straight arm traction

[Zenturtle]

This girl has exceptional good traction.
Slipfactor = amount of handslip/ amount of head forward movement= 10/17.5=0.57.
The avarage swimmer in your local pool has a slipfactor of about 1.5-2 at half the speed.
slipfactor is minimised by low drag, high traction, little speedvariation.


straight 1r


straight 2r


straight 3r


https://www.youtube.com/watch?v=auO0L9hmP0E

to be more precise, starting point is where hand is definetely is starting to move backwards. Thats ok here, hand is even blurred by faster movement.

the newer, more prcis slip factor becomes:
handslip 12.5 -1= 11.5
head movement 20.5 -4.5 = 16
slipfactor =11.5/16= 0.72
So, worse than 0,57, differnce 0.15, but still..who does it better at this pace?

[sclim]

OK, so how does she do it??


"slipfactor is minimised by low drag, high traction, little speedvariation."


That's it??

[Zenturtle]

haha,well yes. Thats what it comes down to for an outside observer.
I keep it smple this time haha. How you achieve that is another question...

[sclim]

Reading between the lines, I think to myself, you mean, all my obsessive taking notes, trying to micromanage all the exacting details of how to grab that extra millimetre of length on each stroke, by keeping that exact elbow flexion angle that is the average of all those elite swimmers out there...turns out to be wasted intellectual exercise, because the efficiency actually has got nothing to do with that elbow angle or any other easily measured external detail that the obsessive video analyser can glean. It's actually due to some mystical hidden secret sauce that can't be transmitted. At least not easily transmitted, with some simple rule that the beginner can easily follow. Sigh. Again.

Actually I'm only half joking. Perhaps a useful working rule might be the 3rd factor you enumerated -- the "little speed variation" factor. One can actually take that and try to make use of that idea. Don't pull hard, increase the stroke force gradually, and spread the stroke force over a greater percentage of the stroke cycle.

[Zenturtle]

cant you send me some footage (pm ) of your stroke to make talking easier?

constant speed is an important one.
Imagine walking slowly 3km/h and dragging a 100 kg treetrunk through the water.
If you keep that trunk at a constant 3 km/h, you can imagine you dont need so much force to keep it floating forward. A bit of water flowing around it, walking very slow....
Now vary the speed of that treetrunc between 1 and 5 km/h in an alternating manner, whilke keeping the avarage speed the same 3km/h.
You can almost feel your arms getting tired already from pulling that thing forward and releasing it all the time instead of just dragging it forward calmly.

[sclim]

Originally Posted by Zenturtle

cant you send me some footage (pm ) of your stroke to make talking easier?

constant speed is an important one.
Imagine walking slowly 3km/h and dragging a 100 kg treetrunk through the water.
If you keep that trunk at a constant 3 km/h, you can imagine you dont need so much force to keep it floating forward. A bit of water flowing around it, walking very slow....
Now vary the speed of that treetrunc between 1 and 5 km/h in an alternating manner, whilke keeping the avarage speed the same 3km/h.
You can almost feel your arms getting tired already from pulling that thing forward and releasing it all the time instead of just dragging it forward calmly.

No, you don't need to convince me further -- I fully agree with your logic. In fact, use the infinitesimal calculus approach and imagine the swimmer undergoing variations of, say, + and - 1/4 mph. He may well enjoy the rest while he slows 1/4 mph and benefit from the lack of needing to put out as much power when he decelerates and coasts at his new speed of 2.75 mph. But then he has to accelerate to 3.25mph again (to keep his mean speed at 3.0 mph). This acceleration costs him more power than he saves during his deceleration. Equally dismaying, his energy cost overcoming drag at 3.25 mph (which is proportional to the cube of his velocity in the water), despite the saving at 2.75 mph, will always add up to more than that of the swimmer who doesn't vary his velocity and keeps precisely at 3.0 mph all the time.

Now, to develop the skill and the co-ordination to keep at 3.0 mph all the time without thinking so hard about it that something else screws up...as you say, that's another thing again.

The video thing is particularly awkward in the pool where I spend almost all my time. They have a thing about cameras due to an incident a few years ago. I may try and work something out, maybe. Or at another pool.