How does weight shift cause propulsion?

[kalinma]

Originally Posted by CoachKevin

That's right, borate. That's the Kinetic Chain I mentioned before - kick... then rotate... then lengthen. The rotating body doesn't - can't, really - propel itself, but in conjunction with the correctly timed kick & lengthening movements propulsion happens. And timing is everything. A swimmer can do all 3 things correctly, but done with the wrong timing it doesn't work, at least not as well as it could. We taught 1000's of people to just rotate & lengthen before we started to teach (2 beat) kick timing back around 2004 or so.

Thanks for this point, Coach Kevin. So how does one achieve the elusive timing? I suppose it's just like everything else--devoting time and attention to it and being patient with oneself.

[CharlesCouturier]

Originally Posted by Lawrence

Worth remembering also that what comes down must first be lifted up. So, however weight shifts are used to aid propulsion, the relevant weight must first be raised, and that takes muscular effort.

There's a cyclic/recycling effect here...

I've often described weight shifts in my own words to my athletes applied to freestyle swimming as sinking the head of an opponent with your leading hand, then rolling on him and propel yourself forward til your next hand sinks another opponent etc... Quite honestly, I'm not sure everyone could really understand this analogy, until Harry Wiltshire *finally* performed his magical move, pertaining to this explanation.

Picture is worth a thousand words:
https://www.youtube.com/watch?v=p1wnu0xzvjo

So, at one point in the clip, Harry puts his whole body weight on the downward body rotation to swim over Javier Gomez. The thing that's fun to see is what comes after. His next stroke is done exactly the same manner. And in fact, when you look at several other swimmers in this clip (ie pro folks), you often have the impression that it's as if they too were sinking opponents on catch.

Originally Posted by Lawrence

If one swam perfectly flat, of course, including spearing horizontally and executing the catch without first having to move the forearm from horizontal to vertical, then there would be no weight shifts to discuss.

Sure, and I'd say that some feel their freestyle this way. Flat, no weight shifts.

Originally Posted by Lawrence

Those that there are exist because we use our muscles to create them. I think the 'free' forces Terry is talking about are the weight drops which such muscular action allows us to play with.

It doesn't take much muscle effort to achieve the body rotation, which is the main force around which weight shifts are being created and managed by the swimmer.

Here's a simple drill that involves a swimmer wearing a pull buoy (no propulsion from the kick) as well as not using his arms to stroke. The propulsion in this case then is function of body rotation generating weight shifts which I believe are being transferred to the hand (which does a gentle sculling action). It introduces the notion of recycling here. That sculling creates support whilst the body rotates upward.

https://www.youtube.com/watch?v=bHSYQ6BaM2A

In other words, just to get things straight. If this swimmer was flat on his belly, the propulsion then would rather be created by a dedicated muscular effort from the triceps muscles. Body rotation in this case allows for those triceps muscles to work less. That's the idea.

Underwater view:
https://www.youtube.com/watch?v=8n_rqKsqU_w

Note, and it's a crucial element for success in this drill, the hips move first, then the power is being transferred back to the pushing hand. Hips first, all the time. They clearly move up or down (depending on the hip you're looking at) by themselves, without any noticeable support from the hand.

Originally Posted by Lawrence

Terry's insight here is unquestionable, I think, namely that weight shifts if used in a certain way can aid efficiency. The question is how that happens.

Not sure anyone can claim having all the answers to this question unfortunately. It could take a while for science to explain everything.

But from my swimmer's perspective (not even a coach perspective), for me, swimming on a pace that's faster than 1:20/100 for a whilst requires that I put my body weight on the catch (sinking the head of an opponent), then rolling over him quite aggressively until I sink my next victim. Without that, I can't be fast.

[andyinnorway]

Charles, I am really enjoying your perspective on different matters.

For clarity are you saying to imagine pushing my enemies head down and then nearly pull him backwards with my fingers in his nostrels?

This beautiful analogy might help me succeed in the killer end to my consolidation set today.

[CharlesCouturier]

Originally Posted by andyinnorway

For clarity are you saying to imagine pushing my enemies head down and then nearly pull him backwards with my fingers in his nostrels?

Exactly! Kidding... No, sink them first, then whilst pulling grab their bathing suit and propel yourself over their body. Nostrils could work just as fine, as long as they provide you with a solid anchor point.

I'm dragging behind in this regard Andy, it I was very pleased to notice this when I first started crawling on this TI forum.

The whole story is simple. I've never thought that it's possible to swim fast, for prolonged distances, without relying on weight shifts. Even those who deny their existence in my opinion, use them. I'd never actually studied them myself though. So it's something I feel.

The best analogy I could come up with was that one (that got you to smile). That was then, but now thanks to Harry, I can more easily make my point LOL

Now tbh it had never occurred to me that I shall teach this to slow swimmers though. In my book, they can learn without this. Now I realize that it's a big thing in Total Immersion's method, very early in anyone's development. I still have no take on that.

Originally Posted by andyinnorway

This beautiful analogy might help me succeed in the killer end to my consolidation set today.

Kill em all mate! (not very mindful, sorry LOL)

Originally Posted by andyinnorway

I am really enjoying your perspective on different matters.

I'm glad if I can sometimes be a breath of fresh air, I'm not asking for any more.

That said though, it's really worth noting that I'm dragging behind in this area imo, not in term of my own ability to apply these principles but rather in my ability to teach it through an organized drills progression. I could refer to my (proud) Sweet Rotation drill which indirectly addresses this somewhat, but that's about it. Can't do any better to organize a process that would lead toward mastering this. Aaahhhhh, swimming. So mysterious. How can we get bored, impossible!

Also, it could be that my use and definition of weight shifts probably differ from that of TI.

So I'm glad if I can put some smiles on some faces, but your TI Coaches remain the best resources to guide you through this.

[truth1ness]

Originally Posted by borate

A recent PBS NOVA program featured a segment on the properties of bodies propelling through two liquids.
In an image taken straight from your high school biology class, the tail of a sperm-like creature oscillated up and down with vigor as it swam through plain water.

Their experiment proved that as the liquid became more viscous an up/down tail movement would not be sufficient to generate propulsion. Dead in the water.
Yet this microscopic creature continued to advance through that medium. How could that be?

When the sperm-like body was viewed at higher magnification the answer became apparent. The tail was not oscillating up and down. It was a corkscrew!
And that strikes me intuitively as the reason behind the forward momentum being discussed here...

Rather than dissecting the elements of the stroke, envision them as acting SYNERGISTICALLY. Correctly timed, it's a beautiful thing...
The kick/hip drive twists the body at nearly the same moment as the arms spear and pull respectively. This may 'screw' the body forward.

Wow, this corkscrew idea really helped me. My spl was jumping up and down from 15-20 and couldn't figure out why, but when I really focused on moving my body on a corscrew motion I'm getting consistent 14s and 15s now. Really eased pressure on my shoulder, too.

On the other hand, thanks to you I will always have the image of a sperm in my mind when I swim. :\

[CoachGaryF]

I'm more inclined to go with something closer to Terry's original answer. Not because he's Terry, but because I think there are other weight shift = forward momentum models to look at. Weight shifting certainly contributes to forward movement in all of the skating sports.

The question is: at what point in the movement pattern is forward movement created? I submit that it's the moment when the recovering limb moves just forward of the anchoring limb. At that point you get two elements helping to propel you forward 1) Gravity, as you are just about mid point in the weigh shift, or the tipping point where you actually SHIFT to the other side 2) Vaulting forward off of the anchor.

In swimming, this midpoint or tipping point is the moment when you are in a flat belly position. You don't STOP there, of course, but picture stealing a still frame at that moment. Your spearing arm (the "high side") is forward of your head and probably half submerged. Your anchoring arm is probably slightly forward or equal to your shoulder. In other words, your weight is just about ready to shift over to your spearing side from your stroking side. That also equals the first moment in the stroking phase that you can actually leverage effectively. In essence, your body is falling onto the new side at the same moment you're finally able to vault off of the stroking arm. Without a weight shift you'd be stuck trying to create velocity through pushing only. Not very effective. I personally feel that weight shift is the dominant movement in my stroke. I barely pay attention to or worry about my hips at all, and when I do the result is nearly always crazy over rotation. Timing spear, weight shift and, for lack of a better term, VAULT strikes me as the real heart of creating forward movement. At least for me.

I don't skate, rollerblade or ski, and can barely run. For those of you who do these sports, is there a trigger point that serves as the launching pad for forward movement?

(If you look at Shinji's top video, pause it just a few frames into the :52 second mark. You'll see him in a belly down position, left arm in mid-spear, right arm anchor equal to his shoulder. That's the trigger or tipping point I was trying to explain.) I would upload my own image but not sure how to do that here.

Gary

[CoachGaryF]

I also think you have to have both elements--anchor and weight shift--for this to work. A weight shift that isn't tethered to an anchor won't do squat. (For those inclined to speak in hip-centric language, hip drive in isolation will make you rotate but it won't make you move forward.) And a pull or push without a weight shift gets you a little something, but not much.

[andyinnorway]

Originally Posted by CoachGaryF

I also think you have to have both elements--anchor and weight shift--for this to work. A weight shift that isn't tethered to an anchor won't do squat. (For those inclined to speak in hip-centric language, hip drive in isolation will make you rotate but it won't make you move forward.) And a pull or push without a weight shift gets you a little something, but not much.

Gary I think this is excellent explanation. Thank you.

[CharlesCouturier]

Originally Posted by CoachGaryF

I submit that it's the moment when the recovering limb moves just forward of the anchoring limb. At that point you get two elements helping to propel you forward 1) Gravity, as you are just about mid point in the weigh shift, or the tipping point where you actually SHIFT to the other side 2) Vaulting forward off of the anchor.

Therefore you don't think it's possible to use body weight in favor of propulsion whilst say... executing the single arm drill for instance?

[CoachGaryF]

Charles,

With regard to the single arm drill (I think you mean the one where you keep the non-stroking arm resting at your side), I would say that is essentially correct. I think the primary "weight" in the weight shift isn't the torso; it's the recovery arm that is above the surface.

Consider how you experience weight shifting in Spear Switch drill versus Swing Switch or whole stroke swimming. It's clear to me that Swing Switches and whole stroke freestyle have profoundly more powerful weight shifts. I think that's because you are REALLY taking advantage of gravity when the weight of your arm is above (even partially above) the surface. As that arm falls into the spearing movement you have significant gravitational forces at work. Much more dynamic than a spearing arm that is below the surface.

In the single arm drill you will have this dynamic shift only half of the time, when the single arm is airborne and dropping into the water. You'll "fall" rather quickly. But not on the return rotation, the "torso-only" one, when the single arm is stroking below the surface. You don't "fall" fast enough because there isn't much weigh to work with. I once heard Richard Quick (RIP), the former Stanford & US Olympic coach, describe freestyle as a "high side DOWN" stroke. He meant the high side (torso & recovery arm) falling into the water is the key driver. In single arm drill that key driver is available half of the time. There IS no high side for the other half of your rotations, unless you consider a little bit of shoulder poking above the surface as "high." It's profoundly unbalanced and significantly divorced from what's experienced in whole stroke swimming. Maybe so far divorced as to be unhelpful to all but the most advanced of swimmers.

Try doing head lead body rotations with both arms at your side. Difficult to do quickly or sharply unless you use your kick to drive the rotation (which could be a good drill for connecting 2 beat kick & core rotation.) Otherwise you just kind of drift over from one side to the other, like a manatee rolling around. Why? Because a mostly submerged torso (except for a bit of shoulder poking above the surface) doesn't offer much weight for the gravity gods to act upon. You could snap your hips to quicken the rotation, but I think that means using them in a way that you would not when you are actually swimming.

Is there some value to the single arm drill? I suppose there is. But that drill is very difficult to get right, the upside is both elusive and in my opinion quite small, and most people would do well to spend their limited swimming minutes on something more productive. I mostly think of single arm swimming drills in the way that a running coach might consider single leg running drills, or a skating coach would employ single blade skating drills. I doubt they use them much. I don't mean to be a contrarian. That's just my take.

Gary