Edge loop/Edge flow

I found a website which shows the importance of edge looping and how they're they're placed for when movement occurs and deformation happens in animation. They're used to separate areas and define shapes and direct edge flow.

Below, I found this interesting as it shows the main areas which are effected in movement;

http://www.cgmascot.com/design/modeling-for-animation-body/

'What are the Main Masses moving in a human/humanoid?

 

• Back of a character bends below the chest.  You need loops going around the torso.  Chest bends too, even the rib cage below deforms, however the musle masses on chest and shoulder & back-area have more effect on the shape change, shoulder having clearest effect. You should have flow from chest directed to flow over the shoulder and to the back. Please note my optimization here has lead to a pole, a 6 edges intersection, in the middle of the back. It is not troubling me, but if you build similiar mesh you may want to add few polygons in that region to get rid of the pole.
• The arm-mass connects to the shoulder and the problem area is over the arm-socket.
• Head and neck moving about affects the area around the neck and some ways to the back.
• Legs move the buttocks as well.   The mass movement limits to top of the hip bone, pretty much.
• With arms and legs the problematic bits are knee and elbow both. Masses of back- and forelimb come together and separate there.  The loops help to give more mass on the outside part of the bending limb, giving material for both parts that bend away and a centerline that stays more or less in place. You may get by with a tube-like structure here for cartoon-characters where things aren’t that exact OR by having many loops that you carefully weight to bones to deform just right.'