I like the fact that he's not all muscled up like a wrestler.
His skin was golden, his wide back muscled, lean and defined down to the slender hips and waist.
He was muscled like the panther-beast he turned into.
The front legs should be long and well muscled with accentuated withers, and the back legs should be powerful and well muscled.
The chest is deep, but the body is somewhat narrow while still well muscled.