>>2656406Muscle girl just has to be a girl with muscle.
A tomboy is a girl who partakes in activates and behaviors typically associated with boys.
They aren't the same, since you could have a very feminine muscle girl who just is naturally big and strong or just was very into fitness but otherwise tradcon wife material, and you could have a tomboy who's just sort of straight forward, crass and loves FPS games, action movies, heavy metal and drinking beer, but not particularly fit.
There's some decent overlap because sports, and especially weight lifting or sports that would emphasize strength and power, are thought of as mostly for men. So you have girls with an interest in a traditionally male activity, increasing the likelihood of such girls being tomboys or a higher amount of tomboyish qualities.
