I know it's still in-vogue to refer to the human body as a kinetic chain, but I'll suggest there's much, much more to factor than that of just a chain when trying to improve human performance for sports or tactical purposes. Certainly, there's an "inter-connection" of muscle that is acted upon to create movement, but I really think that this chain is more of a "linked" highway of interconnected systems and pathways at work.
Upon closer inspection, can you really train muscles without training movement? Can you really train movement without considering the muscles involved? Can we program to train muscles and movement without considering aspects of teach-ability, learning, behavior, motivation and the coach-athlete relationship? Can we train all of the aforementioned and neglect physiological aspects such as immune function, stress response, and brain function/development? How about health status, would this factor trump all the others?
This "linked system of interconnected pathways" called the human body is very complex and upon closer inspection there's more to this so-called "chain" than some connected steel. The same as there's more to developing athletes than lifting a barbell and attaining performance records.