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  1. Keslet is offline

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    Posted On:
    9/30/2013 7:25pm


     Style: Wrestle, Kickbox, Aikido

    --
    Hell yeah! Hell no!
    Quote Originally Posted by ChenPengFi View Post
    The point i'm trying to make is you're bound to need to oversimplify, making the whole exercise somewhat questionable.
    Juji-gatame is just as problematic as Krijgsman's post illustrates, as does JudokaUK's article on straightening the arm:

    http://thedifficultway.blogspot.com/...tame-from.html



    No problem visualizing THAT now, thank you ChenPengFi! Damn! Okay, so in that example, the shoulder is mostly static (despite her best efforts I would bet), and there is clearly force being applied by the hips at the elbow (upward) and by the upper body at the end of the arm (downward)...so is that what makes it a class 3 lever? That seems to be in line with the explanation I found...I just never thought of it in that way.

    Again, I know my questions are probably basic/stupid, but I do appreciate folks helping to clarify. Thanks for taking the time!
  2. Dr_Awesome is offline

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    Posted On:
    9/30/2013 8:02pm


     Style: Hapkido

    --
    Hell yeah! Hell no!
    Ok. So I had to sit down and think through juji-gatame, because something just felt wrong to me. So I threw together some quick shape drawings to help.

    I am fully aware that I just drew an able bodied dude putting a guy with only one arm and no legs in an arm bar, which really isn't nice of him, but I wanted to keep it simple.

    So the fulcrum would be the purple dude's shoulder, the applied force is the blue dude's hips, and the load is the blue dude's upper body, attached at the purple dude's wrist. The elbow corresponds to none of those points, it just happens to be the spot where the lever breaks most easily.

    I originally treated it like the force was being applied at the wrist, but I should have known better than that. A good arm bar means you hold the wrist tight (but do not actively pull it down) and push up with your hips, not the other way around...

    Since the applied force is much closer to the fulcrum than the load, you actually give up force in exchange for more distance with this technique, and since the upper body isn't going anywhere, more distance = more dislocation at the elbow. This is interesting, because it seems a little counterintuitive at first, and it means the elbow will break with much less applied force than I originally thought...
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  3. ChenPengFi is offline
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    Posted On:
    9/30/2013 10:00pm

    Join us... or die
     Style: Hung Gar, Choy Lay Fut

    1
    Hell yeah! Hell no!
    So again, simple machines are inadequate.

    I'll just leave this here for now:
  4. Keslet is offline

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    Posted On:
    9/30/2013 10:04pm


     Style: Wrestle, Kickbox, Aikido

    --
    Hell yeah! Hell no!
    Quote Originally Posted by Dr_Awesome View Post
    Ok. So I had to sit down and think through juji-gatame, because something just felt wrong to me. So I threw together some quick shape drawings to help.

    I am fully aware that I just drew an able bodied dude putting a guy with only one arm and no legs in an arm bar, which really isn't nice of him, but I wanted to keep it simple.

    So the fulcrum would be the purple dude's shoulder, the applied force is the blue dude's hips, and the load is the blue dude's upper body, attached at the purple dude's wrist. The elbow corresponds to none of those points, it just happens to be the spot where the lever breaks most easily.

    I originally treated it like the force was being applied at the wrist, but I should have known better than that. A good arm bar means you hold the wrist tight (but do not actively pull it down) and push up with your hips, not the other way around...

    Since the applied force is much closer to the fulcrum than the load, you actually give up force in exchange for more distance with this technique, and since the upper body isn't going anywhere, more distance = more dislocation at the elbow. This is interesting, because it seems a little counterintuitive at first, and it means the elbow will break with much less applied force than I originally thought...
    Which part felt wrong to you before? This seems to be pretty much what CPF was saying, I think...load at wrist, hips applying force, fulcrum at shoulder...the picture posted at an example looks to have the hips pressing up pretty much at the elbow, but as long as it's in between the fulcrum and the elbow it shouldn't matter, correct? I realize I've been mixing up terms, but what you drew is pretty much how I'm picturing it now...
  5. ChenPengFi is offline
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    Posted On:
    9/30/2013 10:12pm

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     Style: Hung Gar, Choy Lay Fut

    1
    Hell yeah! Hell no!
    Quote Originally Posted by Keslet View Post
    Which part felt wrong to you before? This seems to be pretty much what CPF was saying, I think...load at wrist, hips applying force, fulcrum at shoulder...the picture posted at an example looks to have the hips pressing up pretty much at the elbow, but as long as it's in between the fulcrum and the elbow it shouldn't matter, correct? I realize I've been mixing up terms, but what you drew is pretty much how I'm picturing it now...
    I was actually visualizing the fulcrum at the wrist, but it's a *really poor analogy* anyhow.
    The gear puller is much better.

    Hint:
  6. Dr_Awesome is offline

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    Posted On:
    9/30/2013 10:28pm


     Style: Hapkido

    --
    Hell yeah! Hell no!
    Quote Originally Posted by ChenPengFi View Post
    So again, simple machines are inadequate.
    Yea, I cannot and will not argue with that statement.

    I was, however, hoping to find one or two scenarios simple enough to make a good example.

    Perhaps the hands behind the head in a muay thai clinch... low hands behind the neck vs higher up behind the head.
  7. Keslet is offline

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    Posted On:
    9/30/2013 10:43pm


     Style: Wrestle, Kickbox, Aikido

    1
    Hell yeah! Hell no!
    Quote Originally Posted by ChenPengFi View Post
    I was actually visualizing the fulcrum at the wrist, but it's a *really poor analogy* anyhow.
    The gear puller is much better.

    Hint:

    The fulcrum was at the wrist?

    Well, FWIW, thank you all for the discussion, I do believe I learned something new from it, which is one of my main criteria for having a good day! Good Night Gentlemen!
  8. Dr_Awesome is offline

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    Posted On:
    9/30/2013 10:56pm


     Style: Hapkido

    --
    Hell yeah! Hell no!
    Quote Originally Posted by ChenPengFi View Post
    I was actually visualizing the fulcrum at the wrist, but it's a *really poor analogy* anyhow.
    The gear puller is much better.

    Hint:
    yea, that picture makes it tough to picture as a lever. He's obviously got his back arching on one side, and pulling his legs back on the other, which means he's applying force on both sides of the elbow.
    Last edited by Dr_Awesome; 9/30/2013 11:00pm at .
  9. ChenPengFi is offline
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    Posted On:
    10/01/2013 3:18am

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     Style: Hung Gar, Choy Lay Fut

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    Hell yeah! Hell no!
    Damn, you're earnest...

    The problem is your "question" is wrong.
  10. Dr_Awesome is offline

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    Posted On:
    10/01/2013 8:17am


     Style: Hapkido

    --
    Hell yeah! Hell no!
    Quote Originally Posted by ChenPengFi View Post
    Damn, you're earnest...

    The problem is your "question" is wrong.
    Yes, but is is always wrong, or just almost always wrong?

    I would be content with "almost always", if we can figure out one or two scenarios where a lever actually is a sufficient description.

    Thanks for all the discussion on this, by the way. This is fun.
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