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Old 01-25-2013, 01:30 PM   #27
ChrisHein
 
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Dojo: Aikido of Fresno
Location: Fresno , CA
Join Date: Apr 2005
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Re: A simple mechanical model of body use.

Quote:
Phi Truong wrote: View Post
Hunter has provided lots of good info for the discussion. most folks when they picked up something they are thinking of pulling it up, especially something light. internal folks train to get underneath and push it up, even with a feather. and we already talked about efficiency on the other thread.
The first problem I see here is that- muscles only contract. So every motion is really a 'pulling up' because it's a contraction. The muscles can't 'push' anything, they all contract, and make the body do different things because of their orientation in the body. So triceps seem to be making the arm 'push out' but really they are pulling on the backside of the arm to make the arm extend. Muscles work in opposing sets like this so we can get action on both sides of the body. We both are fully aware of this I'm sure, but I have to say this to make my next point.

If you use one set of muscles to support or lift a load, they are pulling. you can use an opposing set of muscles to pull in the opposite direction at the same time ('dynamic tension'). But you don't get a bonus result for this, you only expend more energy. Muscles can't help each other by using a complimentary 'push and pull' or 'extend and contract', they can only contract or 'pull'. So if you activate opposing muscle groups you are only costing energy and not gaining it.

Now this is not to say that the 'imagery' of pushing with one set of muscles while pulling with another set isn't helpful. But that can't be what is actually happening. Imagery is very useful in training physical motion. I often use images of rushing water, or electricity going through the body to help my students move correctly. But of course we know there is no water or electricity rushing through the body.

Quote:
here is an exercise that Sigman got us to do. stand normally with feet parallel about shoulder width. take a small weight, less than 1 kg. hold it in between your palms and raise it with arms straight, straight up the top of your head. hold it there. now relax your body and let the weight pushes down to your feet so that you will only feel the weight pressure on your palms and the bottom of your feet. you should feel like you are now holding the weight by pushing from underneath (pushing isn't the right word to use here, but for simplicity, i am using it). hold it there for awhile and try to let go off your shoulder muscles.

now, drop your arms (still straight out) 45 degree from vertical. the weight should be infront of you and above your shoulders. don't move the rest of your body, but use your intent to adjust your body so that you still pushing it from underneath and there would still be pressure between the palms and the bottom of your feet, i.e. your body doesn't exist, only palms and feet. then drop your arms to 90 degree from vertical. do the same thing as before. allow your body to adjust. then drop to 135 degree from vertical. then 180 from vertical which at this point the weight should be around your crotch. and you are still pushing from underneath. it should feel like you are pushing the thing up with your feet. this is bringing the ground to the object or a simple model of ground path. experts will tell you that there are more it than that and they are right. because your focus is pushing from underneath, your body will microscopically adjust internally to use the blue line (don't think of line but tubes) that Hunter mentioned.
This is a fun exercise, I plan to work with it today, thanks!

Quote:
i can provide a video but you would only see my good looking self stand there not doing much. i might eat a donut or two with coffee.
I think more of us good looking people should be posting videos. We'll help Jun get more subscribers that way!

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