Cheerleadra's form is one I've often been tempted to make more muscular, but Cheerleadra's entire design is intended to be based on comic book superheroines who look more super model than bodybuilder in spite of their supernatural (or alien, or whatever) strength. This is reflected in Cheerleadra's overall build and her costume.
That said, I thought it would be nifty to draw Cheerleadra like this. So I did. And now it's a sketchbook. HUZZAH!