By looking for some inspiration and reference how to model muscular structures I found some quite impressive show-reels. The best example that I've seen so far was from Justi Romero. He was born in Barcelona(Spain) but now is living in London. He have been using 3D programs more than seven years, with experience in game and entertainment companies specialized in organic and hard surface modelling (high/low resolution meshes), creating realistic models, include human and creature characters, set and props. Check out his reel and portfolio.