/cgl/ - Cosplay & EGL

First time coplayer here. I have a "themed" ninja cosplay I'd like to create, and I have a question regarding the look.

My original idea was to buy a simple ninja costume to use as a base, then start tailoring around it (very basic tailoring skills) and adding the "theme" accessories, but most of them tend to be rather form fitting and would just make me look like a lanky nerd in a Halloween costume, as seen on the right.

How would I go about getting that "poofed" out leg effect like the image on the left, assuming it's possible / practical in reality? My original thought is that it's being caused by pant legs being "muffin topped" by the shin guards, but I'm not certain since I don't have a set to try.