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  #21  
Old 01-07-2015
Janos Janos is offline
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Spitz, Thorpe, Popov et al will always look like they rotate more when compared to swimmers who have a more basic arm based technique.
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  #22  
Old 01-07-2015
Danny Danny is offline
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Somewhere on this forum (I don't know where any more) someone once posted a link to a very interesting historical article on the development of freestyle technique. I wish I knew where it was, or who wrote it, but I can't remember. What I do remember is that two major breakthroughs in technique occurred the 20th century. I'm not sure which order they occurred in, but one of them was when the Australians realized that you could swim faster by moving your shoulder forward as you spear and beat everyone else in the olympics. The other one was when people realized that body rotation could also speed things up. Before this time, good technique required one to swim flat with no body rotation. It would be good if someone can remember this article and point us to it.
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  #23  
Old 01-07-2015
borate borate is offline
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https://suite.io/bruce-iliff/165v2x3
http://en.wikipedia.org/wiki/Front_crawl

...among others
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  #24  
Old 01-08-2015
CharlesCouturier CharlesCouturier is offline
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Quote:
Originally Posted by Janos View Post
Spitz, Thorpe, Popov et al will always look like they rotate more when compared to swimmers who have a more basic arm based technique.
Their level of rotation would vary depending on the stroke rate most probably, but you're right. The idea I have of them swimming at moderate pace is that the body rotates, probably to at least 45deg.

Some studies have shown that "faster swimmers" rotate less, which I find a bit amusing since they're inverting things a bit. They observed that faster swimmers (therefore 50m specialists vs 200m specialists vs 800m specialists) rotate less, probably simply because their rate is higher. The higher the rate, the less time you have to rotate. Therefore swimmers having a higher rate probably rotate less, and since at that level they have rock solid grip, the higher the rate the higher the speed. That is how they (fallaciously in my opinion) concluded that rotating less is faster.

One thing which has interested me over the last couple of years, is the other axis of rotation, i.e.the shoulder axis. The body rotates along the long axis, but at some point, you end up with a shoulder in front of the other (i.e. when spearing for instance), therefore there's a rotation along another axis occurring. For me, that is the "shoulder rotation", although I wouldn't want to create a drift if this expression means something else (I did not study Hall Snr).

This axis is very important in my opinion, because given a nice catch and a solid grip, this means that the arm powered by this shoulder which is in front, and that is about to move back, will move backward virtually free of charge.

To me, it's the timing between this rotation, and the body rotation which is crucial. And at moderate speed, I can't see how 10deg (i.e. restricting oneself to 10deg) could be more efficient than allowing for "optimizing" this effect.
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  #25  
Old 01-08-2015
sclim sclim is offline
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Quote:
Originally Posted by CharlesCouturier View Post

One thing which has interested me over the last couple of years, is the other axis of rotation, i.e.the shoulder axis. The body rotates along the long axis, but at some point, you end up with a shoulder in front of the other (i.e. when spearing for instance), therefore there's a rotation along another axis occurring. For me, that is the "shoulder rotation", although I wouldn't want to create a drift if this expression means something else (I did not study Hall Snr).

This axis is very important in my opinion, because given a nice catch and a solid grip, this means that the arm powered by this shoulder which is in front, and that is about to move back, will move backward virtually free of charge.
The terminology for this forward moving shoulder is problematic. The spearing (starting at the top of the body axis roll, but following the roll back down again) shoulder moves forward as the pulling shoulder (moving up from its lowest point on the body axis roll) moves backwards, so we might call it a rotation. But this usually implies a solid lever connected to a joint which acts as the centre of rotation. In this case there is no actual central joint at the theoretical axis of rotation. For sure the two sterno-clavicular joints near the midline at the top of the sternum act together as a proxy joint for this movement, and the two clavicles (collar-bones) act as the two wings of this theoretical solid lever, but the actual movement is more "messy" than a simple rotation around this "proxy joint", even allowing for the fact that it is two joints close together, rather than one joint. The scapulae (shoulder blades) do a slidy-glidy movement upward on the posterior surface of the ribcage and attached muscles to allow this "rotation" to occur.

I probably am re-inventing the wheel here, reconstructing the movement in my head form theoretical considerations. I'm sure the formal swimming kinesiology community has formalised and standardised the terminology. I'm just curious if they refer to this forward shoulder progression as a "rotation" around an "axis"

And as for "virtually free of charge", I have to defer to your experienced swimmer's actual body-sense for the mechanics of propulsion. I can see that you get a longer reach than a non-experienced swimmer would achieve only rolling on the body long axis and reaching up (forward) with his arm on a shoulder joint that is sitting on the end of a shoulder girdle that is "not-rotated" in the coronal plane (i.e around the central top of sternum axis). But I cannot intuitively see that this longer pull due to a further reach and follow-through pull would be achieved with superior energy efficiency, which I see that your experience definitely recognises an energy saving here.

Last edited by sclim : 01-08-2015 at 07:45 AM.
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  #26  
Old 01-08-2015
Zenturtle Zenturtle is offline
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Quote:
This axis is very important in my opinion, because given a nice catch and a solid grip, this means that the arm powered by this shoulder which is in front, and that is about to move back, will move backward virtually free of charge.
Yep, I think thats one of the main items where the body helping the arms comes in.
I stll do standing straight opposite arm dryland windmilling at an elevated rate,
If you draw a line between the 2 shoulders looking at the person from the front that line is at an angle of about 30 degrees, The shoulder with the arm pointing to the sky is 10 cm higher than the normal position, the shoulder with the opposite arm pointing down is 10 cm lower than the normal position.
So the shoulderjoint moves together wioth the arms, and so moves the foundation of the arm together with the arm.Keeping the arm in static strain you rotate the foundation in a cirkel/ellipsabout 10 cm forwards and backwards,
This extra reach you get nore or less for free.You are paddling the connected arm while not moving/contracting the arm muscles.
Not really of course, the trunc-shoulder connection is producing power, but using these muscles can reduce the stress on the arm movers.
When doing the dryland windmilling its possible to experienmce this effect.
When relaxing the arms its possible to drive the windmilling arms a bit with only shoulder and tbody rotation.
When shifting from opposite arm windmilling to normal stroke timing *more catchup)
this effect deminishes and less connection between one shouder and the other is present.
They are startung to work against each other when shifting to catchup stroke.
The rotary shoulder driven style has its advantages looking at it from this perspective,

Maybe interesting to try Sclim.
Stand straight, level your pelcis and hold good general posture. Think of a rod sticking out the ground thats the central rotational swimming axis of the main body.
Head doesnt move.Only hte arms and shoulders are free to move when the body is twisted and rotated from the ground up.
Now start the opposite staight arm windwilling.
After a while your shoulders start to become fatigued.
Now relax the shoulder/arm muscles a bit and see the arms more as relaxed weights. Try to drive the rotating weights more with the rotation upperbody movement and the muscles around the shouder joint.
When doing this its possible to keep the arms spinning at a reduced arm stress and increased body load.

When used to this effect, shift your arm timing to catchup.
Or start from catchup and shift to opposite windmill timing, this is easier.
Curiouis to hear from your (or others) experience doing this exercise.

basically there are 3 movements
- rotating around the swim axis
- moving the shoulder up and down *forward and rearward in swimming direction)
- the windmilling arm action (talking about the movement plane of upper arms, not the relative timing betyween the arms)

I try to combine this
https://www.youtube.com/watch?v=_OJEno_q4y8

helping to drive the movement of the arms in the windmilling plane
https://www.youtube.com/watch?v=Hse-A2Mg8cw
The gurl is bending a bit too much, Body should be kept straight and streamlined. Head motionless.

Last edited by Zenturtle : 01-08-2015 at 11:02 AM.
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  #27  
Old 01-11-2015
Zenturtle Zenturtle is offline
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Another way of looking to the differnce between shoulder and hip driven is looking at the stenght of the connection line between shoulder-shoulder or diagonal foot-shoulder.
Until the arm timing is at the edge of front quadrant (90 degrees between entering and pulling arm) the shoulder -shoulder connection is nearly fully intact.
When timing shifts to more front quedrant rstroke the foot-shoulder connection becomes more dominant.
Its not black and white. There can be various strenghts in connection along those 2 lines.

Last edited by Zenturtle : 01-11-2015 at 01:26 AM.
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  #28  
Old 01-12-2015
CoachDavidShen CoachDavidShen is offline
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Coming late to this very interesting and long thread - I found this on Rod Havriluk's site Swimming Tehcnology Research: http://www.swimmingtechnology.com/in...isconceptions/

Misconception #2. In freestyle, hip rotation increases hand force.

In freestyle, the torso rotates about the polar axis (a reference axis through the center of the body from head to feet). The concept of “summation of forces” requires that successive body segments (e.g. torso, upper arm, lower arm, hand) rotate in the same direction (as in throwing). The freestyle arm motion is perpendicular to the torso rotation and the hand force cannot be increased by the force of hip rotation. Although the timing of the push phase in freestyle is usually simultaneous with torso rotation, rotating the hips harder or faster will not increase hand force. Exaggerated torso rotation can even produce counterproductive motions. For example, forceful torso rotation synchronized with the push phase can result in hand motion that is more upward and sideward than backward, producing a sudden decrease in hand force.

If I were to analyze body rotation, I would first say that it was a necessary evil in freestyle - we need to be able to go to the other side simply to be able to use the other side to stroke. Stroking on one side isn't as productive as stroking on both sides.

The second thing I would say that it is true that there is less rotation when the tempo gets faster. There is no choice because you need to reduce rotation to keep up with the faster tempo.

The thing that I've come to observe and believe is that body rotation when executed properly means that you've created sufficient tension in the body to allow for a good, strong, stable base to execute limb movements from. When you try to rotate your body faster, your body generates tension to make this happen faster - without tension, it will be like trying to roll a big bag of jello back and forth - very hard, slow and not a stable base to move limbs on. So properly generating tension, with the aid of you wanting to rotate your body, will allow you to better execute stroking/spearing actions to propel you forward.

my two cents...
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  #29  
Old 01-12-2015
Zenturtle Zenturtle is offline
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yeah thats an old one from Rod, I agree with him for the middle part of the stroke where propulsive surfaces are mostly kept facing the line of travel, but in practice thats not the case at the start and the end of the stroke.
Here a rotation along the bodyline is connected with a surface thats under an angle, so rotation is producing a force vector thats partially pointing in the line od forward movement.

Just look at this girl swimming.
A scrappy stroke from a TI perspective, but look closely and swear on a bible that bodyrotatin has no influence on propulsion

Lane 2, second lane from the front. B series HIght rate 2BK
http://www.swimmingworldmagazine.com/ne ... -triumphs/
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  #30  
Old 01-12-2015
CoachDavidShen CoachDavidShen is offline
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Quote:
Originally Posted by Zenturtle View Post
Lane 2, second lane from the front. B series HIght rate 2BK
http://www.swimmingworldmagazine.com/ne ... -triumphs/
hey can you repost that link? it somehow got messed up upon posting. thx
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