The principal of ribcage placement helps us understand how the vertebrae and ribs are connected and how our abdominals can help stabilize both. We use the term "popping" meaning that the ribs shouldn't "pop" up as your arms go over head. The deep abdominals activate to help pull the ribs down and close the ribcage.

Likewise, when the arms are down, we want to keep the top of the body, resting flat on the floor. In other words, the ribcage that is right under your shoulder blades in the back says flat and doesn't roll forward.

This principal is an interesting one and it really helps you see the extent of our core stability.