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I Is it physics or flexibility?

  1. Aug 1, 2017 #1

    Who can explain this video? It must be because the people in the video have smaller backsides/hips so their center of mass would be above their ankles and then their arms are providing the extra torque... Or just stretched out ankles?
    The moderator is taller than everyone else in the video I think that is why he can't do it either... As in not a ankle stretching thing but a center of mass/torque thing.

    Either way my knees hurt now after 20 minutes of falling backwards.
  2. jcsd
  3. Aug 1, 2017 #2


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    Gold Member

    Nothing to it.
    On the first try.
  4. Aug 1, 2017 #3


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    2017 Award

    I have always had a problem doing this. I have tried to figure out he problem. I conclude that it is partly due to relative lengths of leg joints and lower body mass. Short lower leg and long upper leg will put your CM way back beyond your heels (particularly if your body CM is low). My ankles are very tight and that limits how low an angle I can get my shins, too. Also, I have 'big' thigh muscles and 'big' calf muscles so I can't fold my legs together as the people in the video were doing.
    I guess there will be many sources of anthropometric data across the racial types. That could resolve the matter. I must find a spare hour to search . . . .

    I have achieved the pose when carrying a heavy back pack (raised CM). That surprised me at the time. But my joints soon started hurting.
  5. Aug 1, 2017 #4


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    Personally, I think it is entirely a cultural thing. If you are raised to do this from the time you can walk, it's nothing special. It is done in Asia and other parts of the world and not here in the US
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