Neutral Spine...

When lying on your back with neutral spine, you should be able to balance a teacup on your lower belly. If you tilt your pelvis forward too much (by arching your back off the mat), your teacup will spill forward. This is called anterior pelvic tilt. If you tilt your pelvis backward (by flattening your back on the floor), you’ll spill your teacup backward. This is called posterior pelvic tilt. Neutral spine is when the teacup doesn’t spill.

Neutral pelvis is actually defined as the pubic bone and hip bones being on the same plane. You can feel these bony landmarks with your fingers if you’re lying down, and this triangle of bones, when neutral, should create a flat table for your teacup. When standing up, you want to translate this idea of neutral pelvis to the upright position. When you’re standing, the plane (or tabletop) created by the neutral pelvis should be perpendicular to the floor; you don’t want your pubic bone pointing forward or back, but dropping straight down to the ground. Many people have the tendency to tilt their pelvis in one direction or the other, and either of these postural habits can cause strain to the body over time. Neutral spine (neutral pelvis) is just simply good posture, and when you have good posture, your muscles don’t have to work so hard to keep you upright and moving.