For the actual muscle tissue under the skin (such as seen in anatomy pictures), please use exposed muscle. For unknown pink tissue that doesn’t have the lines seen in muscle tissue, use flesh.
Noticeably developed musculature that must have come from extensive training, body building or otherwise. The body has visually "bulked up" and has become obviously thicker.
Do not use pectorals size alone as a determinant for this tag. It is common in artwork to draw them disproportionately to the rest of the body, especially with manboobs etc.
Examples
Muscular
Plump muscular
If the physique is muscular with a belly like many wrestlers and bodybuilders, consider adding the plump, belly and/or strongman waist tag as well.
Toned physique
If the character has an athletic build that’s not overly bulky, use toned instead. Do not use muscular with the toned tag when describing one character.
