When the body is in perfect alignment, breathing is improved, blood flows well, the spine’s disks are well cushioned, and no one muscle group works harder than another.
But perfect posture doesn’t mean standing like a sentry. The spine’s curves, at the neck and the small of the back, actually make it stronger than if it were perfectly straight. Problems arise when you stand in a way that exaggerates these curves.
To achieve the ideal posture, tuck in your tailbone slightly, lift your chest, drop your shoulders, and tighten your abdominal muscles. Your feet should be flat on the floor, and your knees soft, with a little spring in them. When you’re sitting, your feet should be flat on the floor and your knees slightly apart. Periodically throughout the day, take time to check your alignment. After about six weeks, standing up for yourself should feel totally natural.