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  #151  
Old 01-31-2017
Zenturtle Zenturtle is offline
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Thanks for the links. Straighforward usefull stuff.

I wonder if there is a experimental or theoretic optimum in negative or positive overlap as a function of effort level, speed and/or strokerate?
We all know constant propulsion kayaking sprinters often like to move more toward a catchup timing when they swim on half throttle.
Is it because they like to feel force in their stroke, even when swimming slower, (sort of a strenght and balance training), or has it anything to do with a different efficiency optimum under those conditions?

It would be very insightfull to have good footage of swimmers with low and high active drag numbers. Dow do they move through the water?
What exactly makes the difference? Smooth propulsion skills, balance, alignment?

Last edited by Zenturtle : 01-31-2017 at 05:47 PM.
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  #152  
Old 02-01-2017
borate borate is offline
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Havriluk's findings would seem to fly in the face of a chief TI tenet - the patient lead hand - at least at applied to non-sprints.

While not severe catch up, it does delay the stroke until the recovering hand pierces or nearly pierces the water - a negative index.

Last edited by borate : 02-01-2017 at 02:58 AM.
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  #153  
Old 02-01-2017
Zenturtle Zenturtle is offline
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I agree with the constant propulsion idea to a large extent.
Its almost a no brainer for achieviing maximum sprint speed.
But a more catchup timing can be a better idea at lower effort levels.
Just wondering where the shifting point lies.
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  #154  
Old 02-01-2017
WFEGb WFEGb is offline
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Hello,

Quote:
But a more catchup timing can be a better idea at lower effort levels. Just wondering where the shifting point lies.
Might be interesting to know the theoretical pinpoint. But it might not be the individual best. (In Formula 1 the drivers are able to drive faster curves in their own (different) paths than the theoretical calculated... The Theory seems not exact enough...)

Except for some drills Terry advocates a never resting arm. And his catch is (almost) set up (in a passive drifting way) when the recovery arm enters the water. (That's not what the "extended overgliding myth" tells about TI...)

Best regards,
Werner
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  #155  
Old 02-01-2017
RodHavriluk RodHavriluk is offline
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RodHavriluk
Default Arm Coordination

Glad you find the info useful. The index of coordination (IdC) is the concept that has the potential to make the biggest improvements in freestyle swimming.

The theoretical optimum is an IdC of just over +30%. The current fastest swimmers rarely exceed an IdC of over +10%. There is much room for improvement.

Itís absolutely natural for a human, whether paddling or swimming, to rest twice on every cycle, even if itís only for a fraction of a second. However, the result is a negative IdC with gaps in propulsion for a less efficient use of energy. A swimmer can maintain a positive IdC, generate less force on each arm motion, and swim as fast (or faster) with a more efficient use of energy because the propulsion is more continuous.

Iím glad you asked about the active drag coefficient (Cd). For a low Cd, it is essential to keep the hips and legs behind their shoulders to minimize the cross-sectional area of the body that is perpendicular to the horizontal direction of body movement. Many swimmers do this well. There are some examples of elite swimmers posted on the STR website: https://swimmingtechnology.com/products/aquanex/aquanexvideo-examples-pull-phase/

For a low Cd, it is also essential to minimize wasted (non-propulsive) force. Each of the elite swimmers have typical, wasted force after the arm entry.
Compare their arm entry with MONAís:
https://swimmingtechnology.com/techn...e-entry-phase/
(MONA is a biomechanical model of optimal technique.)

Ideally, swimmers would only practice with a positive IdC. Realistically, swimmers can always practice with at least a zero IdC (where the arms are in opposition throughout the stroke cycle), even at a very slow (but continuous) stroke rate.
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  #156  
Old 02-01-2017
Zenturtle Zenturtle is offline
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I agree a lot of swimmers are skimming the water surface even with their arm under a slight upward angle and that action is hard to justify.
For minimal frontal area/minimal drag keeping the arm horizontal seems to be best (assuming legs are behind torso in all arm positions).
Getting the optimal compromise going from most streamlined to catch is always a tricky action.
When entering the arm under MONAs angle (20-25 degrees?)you will feel more pressure on the shoulder and the upperarm.
It can only be effective if the arm is angled further without much delay, moving backwards to get rid of the drag on
the arm for the time the arm is moving back slower than the water is moving back, minimising the drag time in the stroke.
My personal guess for the optimal angle would be 5-10 degrees down from the shoulderjoint.

Where are the drag data for towed swimmers with extended arms under different angles?

Last edited by Zenturtle : 02-01-2017 at 02:53 PM.
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  #157  
Old 02-01-2017
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CoachStuartMcDougal CoachStuartMcDougal is offline
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Dear Rod,

You came back to the TI forum ??

You had an entertaining presentation at the USMS Coach Conference. Although when someone says "trust me", that's generally a red flag, but it certainly sparked my curiosity.

What you presented at conference (and in your forum posts) is "conventional wisdom". The notion that the low side arm must always move to prevent deceleration, or using your language, "positive timing good" and "negative timing bad" as something new is just not true. The only thing somewhat unconventional to traditional coaching that we both seem to agree on is spearing lead arm lower, below the lung ball taking pressure off shoulder and re-balancing the vessel. Nothing new here either and what's been taught in TI for years.

Surprisingly (or maybe not) you didn't have anything good to say about Bob Bowman or Total Immersion (Phelps and Yang too) and used to support your argument is another red flag. Using stills without showing the 18 frames before and 18 frames after is misleading and frankly not objective material - not what I consider "scientific", but rather trying to create a narrative and conclusion that seems incomplete.

Deceleration occurs when falling off your edge to a flat position mid-rotation, drag increases triggered by pulling early though rotation. Acceleration occurs when rotation completes on opposite edge and momentum of high side hits its forward extension. That is unconventional thought and is the "Propulsion Paradox" this thread started with about Coach Boomer.

I'm working with an age group sprinter that is at 51 sec 100y free and I expect she will break Simone Manual's 15-16 age group record before turning 17. Trimming the vessel, resist the impulse to pull holding her edge longer, on the cusp of front quadrant timing (or what you characterize as negative timing), primary focus on sending high side arm forward got her to low 50's. The goal is for her to hit a consistent SL 1.27y (15 spl), .60 tempo (100spm) which gets her in the ballpark of 47 secs (not including start/turns so possibly faster).

"It's what happens below the surface that counts". Wish I had a nickle every time I heard that one too. It's both high and low side arms as equal partners with much more emphasis on high side (recovery) arm connected to hips - power from the middle/core, maintaining the shape of the vessel with each stroke. This new focus is very unconventional and beginning to become more understood in the swimming community thanks to Bill Boomer and Terry Laughlin.

Stuart
www.mindbodyandswim.com
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  #158  
Old 02-01-2017
s.sciame s.sciame is offline
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Quote:
Originally Posted by CoachStuartMcDougal View Post
I'm working with an age group sprinter that is at 51 sec 100y free and I expect she will break Simone Manual's 15-16 age group record before turning 17. Trimming the vessel, resist the impulse to pull holding her edge longer, on the cusp of front quadrant timing (or what you characterize as negative timing), primary focus on sending high side arm forward got her to low 50's. The goal is for her to hit a consistent SL 1.27y (15 spl), .60 tempo (100spm) which gets her in the ballpark of 47 secs (not including start/turns so possibly faster).
Wow, it's amazing how at 100spm there's still time to resist the impulse to pull and hold the edge longer!

Salvo
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  #159  
Old 02-02-2017
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Hi Salvo,

Yes - and she's quite fun and amazing to watch. The casual observer would not believe she's hitting 97+ spm, very economical stroke.

She came in with an asymmetrical recovery or high side arm. Left side recovery arm flat with added wrist/elbow movements , arching back - all which triggered right low side arm to pull early for stability and disconnected kick timing every 6 to 8 strokes that resonated through the body like a musician hitting the wrong note.

Corrected the left side recovery and releasing shoulder, now symmetrical with right side (right side recovery already well defined) , minimizing arch in back, high side arm momentum driven forward, and very clean and connected 2 beat kick. Now there's no miss firing of kick timing stabilizing the vessel and she can easily switch between 2,4,and 6 beat kick timing.

Kids, teens pick up new movement patterns so quickly. If I had more time, I'd love to coach age group teams. They haven't been ruined by life's erroneous filters and perceptions that all of us adults have been subject to for so many years :-)

Stuart

Last edited by CoachStuartMcDougal : 02-02-2017 at 05:46 AM.
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  #160  
Old 02-02-2017
Zenturtle Zenturtle is offline
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dont you have before and after TI treatment video?
It would make a change against all those absolute beginner storys.
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