The easiest fix would be to put all posts that contain "muscle" without "muscle memory" (since numerous questions use that phrase legitimately) through the Low Quality Posts review queue.
I realize that's not optimal, since LQP isn't really designed for flagging/identifying spam. An alternative would be to insert it as a task for First Posts at the top for quickest handling, since the vast majority of spam, in my experience, is its user's first and only post.
Sometimes I really wish Super User had a Triage queue for stuff like this.