Thread: Shuhari
View Single Post
Old 12-08-2011, 11:53 AM   #19
Walter Martindale
Location: Cambridge, ON
Join Date: Jun 2006
Posts: 704
Re: Shuhari

Kevin Leavitt wrote: View Post are indeed correct! I should have not typed so fast, and having a BS in Biology and Chemistry...I should know better than to use that!

Does it change the argument I present?

Thanks Walter!
I don't think it changes the arguments. I can be anal about some trivial things.

Movement principles are vital.
Qualitative (non-numerical) biomechanics has several. I'll probably forget one or two.

Direction priniciple: movement happens in the direction of the forces being applied and in proportion to the amount of force applied (ok, an equation, F=Ma)
Size priniciple: biggest muscles/joints first, smallest muscles/joints next
Summation of Joint Moments: start the big movements and add the joint moments farther down the chain until the end of the movement. - this is connected to the size principle.
Stability: centre of mass stays within the base. (this can be dynamic)
As I don't use it daily, there's one about angular motion whose name I forget: Spinning objects, bring in the diameter, spin speeds up, put out the diameter, spin slows down... (I'm pretty much a rowing person and if we ever "spin" in rowing, we're in trouble).

All movements in aikido can be explained by physical principles - whether or not we're smart enough to explain them or whether or not we have the technology to measure the physical principles in action is another heap of questions. If we could get a big enough force platform and use 3-d cinematography to do the dynamics computations from force platform up through the mushy humans doing the movements, we could actually compute where the forces that do the throwing come from and explain what "IS" is...

However, a 30 cm x 60 cm force platform by Kistler was $40,000 in 1979 (with all the accompanying signal amplifiers, of course), synchronized camera/computer systems for tracking motion aren't cheap, either, (although the movie industry has some pretty swish stuff) and there ain't money in figuring it out, so I don't suspect it will happen unless someone in a university or big engineering company wants to use the hardware during 'down' time to do a study. (for example, there's a fellow whose paying job is the aerodynamics of wind turbines who uses the software and spare time to model the fluid dynamics of racing oars for rowing)

Once again, I get off topic...
Must get back to work.
  Reply With Quote