The power of the centerline is known as 'Chushin-Ryoku'. When we maintain that strong center line in any direction we move, we have good posture and alignment. With a stable center and precise hanmi this structure is very powerful and sound.
The power that is generated by a unified body to focus on one point is called 'Shuchu-Ryoku'. This power is greater than muscular power.
The upper body only maintains an intregity (no strength) in coordination with the center, hips, and legs. The feet are foundational, drawing energy up from the ground.