traction topic. banned from the TI forum?

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traction topic. banned from the TI forum?

Post by SA on Sat Sep 22, 2018 11:58 am

Cant get acces anymore to the TI forum. Too many post or to many non positive TI posts,  I dont know.
Any way, analysing arm traction during the underwater pull lately, and some TI swimmers seem to slip quite some water.
Using these forums as a sort od diary, so just starting to analyse the traction of lopers. So I just continue on this forum, between my old friends again....
Helping Cottmiler to keep this forum alive haha
Its about the slipfactor, that is the amount the hand moves back during the underwater stroke, devided by the amount the head moves forward.
Tricky bit is to find the point where the hand starts to move back relative to the water. Its intersting what the forearm angle is at this point. How much water you do push down at the front, do you wait to press back till your arm is vertical, or does that take to much time?

Just a quick dump of pics. Lopers have an asymmetric staring point also it seems. lets find out if thats the case with most lopers etc

Sun starts his backwards handmovement at his breathing side at a shallower arm angle than at his non-breaqthing side.
That seems pretty logical, since the breathing side is pushing water doen more mostly in an asymmetric stroke. But its all a bit hard to see at his angle.

Sun 1R


Sun 1L
free image upload

Wiil find out his slipfactor. another time.

if anyone is intersted, I copy the traction threads from the TI forum to this forum.

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Re: traction topic. banned from the TI forum?

Post by cottmiler on Sat Sep 22, 2018 5:28 pm

I can,t work on the forum at the moment as I don,t usually have internet.
Will be back in October.

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Re: traction topic. banned from the TI forum?

Post by Don Wright on Sun Sep 23, 2018 10:04 am

SA wrote:...Its about the slipfactor, that is the amount the hand moves back during the underwater stroke, devided by the amount the head moves forward.
Tricky bit is to find the point where the hand starts to move back relative to the water. Its intersting what the forearm angle is at this point. How much water you do push down at the front, do you wait to press back till your arm is vertical, or does that take to much time?...

A very interesting topic! I've often been mystified by the way some FS-ers are actually able to drive their arms through the water as fast as some of them do - thinking that they must, to a large extent, be "spinning their wheels", and their arms are not making fully "productive propulsive" contact with the water!  As for the angle the stroking arm makes with the surface - I thought it was common knowledge that, until the major under-side of the arm (hand/forearm) was at least 45 degrees below the surface - it was just a waste of effort and likely to upset balance.  Which is why the down-sweep to a catch is said to be non-propulsive.  I know by an early "curling-over" of the hand immediately after entry, one can achieve a form of "catch", up close by the surface (e.g. as in fly!?) - but how effective is that, compared with introducing more of a "backward-facing" forearm/hand? (says he - obsessed with his EVF catch! Smile )


I wonder how an old acquaintance (lost contact with him yonks ago) would have succeeded - in the later part of his FS arm recovery, he was fond of driving his hand and forearm directly down into the water (a very quick EVF!) - never mind the niceties of the down-sweep!  Of course that action lifted his head clear of the water at each arm entry,  so there was a lot of up/down motion! He was also a keen amateur rugby player - so accustomed to using a lot of force, with little finesse!!!

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Re: traction topic. banned from the TI forum?

Post by Tom65 on Tue Sep 25, 2018 7:27 am

Looks like Ti is locked, to us at least, but since nobody is posting.
Pity.
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Re: traction topic. banned from the TI forum?

Post by SA on Sun Oct 07, 2018 10:05 pm

yeah, nothing special, they shut down the forum and are moving to facebook , just like swimsmooth.
I think its a bit of a mess, a facebook type forum.

I will have a further look sometime when the arm is really starting pressing back, but for most of the swimmers this is even before the arm is 45 degrees down.
this is the starting point of the hand going backward. Dont know when the elbow is also going backward making a full paddle. Thats a bit later, and even later with a high elbow catch.
Anyway I was surprised to see so much downpushing on the water.

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Re: traction topic. banned from the TI forum?

Post by cottmiler on Mon Oct 08, 2018 10:48 am

I don,t know if you can get in to TI forum but if so then you could add to your signature “I am now on theswimforum.palstani.com”

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Re: traction topic. banned from the TI forum?

Post by Tom65 on Tue Oct 09, 2018 4:15 am

Nah. Can't get into sinature edit.
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Re: traction topic. banned from the TI forum?

Post by Don Wright on Tue Oct 09, 2018 10:17 am

SA wrote:...
I will have a further  look sometime when the arm is really starting pressing back, but for most of the swimmers this is even before the arm is 45 degrees down.
this is the starting point of the hand going backward. Dont know when the elbow is also going backward making a full paddle. Thats a bit later,  and even later with a high elbow catch.
Anyway I was surprised to see so much downpushing on the water.

Yus! A lot of bods seem to aim for some early-arm propulsion after water entry, by starting to flex the wrist, curling the hand over a bit, before getting the rest of the arm a bit lower and at a somewhat steeper inclination to the surface, employing more of the forearm/upper-arm.  But I wonder how much of that early action is actually useful - if it is counter-acted by the legs drooping slightly adding to drag - due to pushing down in that early part of the downward sweep, rather than back?  At least with an EVF, think the idea is to make the down-sweep more of a (notional  Laughing) "drop", than a deliberate downward propulsive action - so it shouldn't have as much affect on balance.

When, earlier, I mentioned "Spinning the wheels", I was thinking about car-drivers trying to get started over an icy stretch.  There seems IMO to be some sort of limit to "wheel turn-over rate" in order to achieve some sort of purchase or grip with the ground.  Maybe that analogy isn't applicable to the rate at which a swimmer's arms can usefully drive through the water (a law of diminishing returns for increase in effort expended" - exhaustion!  Rolling Eyes )? Doesn't frontal drag increase massively as one tries to increase forward speed - ultimately, almost like trying to swim through a wall of reluctantly yielding water? (Can just imagine "cottmiler" grinning, and saying that's just Newton's Law "Every action has an equal and opposite reaction."! )

On further thought, I've just remembered what Maglischo wrote about arm/leg action "Always try to pull/push/kick into relatively undisturbed water" - for maximal propulsive "return" on effort expended! So in that sense, a slower arm action might be more productive propulsion-wise - because it gives a "short instant" for the water (disturbed by earlier rapid arm action) to return to a more steady state beneath the body, as the latter moves forwards. At 60 stroke cycles/min, that's 0.5 sec/arm stroke - and thinking about the adjacent water mass surrounding the stroking arm as it does (say!) a strong up-sweep of the arm - I wonder what the effect on that mass of water will be when that stroking arm comes around again 1 second later. Obviously the body should have travelled further ahead, so the "water disturbance" will not be as great as if the body was in a fixed position - and in any case, the momentum backwards of the former mass of water (surrounding the path of the previous arm stroke) will have soon waned!

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