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Old 12-24-2014
Zenturtle Zenturtle is offline
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Join Date: Mar 2014
Posts: 1,898

Dived in the delta efficiency on google to see if there is more than Couzens article.
Its movingn through murky waters once you zoom in.
The whole human half mechanical, half chenical energy system is a complicated matter.
I understand the basic delte efficiency reasoning, but how this explaines the positives or negatives of a loping stroke style is unclear.

An interesting subject is the elastic capacity of muscles or the surrounding tissue. The whole loading and unloading of springs in the body seems to play a role in the whole stress and relaxation cycle during swimming.
I have a vague idea that big body movements can store and release more energy in a big stress and relaxation cycle. The whole loping riding a small body movement wave on top of a big body movement wave. Loading and unloading spring energy in a rhytmical manner.
Moving in vague voodoo territory there again.

Being a mechanical guy, I like to keep it simple.
We talked about this before I believe. Imagine having 2 identical swimming robots that can be programmed with 2 different stroke styles.
One program is Shirly Ripple pure rotation symetric stroke style, other is Phelps Ledecky loping stroke style.
We are having a swim robot race.
What program would you choose?
I think we both would choose the Shirly Ripple program. Right?

If we agree on that one, the question still stands
Why is Katie Ledecky (And lots and lots of other swimmers) faster when she lopes?
My opiniont at the moment.
- Its a stroke style that has been ingrained from an early age/learning stage when the need for air is a dominating factor.
- because it has been repeated so many times all energy systemes are optimised to this stroke style
- in the heat of the race one holds tight to old ingrained safe habits.
- it feels good
- Maybe there is some mechanism we are not aware of that make this strokestyle more efficient despite the seemingly straightforward mechanical disadvantages.

The last point is the most interesting.
Regarding the lifting over the water theory, I think there is something in it for some people.
Looking at the 10K men an womans stroke you will see more lopers in the men race like you said. I also thought maybe it has to do with a power to weight ratio, or a power to buoyancy ratio.
Heavy females with relative little upperbody power rarely lope, but that is the only statistic that can be conluded.
There is Phelps with a full kick, Paltrinieri with litlle kick, , Ledecky who isnt a great puller.... The swimming mystery continous....

Last edited by Zenturtle : 12-24-2014 at 11:56 AM.
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Old 12-24-2014
WFEGb WFEGb is offline
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Join Date: Jul 2011
Location: Hamburg
Posts: 1,104
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Hello Zenturtle,

...Being a mechanical guy, I like to keep it simple....
Brought me to think of my father in law's words (RIP). He built power plants: The only part that will never fail is the part you didn't incorporate...

Merry Christmas and best regards,
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Old 03-12-2015
Zenturtle Zenturtle is offline
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Join Date: Mar 2014
Posts: 1,898

A lot of other people also wonder what makes this stroke work
Time to polish up my french :-(

Charles seems to be everywhere (Energiesolaire)


Ouffffff ..... large (very large file).

First, from the outset, the crawler most impressive 100m I saw (in real life, and very often as it was in our club) had reached a style where each arm has a quite different role, so as you mention (and rightly so), rather asymmetrical. 49:27 100m in 1988. This is nothing new. And this is documented (among other EWMaglicho observed all this, I think he also quantified).

How to say.

When you teach (or learn) freestyle, you is symmetry. It is rather important. We must give a chance to adopt a logical style gesture, symmetric. Because at the time of learning, which often take years freestyle, years before claiming to have the supports without leakage, no longer frontal undue resistance * * at the time of this learning is no specific reason to focus on a specialization of the 2 arms. The asymmetry is considered a defect. The inability demonstrated by the swimmer to be symmetrical.

With time, talent surfaced. A swimmer will demonstrate an ability to swim very quickly (some over longer distances) in many feel the water, not to be unduly frontal resistance, good use of its segments. And according to the engine profile swimmer, his face, etc, it is possible that greater efficiency is achieved through some specialization of each arm, all of course heavily influenced by a breathing pattern in 2 times (obviously).

Good. This is where the fun begins. Here we swim in the not very well documented. These are just my impressions ...

Yes we can detect in this asymmetry, loss of efficiency. Possible that the left arm propels the body forward slightly less than the right. But also possible that some of that energy produces a lift effect up (lift), and raising the swimmer's body and therefore reducing (I do not know by what factor) hydrodynamic resistance coefficient. Also possible that the left arm simply deploys less energy than the right. AND this is where it gets interesting.

The Economy is defined by the percentage of the effort that you display that really makes you move forward. When a change in the velocity (the body forward) is observed if the energy level there is no loss, there is no real problem. This is an acceptable default.

Ah, you know, it's such a long history stuff. The history of injury, other styles mastered by the same swimmer (also a specialist crawler breaststroke does not swim front crawl like a crawler specialist fly), temperament, talent. Different molds give different styles, the key is the Economy (which includes hydrodynamise AND biomechanical efficiency). All these considerations allow latitude for acceptable compromises in order to take into account the human machine with which you work. If you do not understand or does not respect this machine * there *, you can do it swim better, but it can slow it.

* Edit * I just reject a glance. Chui convinced that there is no loss of economy in the arm that pulls shorter. I suspect a good old weight transfer, it locks the arms, rolling on his wrestling to lift a little up, but it does not cost that much fuel. As he performs a very long trial, the total wattage is limited by the duration of the event, no matter if it spends a little less energy on one side, the important thing is that it does not perish (in bad move) energy.

Last edited by Zenturtle : 03-12-2015 at 06:28 PM.
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