In general, a "super strong" character with an average or only moderately buff physique will easily beat down even the most burly "normal". Characters may have big muscles in comic books to denote being super strong, but elsewhere this is often an exception.
Don't take these forms for granted, since they're often still strong enough to punch you across the room. Crossing the Bishōnen Line: A character with multiple forms may get more beastly and muscular, only to suddenly take on a form where they're less heavily built, sometimes losing quite a lot of muscle in the process.You can't have your Pretty Boy hero grow huge muscles without risking certain death at the hands of the Fan Girls. Generally, when it comes to important Big Guys, Muscles Are Meaningful. The Big Guy being physically dominated is usually a Giant Mook or similarly unimportant character. Alternatively, The Big Guy may not be very strong at all, but usually his strength is simply dwarfed in comparison. Usually lampshaded by Super Strength, and often more dubiously by a Charles Atlas Superpower. This is generally done to show just how badass they really are. A thin, wiry character may have no difficulty lifting or punching way above their weight class.
The Pintsized Powerhouse is able to physically outperform heavily-muscled guys ten times his size and is more than capable of sending them flying with a single punch, physics be damned. All things being equal, more muscle translates to more strength. note Per cross sectional unit area, healthy human muscle produces the same amount of force with little deviation, regardless of whether or not the muscle has been trained and factors such as age and sex. Muscle strength (force applied in Newtons) is proportional to the 'physiological cross-sectional area' (PCSA) or the total number of fascicles of the muscle. In Real Life, a person's physique, if not their physical size, is generally a dependable indicator of their physical strength.