General Discussion Triathlon Talk » Analyzing the Underwater Pull Rss Feed  
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2011-12-05 5:47 PM

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Subject: Analyzing the Underwater Pull

How we use our hand/forearm to create power and lift in swimming has been the subject of much controversy. In the video series below, I am trying to make sense out of a complicated motion. We have posted 3 videos and articles so far on the subject with two more to go in the next few weeks.  The series is divided into the following five videos: introduction, lift phase, front quadrant propulsion, back quadrant propulsion and release phase. Hope you enjoy.

 

http://www.theraceclub.net/videos/underwater-pull-series-introduction/

http://www.theraceclub.net/videos/underwater-pull-series-lift/

http://www.theraceclub.net/videos/underwater-pull-series-phase-ii/

Yours in swimming,

 

Gary Sr.



2011-12-05 6:00 PM
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2011-12-05 7:38 PM
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Champion
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Subject: RE: Analyzing the Underwater Pull
Fred D - 2011-12-05 7:00 PM

I would just like to sat thank you Dr. Hall, I always learn from your posts!!

x2!  I look forward to the future videos.

2011-12-05 7:44 PM
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Regular
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Tucson, AZ
Subject: RE: Analyzing the Underwater Pull
Thanks for posting!!  Btw you can add some hyperlinks easily by clicking on the chain symbol in the rich text editor.
2011-12-05 7:51 PM
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Pro
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The Land of Ice and Snow
Subject: RE: Analyzing the Underwater Pull

Timely thread  

Thanks.

I was just talking to a swim coach ( not mine, he just happened  to watch me swim today) about the pull portion of the swim today.

He told me not to pay much attention to it, but just to keep trying to decrease my stroke count in order to improve my swimming.

I am not so sure that he is on the money......

I remember you telling me (you once watched my pathetic swim video) to increase my stroke count. And I have been reading about the benefits of an increased stroke count as well.

I think the money, for me anyway, is the pull. 

 

I have had a professional underwater photographer offer to shoot a video of me in the New Year. We shall see how that turns out.

I will probably post it here in order to give everyone  good giggle......I have no pride.

2011-12-05 7:53 PM
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Pro
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Subject: RE: Analyzing the Underwater Pull


2011-12-05 9:23 PM
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Champion
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Subject: RE: Analyzing the Underwater Pull
GREAT information! Thanks!!!

2011-12-05 10:56 PM
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Master
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Subject: RE: Analyzing the Underwater Pull
Very nice!
2011-12-06 4:38 AM
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Elite
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Subject: RE: Analyzing the Underwater Pull

Nice videos, thanks.

During the lift phase, would that not be highly dependent on the  shape and position of the arm for it to actually generate any lift?  If so, what is the ideal position?

2011-12-06 9:18 AM
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Expert
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Subject: RE: Analyzing the Underwater Pull
2011-12-06 9:37 AM
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Subject: RE: Analyzing the Underwater Pull
Very helpful videos.  Thanks Gary.  The big question, though, seems to go unanswered.  Which is the best pull technique for triathletes?  I'm thinking it is the shoulder-driven technique, since I've always been told to save the legs for the bike and run.  On the other hand, the longer the race the more important hip and body rotation seems to be, which is key to the hip-driven technique. 


2011-12-06 12:19 PM
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Lost in the Evergreens
Subject: RE: Analyzing the Underwater Pull

After watching the videos lastnight, 3 to 4 times each, I took the fresh mental pictures to the pool with me this morning.  The images of the circle (simplified) translates well into a sense of how the underwater pull should feel.

I get the lift concept but 3 tenths of a second is not much time to get in a decent arm extension.  Should I be thinking arm diving down into the circle catching with the forearm, rather than reaching out and catching with the hand before the pull?

One other comment with respect, loose the cap in the first video.  The shadows across your face are distracting and make it difficult to focus on your message. 

Thank you very much for details you provided.  Very well done presentation with outstanding production quality. The acceleration measurements are very convincing. 

Best Regards,
Mark

2011-12-06 1:05 PM
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Pro
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Subject: RE: Analyzing the Underwater Pull

as alway, your input is much appreciated!

Thanks for the hyperlinks Aquagirl!

2011-12-06 1:49 PM
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Master
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Rio Rancho, NM
Subject: RE: Analyzing the Underwater Pull

Great videos! I'm working on my swim speed this winter so this will be great info to take to the pool.

2011-12-06 2:31 PM
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Coach
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Stairway to Seven
Subject: RE: Analyzing the Underwater Pull
Gary, I watched one of your other videos (maybe it was part of this series, not sure) where you showed in a video the path of the hand of an elite swimmer, which exited the water right where it entered...therefore the average speed of the hand was ZERO during the stroke. This graphic made it pretty clear how and why the REST of the arm is creating drag, and how cautious and careful one must be when placing the arm into the propulsive position so as not to cause a loss of momentum.

As I've been practicing with these ideas in mind, it really feels like I'm paddling a fast boat, whtih the amount of force required to maintain speed much lower than what I was exerience before...and yet I'm traveling the speed or faster. So these ideas definately work.

However I wanted to caution people from a medical point of view (yes I know you are physician). It seems like you are using the term "lift" in a different way than most swim literature has traditionally used it. "lift" in swimming has traditionally referred to a forward propulsive component caused by the hand moving through the water with some element of sideways movement, as if the hand were an airplane wing oriented vertically and moving sideways in the water. However Computational Fluid Dynamic studies have shown this component to be so negligible as to be nearly non-existant. In addition, some studies suggested that the Bernoulli effect doesn't even happen in the water due to the boundary layer interaction creating turbulent, rather than laminar flow around the swimmer. (Laminar flow is required to create lift)

So when you describe "lift" you are referring to a literal upwards (toward the sky) lifting of the body, which is created more due to angle of a attack of the leading arm and simple "action, reaction" forces. push down on the water and the body goes up rather than Lift in the sense that an airfoil creates lift.

I think adult triathlete swimmers need to be extremely cautious about this front quadrant movement in swimming because pushing down in front usually causes the rear to sink. Since avoiding drag is the #1 consideration in swimming, you need to be a fairly well conditioned swimmer for this to work. You need to have strong shoulders since this is an unstable position for the shoulder, a strong core that won't collapse, and a strong sense for what it feels like to remain balanced in the water (can you sense when your hips sink, even just an inch).

In order to progress towards what Gary is describing, most triathletes looking to get faster should be very careful to protect the shoulders in this phase, not push down. Instead focus on the streamline and "free speed" available here by not letting the hips sink, while the body rotates and drops the forearm into the catch position ready for the next phase of propulsive effort (which is a push, not a pull)

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