I was (in another life many many years ago lol) a collegiate level sprinter. I was not a beefcake runner, but skinny as hell for a sprinter, still am tbh. Being able to lift weights has (almost) nothing to do with being fast. Although quite often the faster you get (above a certain threshold) the more your ability to lift heavy things increases.
All of this is to say as an amateur back-seat unqualified internet commentator, I would wager that speed bursting beyond your comfortable maximum on guitar has more to do with coordination and adaptation moreso than any actual muscular “training”. Being able to use only the necessary muscles to sprint at the expense of everything else so as to allow the constant contracting and relaxing of opposing forces sounds a lot like what needs to happen for higher speed guitar playing. Obviously not from a strength/force standpoint but from your muscles and brain needs to learn what it has to do to fire only those impulses that are needed for the coordinated motion of your arm hands and your hand fingers?
I dunno what is guitar anyway?!