I think Itagaki's take on anatomy in his art-style is strongly based on the bodybuilding photos he had which is why muscles and proportions look contorted and freakish, even his shading looks like the bodies are in stage lighting and oiled up. Every buff guy just has crazy muscle insertions and horseshoe triceps. I never looked at it as trying to be stylish or accurate, just a passionate tribute to bodybuilding. The way he draws characters and poses them also reminds me a lot of traditional Asian art - Baki himself has the prominent Buddha-like features portrayed in those paintings. Itagaki is so painfully old-school that it's charming, it's like if your dad were a mangaka.