Neutral posture/pelvis is a dynamic place where you are ready to move at all times because you’re breathing and expanding rib cage allows your body to oscillate naturally. Neutral posture cannot be achieved from a fixed posture In neutral posture your torso is neither, slumped, arched, or hypermobile.
When you are in neutral posture, your pelvis is neither tipped forward nor backward. Your pelvis is aligned over the middle of your seat bones whether you are standing, sitting on a chair, or on a horse’s back. In this ideal posture, your upper body stabilizes itself automatically while rebalancing with each stride, whether you are walking or riding, because your core muscles can engage without bracing.
For more information, refer to Introduction to Connected Riding by Peggy Cummings.