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Old 09-17-2018
WFEGb WFEGb is offline
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Join Date: Jul 2011
Location: Hamburg
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WFEGb
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Hello ZT,

Quote:
Werner, imagine having a 40 x 100 cm plank en pulling that plank through the water while rotating that plank back and forth at the same time. Can you imagine how much force that takes?
Now imagine that plank being flexible so it can twist a bit while you rotate and pull it throug the water. Is this costing more or less energy? The flexible plank is easier to pull through the water while rotatiing.
Think you've my answer some lines down yourself :-) At least pulling or pushing through the water will be easier done with a log than with a rubber-block. And some rotation is necessary for a recovery (or it will become uncomfortabel and highly inefficient). If you simply undock hips and shoulders -or twist the front of the rubber-block- you'll find automatically loss in streamline or balance-issues caused by miss-alignment or in the rubber-case internal friction losses.

Quote:
A plank is stupid and a body can be smarter than a flexible plank. A smart flexible body is much more eficient than a dead treetrunc in combined propulsion and drag optimisation.(dolphin)
The dolphin is a wrong example here. He's getting his whole forward-movement from well tuned movement of is body-muscles. That's what some elites show the first meters after turn or at start, not FS, quite complicated and difficult, because most of us don't have dolphin like muscles, their admirable coordination skills and feet like dolphin-flukes... If I remember right, fishes which swim forward with help of their fins are always stiffen their core, unless they want to go right or left.

Quote:
Only when the body is drawn through the water without rotation a stiff body held in optimal shape is better.
And a stiff body is better than a wrong moving body offcourse.
See above... But the rotation doesn't matter. It's "simply" easier to lock hips and shoulders... and (might be more important) healthier for the lower spine.

Quote:
Maybe its also because TI likes the body traveling forward statically on the edge for a long time with short shifts to the other edge. Glide on edge--shift---glide on edge.
During that glide on edge its not effective to have your body twisted. Thats where your idea is coming from that keeping everything in line is better from a streamline perspective.

If you like the continuous roll model better, then the continuous change of twistangle is more effective (for optimal propulsion drag compromise). Thats my favorite model , although the difference its not completely black and white.
Yes, "Hold the line (in skate)" - "Draw the line (recovery-fingers)" - "Switch (Spear and rotation)" is a mantra in our beginners courses. But as posted several times, later on "Hold the line" will be modified to "..and set the catch"...

Just today I realized it's difficult to distinguish from tuned continues roll in rhythm to hold the edge during the recovery. Where I found the latter offers more powerful spears and helps "effortless without loosing energy" rotation to the other side, if (and only if) I do not undock my hips and shoulders.

Black and White... Seems to me everything in swimming (and not only) is modyfied individualy. I recognize all my students just by having a short look at their recovery from outside, although they are doing well...

Best regards,
Werner
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