OKC - CKC

[Guest guest]

Tom Rankin wrote:

> You may be reading too much into Steidler's definition. Which you

> generously supplied as:

>

> " We designate an open kinetic chain a combination in which the

> terminal joint is free. The waving of the hand is an open

> kinetic chain in which the action of the shoulder joint, the elbow

> joint, and the wrist joint are successively involved.

>

> A closed kinetic chain, on the other hand, is one in which the

> terminal joint meets with some considerable external resistance

> which prohibits or restrains it free motion. Eventually, the

> external resistance may be overcome and the peripheral portion of

> the joint may move against this resistance, for instance, in

> pushing a cart or lifting a load; or the external resistance is

> absolute, in which case the proximal part moves against the

> peripheral, as for instance, in chinning oneself on a horizontal

> bar; or the limitations of the muscular effort may assert itself

> both peripherally and proximally and may be unsurmountable, in

> which case no visible motion is produced. Only in the latter

> instance is the kinetic chain strictly and absolutely closed.

> However in common use we apply the term to all situations in which

> the peripheral joint of the chain meets with overwhelming external

> resistance. "

>

>

> Notice how Steidler not once, but twice mentions that the external

> resistance must be considerable or overwhelming to close the kinetic

> chain. So much that it does not simply move, but eventually moves.

Casler writes:

Thanks for your comments and I enjoy a good discussion about the OKC/CKC

concept and how it is best and most accurately interpreted.

The reason Steindler termed the " resistance " considerable, is that he didn't

want to contend with some one wearing a pair of gloves or shoes to be

considered " Closed " or closing since normally they do not restrict free

movement.

Steindler is very clear that the absolutely " closed kinetic chain " is

against an insurmountable load but any resistance that " restricts " free

movement closes the chain.

Tom Rankin wrote:

> These statements indicate CKCs consist of fairly formable loads.

Casler writes:

The reference to immovable might lead you to that conclusion, but the only

requirement is that the terminating load " restrict " .

He might have been better served to say that the terminating load be " acted

upon " by a complete kinetic chain. Complete meaning that it is a chain that

has two ends terminated to an external load in such a way that they impose

their force to the terminating load.

Tom Rankin wrote:

> Therefore, external resistances may exist in OKC as long as they do

> not restrict the free movement of the terminal joint. This is makes

> sense.

Casler writes:

The concept is designed to analyze and visualize how the body creates,

transmits and absorbs force. Since the body is not in a vacuum, you are

correct, it will always be dealing with " external " forces. The Closed Chain

concept is to track the chain from a " specific " load or base, to a

" terminating " load.

So you are correct, that external forces exist in Open Kinetic Chains, but

they are not terminating, so that the body becomes the " force chain " between

two loads or forces, like the feet on the ground to the dumbbell in the

hands. In this chain the forces run from the feet to the terminating load

in the hands.

I'm sure we can all think up " fringe " chains that might defy complete

classification, such as 5# work boots to close a chain, or waving your hands

in a swimming pool of chocolate pudding (now surely that restricts free

motion)

But the concept is not to explore the extreme fringes of infinite or

infinitesimal loads and forces, it is to provide a diagrammatic structure of

force analysis.

Tom Rankin wrote:

>Otherwise, the external resistance of the water makes

> swimming a CKC activity or gravity makes all our movements CKC.

Casler writes:

External resistance is not the only requirement to close a chain. You must

have 'termination' at both ends of the chain to close it.

While water can be an external force it does not offer any terminating

joint. That is why the body is acting on itself to react to a " nonspecific "

force. Swimming is the perfect example of an " absolutely " OPEN chain. I

think what your missing here is that the closed chain is " specific " and the

open chain is not. It is the force that is transited to the body, and

through the body to move itself.

Also be aware that a kinetic chain classification can change instantly to

the other, based on these terminations and what the force is transmitted to.

Tom Rankin wrote:

>If I

> am able wave my hand with a dumbbell, it is still consistant with

> Steidler's OKC definition.

Casler writes:

That is not true. A dumbbell " does " restrict " free " movement. Adding

" considerable " resistance restricts, free movement. What is considerable?

Any amount that restricts.

I would expect that you need to re-read my postings so that I don't end up

repeating too much, but in a nutshell the CKC is one that uses a combination

of body parts (forming a chain) that creates, transmits, or absorbs, load

from a base load/force (feet on the ground for example) to a terminal load

(dumbbell in hand).

An Open Kinetic chain obviously also operates against external forces but

has no " terminating " load so the chain is operating on itself which is free

to move

Tom Rankin wrote:

> The pushcart example may be compared to lifting a barbell overhead.

> The hands are restricted on the barbell much as they are on the

> cart. But if I switch to dumbbells, my hands are free to move.

> Watch anyone who had never trained with dumbbells and you'll see just

> how free the movement may be.

Casler writes:

Picking up a dumbbell " does " restrict free movement. The chain closes when

it transmits force through the chain from a base, to a terminal load.

Tom Rankin wrote:

>The problem with the Steider's

> pushcart example is that it is not just a CKC activity. The

> terminating joints are the hands and feet. Once the foot lifts off

> the ground to move forward, the pushing the cart goes from CKC to

> open OKC. Seems like the rest of us, Steidler, also had problems

> with this concept.

Casler writes:

Good thinking, except remember I said that the chain is a " snapshot " and can

change as soon as the requirements are met or changed.

Pushing a cart is actually a perfect example in that it displays the

alternating of Open to Closed, more clearly defining what each is.

As we bend over to pick up the cart handles we are forming an Open

Chain.(open from feet to hands) The " moment " we grasp the cart handles, and

" apply force " to the cart, we have terminated our force chain and channel

force into the cart.(feet to cart)

Now as we lift one foot and begin to push the cart we still have a " closed

chain " from the foot that is still in contact with the ground and an " open

chain " with the foot that is now " free to move " . Voila!!

So on one side we have a chain that is transmitting force into the external

terminating load of the cart and on the other we have an open chain.

Tom Rankin wrote:

> My 2 cents,

Casler writes:

And a good 2 cents it is. I think you are moving towards OKC/CKC

enlightenment. Let me assure you I have had a large amount of rather

contentious discussions with many of the caliber of our own Dr. Siff and

while the current interpretations are mired in the mud, my assertions hold

up as the only reasonable expansion on the subject that I have come across.

I am always interested in expanding it even more and making it more

accurate.

Keep your ideas coming.

Regards,

Casler

TRI-VECTOR 3-D Force Systems

Century City, CA