Iggy Pop is a rock n roll pirate Gordy. A bit like Keith Richards in Pirates of the Caribbean. I don't have a problem with the muscle definition, just the bulk and size of his muscles. He's definitely been working out.
Here you go,
some images of the figures painted.
Cheers Nicolas
This almost looks like too different figures. Given the ripped/cut front, the "pose down" stance, there should be much more definition in the back musculature. The back suggests a certain softness, as the body builder commentators might say, like he's "holding too much water."