Principle #2:

To have the best-looking abs, one needs to exercise them correctly and understand abdominal anatomy in addition to following principle #1.

This principle is pretty much self-explanatory and it leads us to the next topic, which is that of abdominal anatomy.

Abdominal Anatomy
There Are Four Main Muscle Groups That Make Up The Full Abdominal Wall:

• The Rectus Abdominis (composed of upper and lower abdominals)
  
• The Oblique Muscles
  
• The Intercostal Muscles
  
• The Serratus Anterior