Are the muscles from toning/for show, or are they built for maximum strength? Muscles aren't just one thing. Some of the most muscular people in the world are ultramarathon runners, and they're rail thin but ripped. Bodybuilders are also ripped, but much, much thicker. Then it becomes a matter of what type of competition they're having. Catfight, wrestling, etc? Are they in a confined space, or is there more room to move around? There's way more to it than just musculature.
Is the person with the extra mass fat, or just thick? A solidly built person with some extra bulk on them is way different than someone of the same size who is softer than a bag of marshmallows.