Weak Links enhance Strength?

November 13, 2002

What Casler fairly casually write in his recent letter leads us to an

interesting new Puzzle & Paradox, namely that " a kinetic chain may be

stronger than its weakest link in a biological system. "

Casler:

<Regarding RFD, the transmission of force through the kinetic chain can only

be as efficient as the weakest link in that chain. So it would certainly

stand to reason that conditioning the " full " chain (chains) involved would

offer the best result.>

*** The saying that a " chain is only as strong as its weakest link "

certainly appears to be true in all rigid systems, but does it have to be

qualified or re-stated if it contains a sequence of links some of which are

rigid, non-rigid and fluidic? In such a case, the rigid elements are

stronger than the non-rigid elements and much 'stronger' than the fluidic

elements, so we are now compelled to examine how strength is defined in a

" linked " system.

Is this puzzle simply an intellectual diversion or does it have any relevance

to the body? Well, the body contains just this sort of system of different

links, with some links weaker than others. Does this necessarily mean that

the overall strength of the body will be limited by its weakest fluidic or

highly deformable components, which, after all are not as strong as the

bones and ligaments? Does the ability of these " weaker " elements cope with

this relative " weakness " depend on their doing exactly what they are meant to

do, namely to absorb shock, store elastic energy and transfer elastic energy?

In fact, their very " weakness " protects the more rigid parts of the body

from damage and enhances the efficiency of movement, thereby making it

" stronger " in coping with and in generating force.

Would this then not imply that even apparently " weak " links in a biological

chain can " strengthen " the overall performance of a linked kinetic chain, so

that we cannot directly apply that popular colloquial saying ( " a chain is

only as strong as its weakest link " ) without careful statement of its scope

and limitations in living systems?

Dr Mel C Siff

Denver, USA

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