : 02-02-2011 at 06:51 PM.
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  #135  
Old 02-02-2011
FrankJ FrankJ is offline
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Quote:
Originally Posted by haschu33 View Post
The never ending thread...

fconti72, when you can come up with a scientific model for our swimming this is most wonderful and I will greatly welcome and appreciate it. Actually I am really looking forward to something like that. So, please, go ahead, don't hesitate. If that is the outcome of this thread it is simply hilarious.


Otherwise - what you think about science, your instruments, the channel,... it's all up to you and cannot see what I have to do with it.



What is it that you want from me?
Can you point to me the post where I declared that I could provide a model to describe the movement of a swimmerís body in water? No? And you know why? Because that post does not exist.

Anyway, as you ask, what I would like from you, is to know what laws bodies obey when in the water, as it is not Newton. Quotes from you on the inadequacy of science DO exist.

Otherwise, I would like to have a normal debate. I donít enjoy being sarcastic, and I donít want to bring you offence. But I donít appreciate sweeping (and vague) statements on the limits of science in the face of the presumed complexity of some discussion. That is, for three reasons.

First, a minor one, as it is personal. I work as a scientist. Statements like the ones above are superficial and dismissive, and suggest and underlying attitude that I find quite offensive. And not uncommon.

Second, no one denies that science has its limits. But given that it has explained processes way more complex than the ones we are trying to discuss, I find it unlikely that humanity will face the limits of scientific inquiry in explaining why we feel a forward squirt when extending. It would be quite pathetic, really.

Third, statements on the vagueness of science as formulated above, in addition to being vague themselves, are non relevant for what we are talking about here. They promote a defeatist approach to discussion, and serve mostly to end a debate. Like: how does an embryo develop? We canít explain it. It must be magic! Excuses, really for not even trying to work on a problem.

And, I do find the specific questions interesting. Mostly because of a basic motive: for me TI works. I feel better in the water, swim better, and enjoy myself more than I ever did before. Therefore, I would like to know why. And is seems pretty clear I am not alone in this. We have thought on engineering and neurobiology embedded throughout this forum and the TI material.

Nevertheless, answers to the 3 questions in this thread included: statements on forward motion deriving from downward rotation, cryptic and senseless references on boats moving the wrong way (I thought I was hallucinating), claims that motion in space infringes the laws of physics, and so on, to end with a general dismissal of science as a valid system of thought. This based on the unsupported (and slightly arrogant) assumption that the problems we are talking about are too complex.
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  #136  
Old 02-02-2011
Lawrence Lawrence is offline
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For the sake of avoiding further confusion, let's distinguish two positions:

1. A non-swimmer can't learn to swim just by reading a book or understanding a theory. It takes practice in the water.

2. A swimmer can't improve his stroke just by reading a book or understanding a theory. It takes practice in the water.

I assume we all agree with 1.

I argued above that 2 is highly questionable, although I understood it to be something Terry holds true. So let's break 2 down further.

I gave the example of a swimmer twirling her fingers underwater at the Olympics. I assume a coach or engineer suggested it would help reduce drag. If it did, that looks like an example which contradicts 2. Perhaps what Terry is saying is this: fine, she got the idea from a coach and he got it from a book or scientist, but in order to execute the stroke adjustment properly she had to practise it in the water. Without such practice she wouldn't have been able to perform the twirling well or at all. So, in the end, it's our experience in the water that is the root of all improvement.

I have no quarrel with that reasoning, but it fails to address the point that she got the idea from somewhere else. Physics, engineering, video analysis, inner ear balance organ studies - the list is potentially endless - could be sources of such ideas. I would think that means they too could be the origin of insights which would otherwise be lost to the swimmer.

You might reply that a swimmer with a lot of patience and creativity could, in principle, and with a lot of trial and error, discover all of the adjustments that science and the rest come up with. I suppose that is possible, although given that the number of adjustments one could make is countless, it doesn't sound likely. But we don't need to decide the point since whatever the truth of the matter it is surely also possible that we would reach those insights much more quickly by other means, scientific ones being the most obvious candidates.

On this basis it seems to me fanciful, to say the least, that the only way to improve one's stroke is by relying on intuition or experience in the water.

('Intuition' seems an unhappy term here, by the way, given the quality of our intuitions about how to move efficiently in water. See, for instance, Terry's recent point about advancing his technique after deciding to spear into the water at an angle that 'felt too steep'. Wasn't intuition saying go flatter?)

Last edited by Lawrence : 02-02-2011 at 09:16 PM.
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  #137  
Old 02-02-2011
haschu33 haschu33 is offline
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fjconti72,
we two seem to have a fundamentally a quite different view point. I am not quite sure how to answer your post, sorry, my fault. I have to do it later.

To free me from the accusation of not being interested in solving the details ;-)
here a little reply to Lawrence post.

Quote:
Originally Posted by Lawrence View Post
...
2. A swimmer can't improve his stroke just by reading a book or understanding a theory. It takes practice in the water.
...
I argued above that 2 is highly questionable, although I understood it to be something Terry holds true.
If 2 is highly questionable, what is the correct statement then?
Something like this:
"A swimmer can improve his stroke just by reading a book or understanding a theory. It doesn't take practice in the water."
What is the version you are comfortable with, and which you wouldn't question?

(the markings in Lawrence quotes are from me)
Quote:
So let's break 2 down further.
I gave the example of a swimmer twirling her fingers underwater at the Olympics. I assume a coach or engineer suggested it would help reduce drag. If it did[, ...

but it fails to address the point that she got the idea from somewhere else
Well, I don't know about this example. We don't know why she is doing it, we don't know what exactly she is doing, we have no clue about the exact or even the vague purpose of it and we don't know where she got it from. This entire example is based completely on assumption, and I fail to see how it can serve as an argument.


Quote:
...But we don't need to decide the point since whatever the truth of the matter it is surely also possible that we would reach those insights much more quickly by other means, scientific ones being the most obvious candidates.
I wish scientific ones would be the most obvious candidates. Truely.
My perception is, that in the area of swimming science is extremely vague. Not even the question whether propulsion comes from drag or lift is settled. All I found about it is vague. There are very few studies on swimming, a great deal of them 10 years old or even older. Being precise, i have to phrase it this way: that scientific material that I am able to access is very thin. But nobody else comes up with tons of scientific material about swimming either. There are a lot of viewpoints, opinions, statements and so on. But if you take a close look it is backed up by a lot of experience, a lot of physical explanations that might be true, or not. But not really by a lot of scientific studies.

Maybe I am a little thick headed. But could someone come up with a list of scientific publications about swimming that clarifies details about propulsion, catch, pull, weight shift, rotation, spearing, recovery, stroke rate, stroke lenght, drag, lift, balance... I find only very little. Could be entirely my fault, don't worry. Perhaps I will be able to understand then what some of these arguments are about.

Quote:
On this basis it seems to me fanciful, to say the least, that the only way to improve one's stroke is by relying on intuition or experience in the water.
Yes it would be fanciful, but who denied it in the first place?
Ok, maybe I am a little thickheaded again, too tired from reading, but who, and where, said that that the only way to improve one's stroke is by relying on intuition or experience?

I get the feeling that the basis of our discussion is a bit of a mirage.
And, Lawrence, sorry, put the blame on me, but I don't get your point in this post at all.


Think I should go to bed...

Quote:
('Intuition' seems an unhappy term here, by the way, given the quality of our intuitions about how to move efficiently in water. See, for instance, Terry's recent point about advancing his technique after deciding to spear into the water at an angle that 'felt too steep'. Wasn't intuition saying go flatter?)
Yes, I agree, Lawrence, the term 'intuition' definitely needs some clarification.


Hang on in there...
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  #138  
Old 02-02-2011
CoachEricDeSanto CoachEricDeSanto is offline
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I am glad I have the day off today. I couldn't keep up otherwise.

I would say that statement 2 needs a little wordsmithing. As it now reads it is entirely true. A swimmer cannot improve technique without practice. But that is different than saying experimenting in the water is the only source of how to improve. I would think we all agree that there are many sources from which we can learn techniques to try. That is, after all, the whole point of a forum like this.

I think it is fair to say that the vast majority of people on the planet would look at the fact that a group of intelligent and scientific minded people can discuss the physics of a technique that we are all pretty confident works for several days and not come to a conclusion as to why it works as reason to just measure stroke counts, perceived exertion and interval times and say that is good enough for them. I think those of us who like to dig deeper for a reason why are a very small minority.
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  #139  
Old 02-02-2011
Lawrence Lawrence is offline
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Quote:
Originally Posted by haschu33 View Post
If 2 is highly questionable, what is the correct statement then?
Something like this:
"A swimmer can improve his stroke just by reading a book or understanding a theory. It doesn't take practice in the water."
What is the version you are comfortable with, and which you wouldn't question?

The rest of my post deals with that.

Well, I don't know about this example. We don't know why she is doing it, we don't know what exactly she is doing, we have no clue about the exact or even the vague purpose of it and we don't know where she got it from. This entire example is based completely on assumption, and I fail to see how it can serve as an argument.

There are two obvious possibilities: (a) she made it up in the pool, and (b) her coach suggested she do it, based on theoretical analysis. I think (b) is more likely. You haven't offered anything on this front. Sure, I can't prove (b) is true but it seems reasonable. That is how one builds a case. What do you suggest instead?

I wish scientific ones would be the most obvious candidates. Truely.
My perception is, that in the area of swimming science is extremely vague.

You seem to think homeopathy is beyond science. So I'm not going to waste time arguing about the merits of science with you, or its potential to elucidate what happens in swimming.

Maybe I am a little thick headed. But could someone come up with a list of scientific publications about swimming that clarifies details about propulsion, catch, pull, weight shift, rotation, spearing, recovery, stroke rate, stroke lenght, drag, lift, balance... I find only very little. Could be entirely my fault, don't worry. Perhaps I will be able to understand then what some of these arguments are about.

The point is that science may explain a lot about how swimming works. Or should we rule out physics right now? If so, how do we analyse weight shifts and, as the TI freestyle DVD puts it, 'cooperating with gravity'? A lack of scientific publications on swimming hardly shows a scientific approach is pointless.
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  #140  
Old 02-02-2011
Lawrence Lawrence is offline
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Quote:
Originally Posted by CoachEricD View Post
Bowling ball example - Lawerence agreed that when the string between the bowling ball and the body reaches full extension the body feels a tug forward. I agreed that the initial push throwing the body and ball forward and therefore the ground pushing us by 3rd law is the only force acting on the whole system. So it sounds like you are saying that to total distance the body travels would be the same if you just jumped down the lane with no ball as if you jumped, through the ball and then the ball pulled you. Is that correct?

Sorry, I'm not following this.

Jumping example - You said that the force of the floor pushing up on the body is the only force acting. I agree. So it sounds like you are saying that if a jumper throws their arms upward with 15 lbs of force, then the body is accelerated downward with 15 lbs of force added to gravity.

Yes, assuming for simplicity that the upper and lower body have equal mass.

I don't understand how this can explain why the arm movement increases jump height. It sounds to me that the jumper would have to increase jumping force by the 15 lbs and then more to increase the jump height.

No. Throwing the arms up and simultaneously 'throwing down' the legs cancel each other out, so that they don't subject the body to any net force. But the extra 15lbs of force directed downwards is applied to the floor, which reacts by pushing back on the jumper with 15lbs of extra lift. This helps accelerate the jumper upwards so that he attains a greater speed at lift off and hence jumps higher.
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