Exactly, Nark!One may be a generous, kind, loving and "Christian" (to go the whole ten yards) and be a bodybuilder, just as one may be all those things and a wealthy heiress or capitalist, or aristocrat, or communist... If bodybuilding helps bring you into the family of mankind, and doesn't lock you up and make all men your potential rivals and enemies, it has helped you realize your full humanity and is a good thing. Sin is, by its very nature, competitive. A sinful nature doesn't care about being rich, or beautiful, or muscular... the "joy" of sin comes in being MORE rich, or MORE beautiful, or MORE muscular than everybody else... and using that fact not to build up your own humanity, but rather to pull other people down, to make them feel "less than", worthless, unloved.
It is the spirit in which we perform our actions that they are judged.
Riches, good health, a beautiful body, social status, a prominent family, military or athletic victories are all GOOD things of which we can be proud. The problem of sin comes in when we set these things up as "false gods", expecting them to provide sustenance for our soul or solutions to life's problems. They can't. They're not up to the task.
The problem comes when Man, having once and for all pushed "God" out the front door, tries to smuggle something else in through the service entrance to take his place. Muscles won't be preached against as much as worldly "riches", in this respect, but then they are less likely to be taken as a "false god" and set off warning alarms in our head.
(Is this ME talking! "What have you done with BigLittleTim?")