you are assuming that swimming is static. When you roll from side to side, as swimming is never done face down in the water that is merely one of th positions that you move through, you present less surface area then if you were laying face down flat in the water. Face down both of your shoulders are in the water. When you are on your side only one shoulder will be in the water.

Long & narrow is more hydrodynamic than long and broad. I'm no physist, but I did make an A in college physics. I also read the paper everyday in that class so there is your disclaimer.

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Brian Stover USAT LII
Accelerate3 Coaching
Insta

Why does the act of rolling change your surface area? I don't see how that's possible. The act of rolling an airplane does not affect its surface area. Also, if you look at pics of dudes like Thorpe and others, their bodies are completely submerged...their shoulders are not out of the water.

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Taco cat spelled backwards is....taco cat.

because when you roll part of your body (shoulder) is in the air part in the water. If you are laying face down both your shoulders are in the water.

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Brian Stover USAT LII
Accelerate3 Coaching
Insta

Maglischo has an interesting discussion about this on the latest edition of his book. As almost always, I would side with him on this one.

OK, I'll buy that. I went and looked at the site you mentioned in the other thread and you can see much of the shoulder out of the water.

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Taco cat spelled backwards is....taco cat.

Rolling is almost entirely a biomechanical issue, not a hydrodynamics issue. You can bring more muscles into play and use them more effectively if roll your shoulders. Just try it on a lat machine with some one arm press downs. You can't help but rotate your working shoulder towards the machine. It makes the lift easier and/or allows you to lift more weight.

However, I believe there is a difference in drag depending on the depth of the object.

I agree.

I actually think we have less drag when closer to flat because we are higher up in the water and have less FRONTAL area that the water "sees." But some rotation is critical to be able to have a shoulder-friendly recovery and to set up a more powerful pull. You don't have to have a lot of rotation to have your shoulder up out of the water. More rotation isn't necessarily going to make it much less. Consider we (I) drop in the water when rotated on side (i.e., I can't kick on side and just swivel my head to air... I'm too low unless I wear fins to keep speed way up).

Another doubt I have about more than minimal rotation is that I do not think the hips have any role other than to provide a stable platform for the kick. Many many many more qualified people will strongly disagree w/ me on that one.

I swam five 200s last night using different amounts of rotation and hip action. Of course, I'm slow and it's impossible to put in exactly the same effort and the number of tests was small, so it may not be worth anything. The more hip action/rotation I used, the slower I was. Flattest = fastest. The diff was about 7 seconds. Interestingly enough, when I tried it with a snorkel, I was slowest of all, nearly 10 secs off the flattest.

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When you watch fast swimmers now they rotate much more from the hip and not from the shoulder. The recovery shoulder clears the water while the extended arm is at or near the surface. The shoulder will move forward not down.

Water flows under the extended arm, under your chest, past yor thighs and finally (if your toes are pointed) past your feet.

Your hips lead the power surge while your extended arm is holding onto the water with your finger tips to forearm forming a straight line pointing downwards and your elbow pointing forward.

DougStern

"When you watch fast swimmers now they rotate much more from the hip and not from the shoulder." Yes, just to be clear, that does not mean they rotate more AT the hips and not AT the shoulder. I think many of us confused that for awhile.

"The shoulder will move forward not down." Not sure what you mean by that, but the recovering shoulder most definitely moves down in the water as recovery ends and the hand hits the water, and rotation begins to the other side.

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Aztec,

Your hips should roll much more than your shoulders. Your shoulders actually do not roll they alternately move forward (with a little drop) and then up. On recovery they lift and clear the water.

DougStrn

I dunno, Doug. I have pretty reasonable flexibility, and my hips don't have much ability to turn independent of my shoulders. If I stand up, reach overhead and then try to turn my hips, my shoulders are coming along for most of the ride. It's that whole "roll as one unit, like a log" thing.

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The best way to think of hip rotation in freestyle is to do the following:

1. Stand in front of a wall, facing the wall.

2. Put your left arm in the air above your head. The other arm can be at your side. You are pretending the wall represents the bottom of the pool.

3. See how far you can reach while keeping your entire torso parallel to the wall, no rotation.

4. Now hold that position and rotate your left hip towards the wall. You are probably able to reach another 4-12 inches by doing this. Notice that the vast majority of the rotation actually came from your hips.

4-12 inches? Seriously? I just tried it, and it's maybe an inch or two. And no, the amount of rotation was equal at shoulders and hips. To have the hips turn more would mean a twist of the spine, which would not lengthen the axis (technically, it shortens it).

I'm trying not to sound argumentative, but it doesn't make sense that your hips could or would turn more than your shoulders. You would be twisted and if swimming, having a tougher time staying in a straight line.

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Great imagery...I finally see why hip rotation is improtant to the stroke rather than the "hydrodynamics". Great stuff.

Here is what I've observed...Twisting from the hips while reaching above your head with one arm will actually lengthen your spine. In order to reach you highest point your spine twists, which lengthens it a little. If you reach without twisting your spine curves which does shorten it or reduces its length potential. saying another way I think twisting reduces the bend in your spine, keeping it straighter.

while I am swimming I think about "Reach and Roll" (thanks Andrea Fischer!). This serves a few purposes. One, as said above, I believe it lengthens my body which allows me to go faster in the water. The longer the object the more hydrodynamic. Two, it allows the recovering shoulder to exit the water, which reduces what the amount of me the water sees. Three, as I start the pull, the act of rotating the recovering arm and shoulder forward to the reach, allows me to incorporate more muscles, lats and deltoids, into my stroke.

My roll starts from my hips based on timing of my kick. My hips roll to maybe 45*, my shoulders more but not 90.

That is a good way to describe it. I get the image of reaching for something on a high shelf. When I reach for something up high I will always move my hip towards the object to get more a little more length in my reach.

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"And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country" JFK - Replace 'country' with the company you work for, friends, family, and strangers and the world will be a much better place.

The mistaken notion is that the water flow under you. It is not a gas. It has to flow around you. flowing around the width of the chest (and shoulders) is a long, wide, slow path. A little rotation makes the path shorter and straighter.

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Dick

Take everything I say with a grain of salt. I know nothing.

We don't know. None of us have ever seen real data showing that you have less drag on your side than when flat. We have our suspicions, but we don't have real data because the studies have never been done.

The swimming motion is terribly complex, you've got the rotation side to side, arm motions that vary greatly from one swimmer to another. Arm entry that varies form one swimmer to the next.

In spite of all that, everyone else mouthed off like they know, and so will I ! :-)

WAVE DRAG

Yes wave drag, wave drag just beats the pans off of from drag any day. It also increases with the cube of velocity, where form drag only increases with the square.

Wave drag is related to the fact that above poster mentioned where at the surface of the water, the water prefers to go around you than under you or over you. This interface is in fact different than an airplane which is fully immersed in its fluid.

So, flat shapes make larger waves, thin shapes make smaller waves. And that, in my opinion, is that.

I agree with Flanagan. One of the dry drills that we do is pretty much what he described. We call it the crab drill and it is reaching with the arm, rotating the hip and trying to keep the shoulders as "flat" as possible. Not that you don't want them to turn a bit, but the majority of the rotation comes from the hips.

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http://bigisland-will.blogspot.com/

I aint' buyin' it!

:-)

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Too f@ckin depressed from various injuries to care about having a signature line.

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If anything, the hips rotate and the shoulders move sort of forward and closer to the centerline of the body. A coach for Curl-Burke out here in VA told me I am a poster boy for TI swimming, because I am a front quadrant guy, although I had never heard of TI until a year ago and it has nothing to do with why I swim the way I do. I definitely notice any beard or stubble rubbing against my shoulder as I extend out in the front quadrant. I see this as evidence of the shoulder moving more forward and towards the centerline of the body.

Aztec, if you want to become a better swimmer, it might help to listen to good swimmers/coaches so you can learn what to do as opposed to constantly trying to disagree with what they are saying regarding freestyle stroke mechanics. Maybe the fact that you can only get an extra inch (doing the "face the wall" exercise) means you need to work on flexibility and hip rotation.

You do have less drag when rotated on the side. Docfuel touched on it, but it looked like no one noticed. Water molecules flow around you rather than under you. Pressure increases as you go deeper and the molecules will follow the path of least resistance, ei sideways/around your body, rather than under it. So when you're on your side, there is less distance to travel horizontally before they're around your body (work = force x distance). The data is in ship building/boat building. If a flat surface area were ideal, why are all ships/boats that are built for speed built with more depth and less width than the other way around? Why do barges go so slowly? (And don't bring up hydroplanes, they aren't technically in the water).

Not sure that example holds. A ship presents much less frontal area than a barge...it is much more streamlined. The human body is the human body no matter what position it is in.

Just thought of something else...if your example were true...why aren't submarines tall and skinny?

Spot

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Taco cat spelled backwards is....taco cat.

Some people here are completely missing the poing of the way freestyle works. During the catch of the left arm, the right arm is out of the water in the recovery phase. Most of the right shoulder is out of the water. The left shoulder at the same time is rotated forward and towards the centerline of the body. This movement of the left shoulder allows you the swimmer to engage the larger muscle groups of the back to begin the pull; however, this position is much more hydrodynamic due to a much smaller frontal area.

Stretch your arm right out in front of you now, so your shoulder touches part of your jaw/chin. Notice how much the edge of your shoulder has moved to the centerline of the body. This change in position is what enables you to acheive a move hydrodynamic position. Hydrodyanamic improvements are not the principle reasons for rotation, rather they are byproducts of rotation.