So the issue is that there are SO many factors. Bones have nothing to do with it, it’s more about genetics. Things like myostatin proteins limit muscle growth. Animals that have mutated disruptions to the development of the protein have higher muscle mass - look up Belgium Blue cattle, you’ll see some BIG cows there.
Steroids help you recover more quickly, making it easier for you to work out more, and therefore put on more muscle. Not everyone is going to look like Arnold or Channing Tatum, your muscle distribution is going to vary entirely on your genetics, but you can absolutely look like a monster. You might just put on mass easier on your quads and your chest than your shoulders and calves, for example. Hyper-focusing on these elements will also warp your perspective. Sizes for gloves are arbitrary, so you might also be severely distorting your self-image. There’s a lot of different factors to consider.
I feel like it would be one of those high AC/low damage roll fights