I've always wondered why comic books use GROSSLY over developed muscles on action figures and I just assumed it was because they didnt take anatomy into consideration..... hmmm..
That mostly has to do with an artist's style and the flavor of the day. Look at Adam Hughes for more realistic figures compared to, say, Stephen Platt for blown out bodies. It's a stylistic preference.
Comic artists get in trouble when their figure education is other artists who have evolved a style, and not getting more classical training. If you learn to draw by copying Todd McFarlane, you're stuff will be wacky. Rob Liefeld is a great example of moderate talent with horrible understanding of the human figure.
There's an entire industry of artists who draw like Jim Lee, and they tend to stagnate in their artistic growth. Jim, however, has a solid foundation in figure drawing and can grow and change.
You might like some of the old-school artists. Look up John Buscema and Frank Frazetta for some outstanding figure art.