Raphael Albero paid a lot of attention to those muscles.
Raphael Albero showcased an impressively detailed 3D model of Wolverine inspired by Marvel vs. Capcom. The artist tried to make him closer to comic proportions, and this is what you probably see first in the sculpt.
Albero added extra details to the model's textures, so you can see every line in Wolverine's gloves and every hair on his giant arms – all thanks to ZBrush and Blender.
There is another version of the character in Albero's portfolio on ArtStation, where you can also find Earthworm Jim and Nightwing.