But seriously.

The ravages of Syphilis are no laughing matter.  And there is no real cure.*

I don't have the dreaded Syph, or even the Drip, but I suspect my spine issue are congenital.  It goes a lot to explaining my lack of athletic skill, or progression in same even when I work at it.  The passaged for the nerver branching off the main trunk are more constricted than average.  And that constriction has always prevent proper enervation.  The muscle may be toned, hard, and fit, but if the signal isn't there, it can't do its job.  

It's a flaw in the electronics, not the hydraulics, in other words.  Not enough to keep me out of the military, but enough to keep my Physical Fitness scores in the basement of passing.  Similar issues probably also afflicted a bunch of other PT slugs you knew.  They weren't all just Lazy Sacks that lacked the fortitude.  

Which is no big deal.  Not everyone is destined to be a Marine, a SEAL, or a Ranger.  Some are blessed with good athletic acumen from day one, others, not so much.  But you need folks in the motorpool and watch standers aboard ship, and ATC monitoring the radars.  

* Information garnered from a 1939 Funk and Wagnalls encyclopedia.